JP2007074747A - Electroacoustic transducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroacoustic transducer capable of emitting a sound wave without abnormality against a large amplitude input. <P>SOLUTION: The electroacoustic transducer has a flange 2D wherein an end 2E along at least the length direction of an edge 2 rises so as to face a vibrating direction of a diaphragm 1, and a tip of the flange 2D is fixed to a long frame 3A or a short frame 3B of a frame 3. Further, a track shaped roll 3C is formed so that the width and the projected height in a vicinity of articulation M1 between its long side part LA and a circular-arc part SA are gradually increased toward a top T of the circular-arc part SA from the vicinity of articulation M1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electroacoustic transducer, and more particularly to a narrow (elongated) shaped speaker.

For example, speaker units mounted on a television set are usually arranged on both sides of the screen so as to obtain an optimal sound effect. On the other hand, TV sets are required to be as small as possible with the increase in screen size and width, and the width of the speaker unit can be widened while pursuing high sound quality. There is a need to make it as small as possible.
In order to meet the demand, various types of speaker units having a narrow structure such as a rectangular shape and an elliptical shape have been provided. As an example of such a narrow-width speaker, there is one described in the prior art column of Patent Document 1.

JP 2002-325294 A (see paragraph numbers 0002 to 0009)

An example of such a conventional electroacoustic transducer 20 having a narrow structure will be described with reference to FIGS.
FIG. 12A and FIG. 12B are a front view and a cross-sectional view taken along line AA of the conventional electroacoustic transducer 20 having a narrow structure, respectively.
In these drawings, the diaphragm 21 has a long shape and a short diameter as viewed from the vibration direction, and is continuously formed with uneven portions in the direction of sound emission. An edge 22 is joined to the outer peripheral portion of the diaphragm 21, and the edge 22 is further held by a frame 23. The frame 23 in FIG. 12A is simply represented.

A track type voice coil bobbin 24 is fixed to the lower end of the outer peripheral portion of the diaphragm 21. A voice coil 25 is wound around the outer peripheral surface of the voice coil bobbin 24. The voice coil bobbin 24 is suspended in a magnetic gap G of a magnetic circuit, which will be described later, and generates a driving force by an audio signal current and magnetic flux.
The frame 23 is formed in a frame shape, and a part of the side surface thereof is shaped along the side portion of the edge 22.

The magnetic circuit is attached to the inner lower part of the frame 23.
This magnetic circuit includes an iron yoke 26, a magnet 27, and a pole piece 28, and is fixed at a predetermined position on the frame 23. The pole piece 28 is provided at a position corresponding to the main vibration portion of the diaphragm 21.

Next, a specific configuration of the diaphragm 21 and the edge 22 joined to the outer peripheral portion of the diaphragm 21 and held by the frame 23 will be described.
As described above, the vibration plate 21 has a shape in which the planar shape viewed from the vibration direction has a major axis and a minor axis, and is continuously curved in an uneven shape in the direction of sound emission. That is, it has a shape in which convex portions 29a and concave portions 29b are alternately and continuously formed. Moreover, the depth dimension D of each concave-shaped part is formed in substantially the same grade.

  The diaphragm 21 is formed of a polyimide (PI) film that can withstand the heat generation of the voice coil 25 and has excellent mechanical characteristics as the diaphragm 21. Further, the groove portion 29 c is provided at a substantially central portion of the diaphragm 21.

By the way, as the width of the edge 22 in the minor axis direction is wider, a range in which linear response can be made to the applied driving force is widened, and the maximum amplitude can be set larger.
However, as described above, it is desired that the width of the speaker unit is narrower. For this purpose, the width of the edge 22 needs to be reduced. This makes it more difficult to maintain linearity in the response. For this linearity, the width of the edge 22 is greatly involved.

The degree of influence on the linearity is clarified by observing the stress generated in the vicinity of the edge frame joint when the amplitude of the sound to be reproduced is large. It can also be known from the distortion characteristics of the speaker.
FIG. 13 is a diagram showing an example of a stress distribution generated in the vicinity of the joint portion of the edge 22 with the frame by simulation.

In the conventional edge, it is known that the longitudinal direction also vibrates easily and a stress deviation occurs depending on the part, but FIG. 13 shows that a high stress concentration occurs in the longitudinal direction so as to support this. Yes. This stress concentration adversely affects electrical characteristics and sound quality.
Further, FIG. 14 shows an example of acoustic characteristics of a speaker having a conventional edge. This figure shows that both the second harmonic distortion and the third harmonic distortion have large characteristics. Needless to say, this large distortion adversely affects the sound quality.

  Therefore, the problem to be solved by the present invention is to provide an electroacoustic transducer capable of emitting sound waves without abnormality for a large input.

In order to solve the above problems, the present invention has the following configuration as means.
That is, according to the first aspect of the present invention, the diaphragm 1 has a substantially oval-shaped diaphragm 1 and an elongated outer shape larger than the diaphragm 1, and the diaphragm 1 is disposed at a substantially center to support the diaphragm 1. The frame 2 has a substantially frame shape having an edge 2, a pair of long frames 3A and a pair of short frames 3B, and an end 2E of the edge 2 is fixed to each frame, and the diaphragm 1 is An electroacoustic transducer comprising a frame 3 that is supported so as to be free to vibrate via the edge 2;
At least the end portion 2E along the longitudinal direction of the edge 2 has a flange portion 2D that rises toward the vibration direction of the diaphragm 1, and the front end side of the flange portion 2D is the longitudinal frame 3A or the short frame. It is an electroacoustic transducer characterized by being fixed to 3B.
Further, the present invention has a substantially elliptical diaphragm 1 and an outer shape that is larger than the diaphragm 1 and supports the diaphragm 1 by disposing the diaphragm 1 at a substantially center thereof. In addition, the diaphragm 2 has an edge 2 formed with a roll portion 2C projecting in an oscillating direction having a circular cross section around the diaphragm 1, a pair of long frames 3A, and a pair of short frames 3B. The frame 3 is substantially frame-shaped, and has a frame 3 on which the edge 2E of the edge is fixed to each of the frames 3A and 3B, and supports the diaphragm 1 so as to be free to vibrate via the edge 2. The roll portion 2C is formed in a track shape composed of a pair of longitudinal portions facing each other along the longitudinal direction of the edge 2 and a pair of arc-shaped portions connecting the pair of longitudinal portions at both ends thereof. In an electroacoustic transducer,
The roll portion has a width and a protruding height in a cross-sectional shape in the vicinity of the connecting portion M1 where the longitudinal portion LA and the arc-shaped portion SA are connected, and the top portion T of the arc-shaped portion SA from the connecting portion vicinity M1. It is an electroacoustic transducer characterized by having a portion formed so as to gradually increase as it goes to.
Further, according to a third aspect of the present invention, at least the end portion 2E along the longitudinal direction of the edge 2 has a flange portion 2D that rises toward the vibration direction of the diaphragm 1, and the front end side of the flange portion 2D is the longitudinal direction. The electroacoustic transducer according to claim 2, wherein the electroacoustic transducer is fixed to the frame 3A or the short frame 3B.

  As described above in detail, according to the present invention, the linearity of the diaphragm is improved, sound waves can be radiated without abnormality for a large input, and the width direction in the outer shape can be further reduced. obtain.

The preferred embodiments of the present invention will be described with reference to FIGS.
FIG. 1 is a diagram showing an embodiment of the electroacoustic transducer of the present invention,
FIG. 2 is a cross-sectional view illustrating an embodiment of the electroacoustic transducer of the present invention. FIG. 3 is a perspective view illustrating a diaphragm in the embodiment of the electroacoustic transducer of the present invention.
FIG. 4 is a perspective view illustrating a voice coil in an embodiment of the electroacoustic transducer of the present invention.
FIG. 5 is a plan view for explaining a frame in an embodiment of the electroacoustic transducer of the present invention.
FIG. 6 is a perspective view for explaining an edge in an embodiment of the electroacoustic transducer of the present invention,
FIG. 7 is a cross-sectional view illustrating an edge in an embodiment of the electroacoustic transducer of the present invention,
FIG. 8 is a perspective cross-sectional view for explaining the main part of the edge in the embodiment of the electroacoustic transducer of the present invention,
FIG. 9 is a diagram illustrating stress concentration in one embodiment of the electroacoustic transducer of the present invention.
FIG. 10 is a diagram for explaining stress concentration in an embodiment of the electroacoustic transducer of the present invention,
FIG. 11 is a diagram illustrating characteristics of a preferred embodiment of the electroacoustic transducer of the present invention.

First, a specific configuration will be described mainly with reference to FIGS.
FIG. 1A is a plan view thereof, and FIG. 1B is a half sectional view taken along line AA of FIG. FIG. 2 is a cross-sectional view taken along line BB in FIG.
The electroacoustic transducer 10 includes a diaphragm 1, an edge 2, and a frame 3, and the outline will be described below.

The diaphragm 1 is a long round member having a major axis and a minor axis, and composed of opposed long sides and a substantially arcuate part connecting the ends thereof (see FIG. 3).
The edge 2 is a member that is joined to the outer periphery of the vibration plate 1 and holds the vibration plate 1 with respect to the frame 3 so as to freely vibrate. It is a member (see FIG. 6).
The frame 3 is a substantially frame-shaped support body that supports each member, and the long and short frame portions and the outer periphery of the edge 2 are joined to support the edge 2 (see FIG. 5).
A track-type voice coil bobbin 4 as shown in FIG. 4 is fixed to the lower end of the outer peripheral portion of the diaphragm 1. A voice coil 5 is wound around the outer peripheral surface of the voice coil bobbin 4.
The voice coil bobbin 4 is suspended in a magnetic gap G of a magnetic circuit, which will be described later, and generates a driving force by an audio signal current and a magnetic flux.

A magnetic circuit is attached to the inside of the frame 3 (see FIGS. 1B and 2).
This magnetic circuit includes a U-shaped yoke 6 made of iron, a magnet 7 fixed to the inside of the yoke 6, and a main vibration portion (generally a concave convex portion provided on the vibration plate 1 at the tip of the magnet 7. Range) and a pole piece 8 provided to face 1A.

Next, (1) the diaphragm, (2) the edge, and (3) the frame will be described in detail.
(1) Diaphragm 1 As described above, the diaphragm 1 is an elongated round member having a major axis and a minor axis, and having a long side facing each other and a substantially arcuate part connecting its ends. The main vibration portion 1A having a concavo-convex shape and a flange portion 1B formed around the main vibration portion 1A are provided. The end angle in the longitudinal direction is R-shaped.
In the main vibration portion 1A, concave and convex portions that are uneven in the vibration direction V are formed continuously in the major axis direction. That is, convex portions 11a to 11f and concave portions 12a to 12d that are alternately continuous are formed.
Further, the depths D1 of the recesses 12a to 12d are formed to be substantially the same except for the central part.

The diaphragm 1 is formed of a polyimide (PI) film because it withstands heat generation during the operation of the voice coil 5 and has excellent mechanical characteristics as a diaphragm.
A groove portion 9 is provided in a substantially lateral direction of the diaphragm 1 in the lateral direction. The depth D2 of the groove 9 is set to be substantially the same as the dimension C in the depth direction of the shoulder 14 provided at the longitudinal end of the main vibration portion 1A.

(2) About edge 2 (see FIGS. 2, 6 and 7)
As described above, the edge 2 is a member formed in a substantially frame shape having the opening portion 2 </ b> A in which a portion substantially corresponding to the outer shape of the diaphragm 1 is opened.
Specifically, as shown in FIG. 2 and FIG. 6, the flat portion 2B provided with the above-described opening 2A, and the outer side of the flat portion 2B are projected and formed in a track shape so that the cross section is substantially arc-shaped. 2C, and a flange portion 2D raised up so as to be folded back in a direction opposite to the protruding direction of the roll portion 2C on the side in the longitudinal direction outside the roll portion 2C. The roll portion 2C is formed so that its cross-sectional shape gradually changes on the short side of the edge 2, that is, on the arc-shaped portion of the roll portion 2C.
Here, the track shape means a pair of longitudinal portions (longitudinal regions LA) facing each other along the longitudinal direction of the edge 2 and a pair of substantially arc-shaped portions (short) that connect the pair of longitudinal portions at both ends thereof. Means a shape consisting of the hand area SA).

The gradual change of the cross-sectional shape will be specifically described with reference to FIG.
FIG. 8 is an enlarged view of one corner portion P of FIG. 6 and shows a state in which the diaphragm 1 is fixed to the edge 2.
In the longitudinal region LA of the edge 2, the roll portion 2 </ b> C is formed so that the cross-sectional shape composed of the outer curvature R <b> 1, the protrusion height h <b> 1, and the roll width W <b> 1 is constant.
Here, the roll width W1 is a distance W1 between the inner boundary line 2C1 and the outer boundary line 2C2 where the roll part 2C contacts the surface of the edge 2 (flat part 2B), and is hereinafter referred to as a distance W1.

This cross-sectional shape is such that, in the short area SA, the protrusion height h1 and the interval W1 gradually increase toward the top T of the arc, and at the position of the central axis CL1 extending in the longitudinal direction of the edge 2, respectively. It is formed to have the maximum (outer curvature R2, protrusion height h2, interval W2). The roll portion 2C is formed so as to be axially symmetric with respect to the axis CL1. In this embodiment, the enlargement ratios R2 / R1, h2 / h1, and W2 / W1 are set to 1.2.
The change portion M1 that is the change start point of the cross-sectional shape may not be the connection portion M between the longitudinal region LA and the arc-shaped region SA, and may be set in the vicinity of the connection portion M.
Further, the apex side end (change end point) M2 of the gradually expanding range may be set before the apex T instead of the apex T. In any form, the change portion M1 (change start point) and the apex side end portion M2 (change end point) are smoothly connected to the non-change range so that a bending line does not occur.

  In addition, assuming that the center line CL2 of the roll part 2C is similar to the line 2AL of the arc-shaped part in the opening 2A of the edge 2, the roll part 2C has a gradual change in the cross-sectional shape of the roll part 2C. The distance Win between the inner boundary line 2C1 and the center line CL2 and the distance Wout between the outer boundary line 2C2 and the center line CL2 are formed to be equal.

As a material for the edge 2, butyl rubber can be used. The material is not limited to this material as long as it has excellent heat resistance and vibration characteristics.
As shown in FIG. 2, the diaphragm 1 is inserted from the inside of the opening 2A (the lower side of the figure), and the upper surface of the flange portion 1B of the diaphragm 1 and the lower surface of the flat portion 2B of the edge 2 are adhesives. Both are integrated by being fixed by.

(3) Frame 3 As described above, the frame 3 is a support body formed in a substantially frame shape that supports each member, and includes a pair of long frames 3A in the longitudinal direction and a pair of short frames in the short direction. 3B is connected (see FIG. 5).
The short frame 3B is provided with a fastening hole 3B1 for fixing the frame to another member.
Further, on the inner side of the short frame 3B, a collar portion 3B2 connected to the long frame 3A and having an arc-shaped end portion is provided (see FIGS. 1B and 5).
A step 3A1 including a wall 3A1a and a bottom 3A1b that comes into contact with the wall 3A1a is provided on the outer surface of the longitudinal frame 3A (see FIG. 2).

In FIG. 2, the edge 2 is placed on the frame 3 from above in the figure. In the longitudinal direction, the inner surface of the flange 2D of the edge 2 and the wall 3A1a of the longitudinal frame 3A of the frame 3 are bonded to each other. Secure with.
On the other hand, in the short direction, the lower surface of the flat portion 2E at the end portion of the edge 2 in the longitudinal direction and the upper surface of the flange portion 3B2 of the frame 3 are fixed with an adhesive.
By these fixing, the frame 3 and the edge 2 are integrated, and the diaphragm 1 is supported so as to be free to vibrate via the edge 2 with respect to the frame 3.

Next, the operation of the electroacoustic transducer 10 configured as described above will be described.
In this configuration, when a drive current flows through the voice coil 5 wound around the voice coil bobbin 4 in a magnetic field generated by the magnet 7, an electromagnetic force corresponding to the drive current acts on the voice coil bobbin 4 and is integrated with the coil bobbin 4. The formed diaphragm 1 vibrates mainly with the main vibration part 1A.

At this time, as described above, the flange portion 2D is formed on the side surface of the edge 2, and the front end side of the flange portion 2D is fixed to the frame 3, whereby the roll portion 2C that mainly supports the diaphragm 1 elastically. Since the end of the flange portion 2D where the edge 2 is supported by the frame 3 is positioned in the vibration direction with respect to the outer boundary line 2C2, the boundary line does not increase the width of the edge 2 The distance between 2C2 and the end of the flange portion 2D can be increased to improve the linearity.
Further, by gradually changing the cross-sectional shape of the roll portion 2C in the short region SA so as to gradually expand from the long region LA toward the top portion T, the linearity of the amplitude of the diaphragm 1 is dramatically improved. The stress level at the outer periphery of the edge 2 is drastically reduced and stress concentration can be prevented.

Further, in the side portion of the edge 2 in the longitudinal direction, the margin of bonding with the frame 3 is not necessary on the flat portion 2E outside the roll portion 2C, so that the width of this portion can be made extremely small.
Accordingly, the outer dimension of the electroacoustic transducer can be formed smaller in the width direction.

The stress generated at the edge 2 when the electroacoustic transducer having the above-described configuration is vibrated will be described with reference to FIGS.
FIG. 9 is a perspective view illustrating the stress concentration when the flange portion 2D is provided on the edge 2 and the tip portion is fixed to the frame, as viewed from the corner of the edge 2 from the inside.
10 illustrates the stress concentration when the cross-sectional shape of the roll portion 2 is gradually changed in the enlargement direction in the short area SA in addition to the configuration shown in FIG. FIG.

Comparing these figures with FIG. 13 in the case of using the conventional edge, when the flange portion 2D is provided (FIG. 9), although stress concentration occurs, the range is extremely local. I understand that.
Therefore, the range in which the amplitude response is linear is expanding, indicating that the adverse effect on the electrical characteristics and sound quality is extremely reduced.

On the other hand, when the cross-sectional shape of the roll part 2C is gradually changed in the enlargement direction in the short area SA in addition to the formation of the flange part 2D (FIG. 10), no stress concentration occurs.
Therefore, the range in which the amplitude response is linear is dramatically expanded, which indicates that the adverse effect of stress concentration on the electrical characteristics and sound quality can be completely eliminated.

Further, FIG. 11 shows a sound pressure frequency characteristic of the electroacoustic transducer 10 in this embodiment and a frequency characteristic diagram of harmonic distortion.
Comparing this figure with FIG. 14 which is a conventional frequency characteristic diagram, in this embodiment, the second harmonic distortion and the third harmonic distortion are greatly reduced without any loss of the sound pressure characteristic. It turns out that it is decreasing. This indicates that the adverse effects of these distortions on the sound quality can be greatly reduced.

  The embodiments of the present invention are not limited to the above-described configuration, and may be modified as follows, for example, without departing from the scope of the present invention.

The flange portion 2D does not limit the length in the longitudinal direction, the rising angle, and the rising length, but the most desirable form is the following form.
That is, the length in the longitudinal direction is provided in a range substantially corresponding to the main vibration portion of the diaphragm 1, and the angle is set up in the vibration direction. It is desirable that the rising length is as long as possible.

  Further, a flange portion raised like the side portion may be provided on the end portion side of the edge 2 in the longitudinal direction, and the leading end portion of the flange portion may be fixed to the frame 3.

  Regarding the gradual change of the cross-sectional shape of the roll portion 2C, (W1 / 2) = Win may be set so that the inner boundary line 2C1 and the line 2AL of the arc-shaped portion of the diaphragm 1 have a similar shape, (W1 / 2) = Wout may be used so that the outer boundary line 2C2 and the line 2AL are similar to each other, but the configuration of the above-described embodiment in which Win = Wout is gradually expanded is the most preferable form. is there.

The enlargement ratio of the roll part 2C is not limited to 1.2. An optimum enlargement ratio can be set depending on the shape and material of the diaphragm 1. Further, this ratio may be set to be different for each of the outer curvature, the protrusion height, and the roll width.
At that time, the enlargement ratio of the outer curvature may not be changed as R2 / R1 = 1.
The uneven shape provided in the main vibration portion 1A of the diaphragm 1 is not limited to the shape described above, and the shape of the main vibration portion 1A can be arbitrarily set.

It is a figure which shows the Example of the electroacoustic transducer of this invention. It is sectional drawing which shows the Example of the electroacoustic transducer of this invention. It is a perspective view explaining the diaphragm in the Example of the electroacoustic transducer of this invention. It is a perspective view explaining the voice coil in the Example of the electroacoustic transducer of this invention. It is a top view explaining the flame | frame in the Example of the electroacoustic transducer of this invention. It is a perspective view explaining the edge in the Example of the electroacoustic transducer of this invention. It is sectional drawing explaining the edge in the Example of the electroacoustic transducer of this invention. It is a perspective sectional view explaining the important section of the edge in the example of the electroacoustic transducer of the present invention. It is a figure explaining the stress concentration in one Example of the electroacoustic transducer of this invention. It is a figure explaining the stress concentration in the Example of the electroacoustic transducer of this invention. It is a figure explaining the characteristic of one preferable Example of the electroacoustic transducer of this invention. It is a figure explaining the conventional electroacoustic transducer. It is a figure explaining the stress concentration in the conventional electroacoustic transducer. It is a figure explaining the characteristic of the conventional electroacoustic transducer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Diaphragm 1A Main vibration part 1B Flange part 2 Edge 2A Opening part 2AL Line 2B Flat part 2C Roll part 2C1 (Inside) boundary line 2C2 (Outside) boundary line 2D Flange part 2E (Outside roll part) Flat part 3 Frame 3A Longitudinal frame 3A1 Step 3A1a Wall 3A1b Bottom 3B Short frame 3B1 Fastening hole 3B2 Gutter 4 Voice coil bobbin 5 Voice coil 6 Yoke 7 Magnet 8 Pole piece 9 Groove 10 Electroacoustic transducers 11a-11f Protrusions 12a-12d Recess 14 Shoulder C, D1, D2 Depth CL1, CL2 Center axis G Magnetic gap V Vibration direction M Connection part M1 Change part (near connection part) (change start point)
M2 vertex side end (end of change)
T top LA long area SA short area h1, h2 protrusion height R1, R2 curvature W1, W2 interval Win, Wout distance

Claims (6)

An elongated diaphragm,
An edge having an elongated shape larger than the diaphragm, and an edge for supporting the diaphragm;
A substantially frame shape having a pair of long frames and a pair of short frames, wherein the edges are fixed to the frames, and the diaphragm is supported to be free to vibrate via the edges. An electroacoustic transducer comprising a frame to perform,
A flange portion extending along the vibration direction of the diaphragm is formed on a side surface along the longitudinal direction and the short direction of the edge, and the leading end side of the flange portion is fixed to the long frame or the short frame of the frame, respectively. An electroacoustic transducer characterized by that. An elongated diaphragm,
An edge having an elongated outer shape larger than the diaphragm, and a roll portion that supports the diaphragm and that protrudes in a vibration direction having a substantially arc-shaped cross section around the diaphragm;
A substantially frame shape having a pair of long frames and a pair of short frames, wherein the edges are fixed to the frames, and the diaphragm is supported to be free to vibrate via the edges. And a frame to
The electroacoustic formed in a track shape in which the roll portion is composed of a pair of longitudinal portions facing each other along the longitudinal direction of the edge and a pair of arc-shaped portions connecting the pair of longitudinal portions at both ends thereof A converter,
The roll part gradually increases in width and protrusion height in the cross-sectional shape in the vicinity of the connecting part where the longitudinal part and the arcuate part are connected, from the vicinity of the connecting part toward the top of the arcuate part, And the electroacoustic transducer is formed so that the gradual expansion ends before the top of the arcuate portion. An elongated diaphragm,
An edge having an elongated outer shape larger than the diaphragm, and a roll portion that supports the diaphragm and that protrudes in a vibration direction having a substantially arc-shaped cross section around the diaphragm;
A substantially frame shape having a pair of long frames and a pair of short frames, wherein the edges are fixed to the frames, and the diaphragm is supported to be free to vibrate via the edges. And a frame to
The electroacoustic formed in a track shape in which the roll portion is composed of a pair of longitudinal portions facing each other along the longitudinal direction of the edge and a pair of arc-shaped portions connecting the pair of longitudinal portions at both ends thereof In the converter,
The roll portion is formed such that the width of the cross-sectional shape in the vicinity of the connecting portion where the longitudinal portion and the arc-shaped portion are connected gradually increases from the vicinity of the connecting portion toward the top of the arc-shaped portion. An electroacoustic transducer, characterized by comprising: An elongated diaphragm,
An edge having an elongated outer shape larger than the diaphragm, and a roll portion that supports the diaphragm and that protrudes in a vibration direction having a substantially arc-shaped cross section around the diaphragm;
A substantially frame shape having a pair of long frames and a pair of short frames, wherein the edges are fixed to the frames, and the diaphragm is supported to be free to vibrate via the edges. And a frame to
The electroacoustic formed in a track shape in which the roll portion is composed of a pair of longitudinal portions facing each other along the longitudinal direction of the edge and a pair of arc-shaped portions connecting the pair of longitudinal portions at both ends thereof In the converter,
The roll portion is formed such that the projecting height of the cross-sectional shape in the vicinity of the connecting portion where the longitudinal portion and the arc-shaped portion are connected gradually increases from the vicinity of the connecting portion toward the top of the arc-shaped portion. An electroacoustic transducer characterized by being made.   3. A flange portion extending along a vibration direction of the diaphragm is formed on a side surface along the longitudinal direction of the edge, and a front end side of the flange portion is fixed to a longitudinal frame of the frame. The electroacoustic transducer according to claim 4.   A flange portion extending along the vibration direction of the diaphragm is formed on a side surface along the longitudinal direction and the short direction of the edge, and the leading end side of the flange portion is fixed to the long frame or the short frame of the frame, respectively. The electroacoustic transducer according to any one of claims 2 to 5, wherein the electroacoustic transducer is provided.

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