JP6711487B2 - Electro-acoustic transducer - Google Patents

Description

The present invention relates to an electroacoustic transducer, and more particularly, an earphone and a headphone worn on a user's ear or head, a speaker device such as a large speaker, and an improvement of an electroacoustic transducer that can be used as a microphone. Regarding

Conventionally, as a speaker device to be worn on a user's ear, as shown in FIG. 6, for example, one end surface of a drive magnet 5 is fixed in a cup-shaped yoke 3 arranged in a case body 1 to drive the drive magnet 5. A thin vibrating film 7 facing the other end face with a space is fixed to the tip of the yoke 3 with an adhesive or the like, and a cylindrical voice coil 9 fixed to the vibrating film 7 is slightly attached to the outer periphery of the drive magnet 5. It is well known that the inner magnet type structure is inserted at a certain interval.

The case body 1 includes a funnel-shaped base portion 1a and a front cover 1b that covers the tip (the right side in FIG. 6), and a flexible ear tip (ear pad, ear piece) is attached to the outer periphery of the sound passage cylinder 11 protruding from the front cover 1b. ) 13 is fitted.

Reference numeral 15 in FIG. 6 is a cable led to the outside, and this knot 15a is inside the base portion 1a.

In this speaker device, a drive unit 17 for vibrating the vibrating membrane 7 is formed by the driving magnet 5 and the voice coil 9, and an audio signal is externally applied to the voice coil 9 by the cable 15 to vibrate the vibrating membrane 7 to produce a sound. The generated sound is transmitted to the outside from the sound passage cylinder 11 on the front surface of the vibrating membrane 7.

The speaker device as an actual product is configured as, for example, an ear canal insertion type earphone device, and vibrates in the conchal cavity 25 surrounded by the tragus 19, the tragus 21, and the concha 23 of the user. Insert the case body 1 so that the membrane 7 is brought close to the concha 23 and elastically contact the ear tip 13 with the inner wall of the external auditory meatus 27 extending from the concha cavity 25 to the eardrum (not shown). used.

As the actual product, as shown in FIG. 6 described above, a coaxial type in which the central axis of the sound-transmitting cylinder 11 is aligned with the central axis of the vibrating membrane 7, and although not shown, the central axis of the vibrating membrane 7 has a sound-transmitting characteristic. There is a non-coaxial type in which the central axis of the cylindrical body 11 is set obliquely. FIG. 6 shows a state in which the earphone device is attached to the left ear.

By the way, as a publicly known example of an earphone, there is JP-A-2010-283643 (Patent Document 1), and as a publicly known example of a speaker device, there is JP-A-2008-118331 (Patent Document 2).

JP, 2010-283643, A JP, 2008-118331, A

Then, when the configuration of the speaker device shown in FIG. 6 is slightly modified and shown in detail for easy understanding, it becomes as shown in FIG. 7, for example.

That is, referring to FIG. 7, in the speaker device described above, the cup-shaped yoke 3 has a through hole 3b at the center of the bottom portion 3a thereof, and the open end side of the tubular portion 3c of the yoke 3 is bent outward to be a flat support. It has a piece 3d, and the tip outer peripheral portion of the support piece 3d is slightly raised along the axial direction to form an annular fixing portion 3e.

Further, in the yoke 3, the drive magnet 5 and the ring-plate-shaped pole piece 29 are overlapped and integrally fixed to the bottom portion 3a of the yoke 3 with, for example, a spigot 31, and an annular fixing in which an adhesive (not shown) is applied. The outer periphery of the vibrating membrane 7 is directly fixed to the portion 3e, the supporting piece 3d and the pole piece 29 are covered with the vibrating membrane 7, and the voice coil 9 fixed to the vibrating membrane 7 is inserted between the pole piece 29 and the yoke 3. It is composed.

Reference numeral 33 in FIG. 7 denotes a circuit board to which an audio signal is externally supplied by the cable 15 (see FIG. 6). The audio signal is applied to the voice coil 9 from the circuit board 33 via a lead wire (not shown). It

In addition, a flexible adhesive (not shown) is applied to the inside of the front end of the front case 1b of the case body 1 and the space E on the back side of the annular fixing portion 3e of the yoke 3, so that the yoke 3, that is, the speaker body is attached to the front case 1b (main body case). It is fixed to 1).

However, in the configuration shown in FIG. 7, the vibrating membrane 7 is generally adhered and fixed to the annular fixing portion 3e with an adhesive, and when the speaker main body is inserted into the main body case 1, the annular fixing portion 3e. 3e is in contact with the step portion 1c of the front cover 1b so as to sandwich the vibrating membrane 7, and has the following problems.

That is, the vibrating film 7 is adhered to the annular fixing portion 3e with the above-described flexible adhesive in order to facilitate the vibration of the voice coil 9, and the adhering portion is attached to the step portion 1c of the front cover 1b. When they come into contact with each other, uneven pressing or bias due to a gap at the time of fitting is likely to occur, which causes deformation of the vibrating film 7, which becomes distortion at the time of vibration of the vibrating film 7 and tends to destabilize the characteristics.

The vibrating membrane 7 attached to the annular fixing portion 3e of the support piece 3d is cut from one large resin sheet to a diameter slightly larger than the outer diameter of the annular fixing portion 3e from the viewpoint of facilitating the attachment. Since it is attached to the annular fixing portion 3e, the outer peripheral edge of the vibrating membrane 7 protrudes from the annular fixing portion 3e to the outer periphery.

Therefore, the dimension S1 between the annular fixing portion 3e of the support piece 3d and the inside of the front case 1b of the case body 1 needs to be about 0.12 mm. From this point, the outer diameter dimension of the front case 1b, that is, the case body 1 is required. It tends to be an obstacle to miniaturization.

The above-mentioned problems are similarly applied to the outer magnet type structure, but the present inventor has found that the outer magnet type structure is a structure that can easily solve these problems, and completed the present invention.

The present invention has been made to solve such a problem, and an object of the present invention is to provide an electroacoustic transducer that can easily stabilize the characteristics and can be easily downsized.

In order to solve such a problem, the structure of the electroacoustic transducer of the present invention is a cylindrical magnetic yoke, and has a cylindrical tubular portion and one end face side of the tubular portion. from the flange portion is bent outwardly, and a yoke having, a one end surface is coaxially fixed to a ring-shaped drive magnet on its flange the inner circumference and the outer circumference of the tubular portion the in opposite surfaces a driving magnet facing circumferential spaced apart, and coaxially secured to a ring-shaped pole pieces and which on the other end face side of the drive magnet of that, and a driving magnet in the pole piece An attachment portion formed in an annular shape along the outer peripheral edge, an abutment portion formed concentrically with the attachment portion on the opposite surface of the pole piece outside the attachment portion, and the pole piece and the yoke are spaced apart from each other. And a thin vibrating membrane whose outer periphery is directly attached to the pasting portion so as to face each other, and a thin insulated conductive wire that is formed into a tubular shape and is fixed to one side of the vibrating membrane on the yoke side. , A voice coil that is inserted into an annular space between the inner circumference of the pole pieces and the outer circumference of the cylindrical portion and vibrates the vibrating membrane by an applied audio signal, and the inner wall contacts the contact portion. And a case main body for accommodating the pole pieces, the drive magnet and the yoke.

The configuration according to the electroacoustic transducer of the present invention may have a configuration in which the pasting portion is formed so as to project in a convex shape over the entire circumference of the outer peripheral edge portion of the pole piece.

The electroacoustic transducer of the present invention may have a configuration in which the abutting portion is formed so as to extend at a level lower than the affixing portion at the outer peripheral edge portion of the pole piece.

The electroacoustic transducer of the present invention may have a configuration in which the abutting portion is formed to extend at the same level from the affixing portion on the outer peripheral edge portion of the pole piece.

In the configuration according to the electroacoustic transducer of the present invention, the abutting portion is formed so as to extend on the outer peripheral edge portion of the pole piece via an annular groove formed along the outside of the affixing portion. Different configurations are also possible.

The electroacoustic transducer of the present invention may have a configuration in which the pole piece is made of a magnetic material.

In the configuration according to the electroacoustic transducer of the present invention, the ring-shaped driving magnet and the pole piece are fitted and fixed to the flange portion on the outer periphery of the yoke having the flange portion, and the outer peripheral edge portion of the pole piece is , A ring-shaped sticking part and a contact part on the outside of the sticking part are concentrically provided, and the vibrating film is stuck to the sticking part so as to block the pole pieces and the flange part, and fixed to the vibrating film. Since the coil is inserted between the pole piece and the yoke, it is easy to reduce the stress on the vibrating film attached to the pole piece, it is easy to suppress variations in characteristics and stabilize it, and it is easy to downsize. is there.

In the configuration according to the electroacoustic transducer of the present invention, the vibrating membrane can be easily placed and fixed on the sticking portion by forming the sticking portion so as to project in a convex shape over the entire outer peripheral portion of one surface of the pole piece.

In the configuration according to the electroacoustic transducer of the present invention, if the contact portion is extended on the outer peripheral portion of the pole piece at a level lower than the sticking portion, the contact portion can be made slightly thinner.

In the configuration of the electroacoustic transducer of the present invention, the shape of the flange portion can be simplified by extending the abutting portion at the same level from the affixing portion on the outer peripheral portion of the pole piece.

In the configuration according to the electroacoustic transducer of the present invention, if the abutting portion is provided on the outer peripheral portion of the pole piece via the annular groove formed along the outside of the affixing portion, Easy to place and fix the vibrating membrane on the attachment part.

In the configuration according to the electroacoustic transducer of the present invention, if the flange portion is made of a magnetic material, a strong magnetic circuit is formed between the pole piece and the yoke due to a reduction in leakage magnetic flux and a reduction in reactive magnetic flux. It is easy to secure vibration with quick response and effective damping.

It is a principal part longitudinal cross-sectional view which shows embodiment which concerns on the electroacoustic transducer of this invention. It is a partial expanded sectional view which expands and shows the principal part of the electroacoustic transducer of this invention. FIG. 2 is a bottom view of a vibrating membrane according to the electroacoustic transducer of FIG. 1. It is a schematic longitudinal cross-sectional view showing the electroacoustic transducer of FIG. 1 as an earphone device. It is a principal part longitudinal cross-sectional view which shows other embodiment which concerns on the electroacoustic transducer of this invention. It is sectional drawing which shows the conventional electroacoustic transducer with an example of use. FIG. 7 is a reference vertical sectional view for explaining the electroacoustic transducer of FIG. 6.

Hereinafter, an embodiment of an electroacoustic transducer according to the present invention will be described with reference to the drawings, taking a speaker device, for example, an earphone device as an example.

FIG. 1 is a longitudinal sectional view of an essential part showing an embodiment of a speaker device of the present invention.
In FIG. 1, a yoke 35 is formed of a magnetic plate material into a cylindrical shape, and is formed by bending the cylindrical portion 35a and one (lower side in FIG. 1) open end outward. It integrally has a plate-shaped flange portion 35b.

A ring-shaped drive magnet 37 is coaxially fitted to the outer periphery of the yoke 35 at a distance from the outer periphery of the cylindrical portion 35a, and one end face (lower side in FIG. 1) is superposed on the flange portion 35b. And it is fixed on this.

On the other end surface (upper side in FIG. 1) of the drive magnet 37, a pole piece 39 formed of a magnetic material in a ring plate shape and having an inner diameter substantially the same as or slightly smaller than the outer diameter of the drive magnet 37 is superposed. Has been. The pole piece 39 forms a magnetic circuit with the yoke 35.

The flange portion 35b, the drive magnet 37, and the pole piece 39 have the same outer diameter dimension, and both the inner circumference of the pole piece 39 and the drive magnet 37 projecting inward are substantially the same.

The pole piece 39 is located at substantially the same level as the other tip portion (upper side in FIG. 1) of the yoke 35, and faces the yoke 35 in the circumferential direction.

A circuit board 41 having a central through hole 41a and a plurality of through holes 41b surrounding the central through hole 41a is stacked on the outside of the flange portion 35b of the yoke 35 (the lower surface in FIG. 1).

The drive magnet 37, the pole piece 39, and the circuit board 41 are coaxially integrated with the flange portion 35b by an adhesive, for example, and are fixed to the flange portion 35b of the yoke 35.

As shown in FIG. 2A, a sticking portion 39a is integrally formed on the outer peripheral edge of the pole piece 39 on the side opposite to the drive magnet 37 so as to form a convex shape along the entire circumference along the outer circumference. In addition, the contact portion 39b is concentrically formed on the outer periphery of the sticking portion 39a on the opposite surface.

Since the sticking portion 39a of the pole piece 39 is projected in a convex shape, the abutting portion 39b is in a state of being extended and formed at a level lower than the sticking portion 39a. The contact portion 39b is brought into contact with the case main body 51 described later.

As shown in FIG. 3 from the pole piece 39 side, the vibrating film 43 is formed in a disk shape from a conventionally known thin insulating film material, and a relatively wide central portion is slightly swelled in a dome shape. It has a central region 43a and an outer peripheral region 43b which is concentrically and annularly surrounded by the central region 43a and slightly bulges out. Reference numeral 45a in FIG. 3 is a lead wire at both ends of the voice coil 45 described later.

Although not shown, a bent portion formed by bending a film material by providing a folded shape, a radial rib, or a concentric circular rib is formed in the central region 43a of the vibrating film 43, and the central region 43a has rigidity so that it is difficult to bend. ing.

Although not shown, the outer peripheral region 43b is formed with fine radial ridges and grooves called a so-called corrugation edge, and the outer peripheral region 43b is easily bent and easily vibrated in comparison with the central region 43a. Greater flexibility.

That is, the central region 43a is less likely to bend than the outer peripheral region 43b and has a high rigidity. However, it is important to be within a rigidity range in which good vibration of the vibrating membrane 43 including the central region 43a is ensured.

As shown in FIG. 1, the vibrating film 43 covers the yoke 35 and the pole piece 39 with a space therebetween, and overlaps the entire outer edge of the outer peripheral region 43b with the attaching portion 39a. It is adhesively fixed to the attaching part 39a by (not shown).

At the side of the yoke 35 of the vibrating membrane 43 (the lower surface side in FIG. 1), at the annular boundary between the central region 43a and the outer peripheral region 43b, one end face side of the cylindrical voice coil 45 is fixed so as to surround the central region 43a. Has been done.

The voice coil 45 is formed by winding a thin insulated conductive wire, which has been insulation-coated, in a cylindrical shape to be integrated, and between the outer circumference of the tubular portion 35 a of the yoke 35 and the inner circumference of the drive magnet 37 and the pole piece 39. The yoke 35 and the drive magnet 37 and the pole piece 39 are inserted at a slight interval, and face each other annularly between the outer circumference of the yoke 35 and the inner circumference of the drive magnet 37 and the pole piece 39.

The lead wire 45a from the voice coil 45 is led out from its diagonal position, is led out through the hollow portion of the yoke 35, and further through the through hole 41b of the circuit board 41, and is connected to the circuit board 41.

The through hole 41b is sealed with an adhesive tape or an adhesive after passing the lead wire 45a.

An audio signal is supplied from a electronic device (neither is shown) by a cable to the circuit board 41 stacked on the flange portion 35a of the yoke 35.

When the voice signal is applied to the voice coil 45, the voice coil 45 is displaced and the vibrating membrane 43 is vibrated.

That is, the yoke 35, the drive magnet 37, the pole piece 39, and the voice coil 45 form a drive portion 47 that vibrates and drives the vibrating film 43, and is a main portion (speaker body) of a so-called outer magnet type speaker device. ..

Reference numeral 49 in FIG. 1 is a breathable net for acoustic braking that closes the through hole 41a of the circuit board 41, and is formed of, for example, a non-woven fabric. It is possible to adjust the sound quality by changing the amount of ventilation between and.

In the speaker body of the outer magnet type speaker device, as shown in FIG. 4, the sticking portion 39a and the contact portion 39b of the pole piece 39 are fitted in the cap-shaped case body 51 and supported in the case body 51. There is.

The case main body 51 described above is made up of a large-diameter cylindrical portion 51a into which the outer peripheries of the yoke 35, the drive magnet 37, and the pole piece 39 are fitted, and a large-diameter cylindrical portion 51a that is continuous and is smaller in diameter than the yoke 35. It has a tubular portion 51b and is integrally molded from synthetic resin or the like.

The yoke 35, the drive magnet 37, and the pole piece 39 are integrated and fitted into the large-diameter cylindrical portion 51a, and the inner stepped portion 51c formed to reduce the inner diameter of the large-diameter cylindrical portion 51a has a pole. The contact portion 39b of the piece 39 is in contact.

That is, the outer peripheral edge portion of the pole piece 39 causes the fixed portion of the vibrating membrane 43 and the contact portion to the case body 51 to function individually in different portions.

After inserting the main part of the outer magnet type speaker device into the case main body 51, an adhesive agent (not shown) is provided in the rear side space formed between the rear side of the flange portion 35b and the inner wall of the case main body 51 (large-diameter cylindrical portion 51a). And the yoke 35 and the like are fixed to the case body 51.

The small-diameter cylindrical portion 51b of the case main body 51 covers the vibrating film 43 with a space therebetween, and also extends so as to project upward in FIG. 4 to form a sound passage cylindrical body.

In the speaker device configured as described above, the open front end of the cap-shaped cover 53 is press-fitted inside the open front end of the large-diameter cylindrical portion 51a of the case body 51, and the cover 53 is formed into a large-diameter cylindrical shape with an adhesive (not shown). It is fixed to the open (end) side of the portion 51 a, and the yoke 35 and the circuit board 41 are covered with a cover 53.

A flexible ear tip 55 is fitted on the outer circumference of the small-diameter tubular portion 51b, and is commercialized as an earphone device.

In such a speaker device, by supplying the audio signal from the cable through the circuit board 41 and applying the audio signal to the voice coil 45, the driving unit 47 vibrates and sounds the vibrating membrane 43, and the sound passage tube body is formed. The vibrating sound is propagated to the outside through the reduced small-diameter tubular portion 51b.

As shown in FIG. 6 described above, the speaker device according to the present invention stores the case main body 45 in the concha of the concha 25 surrounded by the tragus 19, the antitragus 21, and the concha 23. The ear tip 55 at the tip is inserted into the external auditory meatus 27 for use.

In such a configuration according to the speaker device of the present invention, since the outer peripheral edge portion of the pole piece 39 causes the fixed portion of the vibrating membrane 43 and the contact portion to the case main body 51 to individually function as separate portions, Even if the stepped portion 51c of the case main body 51 comes into contact with the contact portion 39b of the pole piece 39, uneven attachment of the vibrating membrane 43 to the attachment portion 39a or unevenness due to a gap during fitting is unlikely to occur. In addition, the stress on the vibrating film 7 is reduced to prevent the deformation of the vibrating film 7, and the distortion of the vibrating film 7 during vibration is easily suppressed to stabilize the characteristics.

Further, in the configuration according to the speaker device of the present invention, the above-mentioned pasting portion 39a is formed so as to project in a convex shape over the entire circumference of the outer peripheral edge portion of the pole piece 39, and this serves as positioning means and the vibrating membrane 43. Can be easily placed and fixed on the sticking portion 39a.

Further, in the configuration according to the speaker device of the present invention, the abutting portion 39b is extended on the outer peripheral edge portion of the pole piece 39 at a level lower than the attaching portion 39a, and is provided on the inner wall step 51c of the case body 51. Since it abuts, it is easy to reduce the thickness.

When the present invention is carried out with the insertion type earphone shown in FIG. 6, the outer peripheral portion is formed thin, so that the wearability to the ear is significantly improved. Helps reduce pain or pressure.

Moreover, since the contact portion 39b is provided on the outer periphery of the sticking portion 39a for fixing the vibrating membrane 43, even if the vibrating membrane 7 is larger than the outer diameter of the sticking portion 39a and the vibrating membrane 7 protrudes from the sticking portion 39a. It is easy to make the gap (corresponding to the symbol S1 in FIG. 7) between the sticking portion 39a and the large-diameter cylindrical portion 51a as small as possible, for example, about 0.05 mm.

Therefore, the present invention can contribute to a large reduction in the defect rate, prevention of performance variation, and higher performance without significantly changing the outer diameter dimension of the conventional outer magnet type product.

In addition, the pole piece 39 is made of a magnetic material, a strong magnetic circuit is formed between the pole piece 39 and the yoke 35, and there is an advantage that damping and a quick response vibration can be easily secured.

In this regard, in the conventional configuration, due to the gap S1 in FIG. 7, the eccentricity at the time of speaker insertion, the variation of the pressing force at the time of the insertion, the variation of the adhesive layer thickness, the variation of the adhesive protrusion, the variation of the vibrating film protrusion, etc. Many factors have caused performance failures.

In the present invention, the gap between the inner side of the large-diameter cylindrical portion 51a and the outer edge portion (contact portion 39b) of the pole piece 39 in FIG. 1 can also be made as small as 0.05 mm or less. This will cause a large drop in performance defects.

The speaker device according to the present invention may have a configuration other than the above-described configuration, for example, the configuration shown in FIG. 2B.

In FIG. 2B, an abutting portion 39c is planarly formed on the outer peripheral edge portion of the pole piece 39 from the attaching portion 39a at the same level.

Moreover, the contact portion 39c is formed so as to extend to the outside of the attaching portion 39a via an annular groove 39d formed along the contact portion 39a. That is, the attachment portion 39a, the concave groove 39d, and the contact portion 39c are continuously formed in a concentric shape.

The abutting portion 39c can be formed on the outer peripheral edge of the pole piece 39 having the same thickness, outside the affixing portion 39a, or on the same level surface as the affixing portion 39a protruding in a convex shape as shown in FIG. 2A. It is also possible to form. In the latter configuration, the thickness of the outer peripheral edge portion of the pole piece 39 is slightly increased.

2B, the yoke 35 and the peel piece 39 are fitted in the case body 51, and referring to FIG. 4, the abutting portion 39c of the pole piece 39 is attached to the inner wall of the case body 51. The yoke 35 is supported and fixed in the case main body 51 by being brought into contact with the stepped portion 51c of FIG.

The configuration of FIG. 2B is substantially the same as that of FIG. 4 except for the contact portion 39c and the concave groove 39d, and thus detailed illustration and description thereof will be omitted.

In the configuration related to the speaker device shown in FIG. 2B, in addition to the effect obtained from the configuration shown in FIG. 2A, the contact portion 39c is extended from the pasting portion 39a at the same level in the outer peripheral edge portion of the pole piece 39. The pole piece 39 can be simplified in shape and thin.

Further, since the abutting portion 39c is provided on the outer peripheral edge portion of the porcelain 39 via the annular concave groove 39d formed along the outside of the affixing portion 39a, the vibrating film 43 is formed. It is easy to place and fix on the sticking portion 39b.

Moreover, in practical use, the concave groove 39d has an advantage that it serves as a buffer band that clearly separates the attaching portion 39a and the contact portion 39c.

In addition, FIG. 5 is a longitudinal cross-sectional view of a main part showing another embodiment of the present invention.
In this structure, a plurality of protrusions 35c are provided on the inner wall of the tubular portion 35a of the yoke 35 so as to be dispersed at the same level position in the circumferential direction, and have the same function as the circuit board 41 of FIG. The circuit board 57 is inserted into the hollow portion from the lower side of the tubular portion 35a and brought into contact with the protrusion 35c, and the circuit board 41 is fixed to the protrusion 35c with an adhesive (not shown) or the like to be inserted into the hollow portion of the yoke 35. It is fixed.

A through hole 57a similar to the through hole 41a is formed in the center of the circuit board 57, and the through hole 57a is closed by the breathable net 49 described above.

Further, the outer diameter of the pole piece 39 is made larger than that of the drive magnet 37 and the flange portion 35b, or the outer diameter of the drive magnet 37 and the flange portion 35b is made smaller than that of the pole piece 39. Is projected in the outer peripheral direction from the drive magnet 37 and the flange portion 35b. Illustration of the case body 51 is omitted.

Note that, in FIG. 5, the configuration other than the yoke 35, the pole piece 39, and the circuit board 57 is almost the same as that in FIGS. 1 and 4, and thus detailed illustration and description thereof will be omitted.

In the configuration shown in FIG. 5, the circuit board 57 is housed in the hollow portion of the yoke 35, and the circuit board 57 is supported and housed inside the yoke 35 by the plurality of projections 35c. In addition, it can be made thinner.

By the way, in the speaker device of the present invention, in addition to the configuration in which the sound passage tubular body formed by the small-diameter tubular portion 51b of the case body 51 is projected along the central axis of the case body (small-diameter tubular portion) 51, A configuration that projects in an oblique direction with respect to is also possible.

The electroacoustic transducer of the present invention can be widely used as a headphone, a speaker device such as a large speaker, and a microphone.

1, 51 Case body 1a Base part 1b Front cover 1c, 51c Step part 3, 35 Yoke 3a Bottom parts 3b, 41a, 41b, 57a Through hole 3c, 35a Cylindrical part 3d Supporting piece 3e Annular fixing part 5, 37 Driving magnet 7, 43 Vibration film
9,45 Voice coil 11 Sound passage cylinder 13,55 Ear tip (ear pad, ear piece)
15 cable 15a knot 17, 47 drive unit 19 tragus 21 antitragus 23 concha 25 concha cavity 27 ear canal 29, 39 ear piece 29, pole piece 31 stop 33, 41, 57 circuit board 35b flange 35c protrusion 39a sticking portion 39b , 39c Abutting portion 39d Recessed groove 43a Central region 43b Outer peripheral region 45a Both ends lead wire 49 Breathable net 51a Large diameter tubular portion 51b Small diameter tubular portion 53 Cover E Rear side space

Claims (6)

A cylindrical magnetic material of the yoke, the yoke having a cylindrical tubular portion, one, and a flange portion is bent outwardly from the end face side of said cylindrical portion,
A ring-shaped drive magnet, one end surface of which is coaxially fixed to the flange portion, wherein the inner periphery faces the outer periphery of the tubular portion with a space therebetween ,
And coaxially fixed to a ring-shaped pole pieces and which on the other end face side of the front SL drive magnet,
An attachment portion formed in an annular shape along the outer peripheral edge portion on the surface of the pole piece opposite to the drive magnet,
An abutting portion concentrically formed on the opposite side of the pole piece on the outer side of the pasting portion,
A thin vibrating film whose outer periphery is directly attached to the attaching portion so as to face the pole piece and the yoke with a space therebetween,
A voice coil, which is formed into a tubular shape by winding a thin insulated wire and is fixed to one side surface of the yoke of the vibrating membrane, wherein an annular gap is provided between the inner periphery of the pole piece and the outer periphery of the tubular portion. A voice coil that vibrates the vibrating membrane according to a voice signal applied to the vibrating membrane,
A case body for housing the pole piece, the drive magnet, and the yoke by bringing the inner wall into contact with the contact portion;
An electroacoustic transducer comprising: The electroacoustic transducer according to claim 1, wherein the attaching portion is formed so as to protrude in a convex shape over the entire circumference of the outer peripheral edge portion of the pole piece. The electroacoustic transducer according to claim 1 or 2, wherein the abutting portion is formed so as to extend at a level lower than the affixing portion in the outer peripheral edge portion of the pole piece. The electroacoustic transducer according to claim 1 or 2, wherein the abutting portion is formed to extend at the same level from the affixing portion in the outer peripheral edge portion of the pole piece. The electroacoustic transducer according to claim 4, wherein the abutting portion is formed on the outer peripheral edge of the pole piece so as to extend to the outside of the affixing portion via an annular groove formed along the abutting portion. The electroacoustic transducer according to claim 1, wherein the pole piece is made of a magnetic material.

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