KR101738135B1

KR101738135B1 - Balanced armature unit and manufacturing method the same

Info

Publication number: KR101738135B1
Application number: KR1020150180292A
Authority: KR
Inventors: 최상수; 홍준표; 고주헌; 백대선; 김성용; 김동원; 김남서
Original assignee: 주식회사 알머스; 싸니코전자 주식회사
Priority date: 2015-12-16
Filing date: 2015-12-16
Publication date: 2017-06-22

Abstract

The present invention relates to an electric motor comprising a bottom portion provided with a power supply member, an operation portion having an armature, a shaft, a magnet, a yoke and a coil electrically connected to the power supply member, And a vibration plate assembly which is joined to the shaft and receives the vibration of the armature through the shaft, and a sound hole at a predetermined portion of the upper surface, the vibration plate assembly being opened downward, And a cover portion joined on the bottom portion, and a method of manufacturing the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a balanced armature unit,

The present invention relates to a balanced armature unit and a method of manufacturing the same, and more particularly to a balanced armature unit including a bottom portion of an insulating material and a sound hole not protruding from the cover portion to improve the downsizing and productivity of the product. And a method for producing the same.

With the miniaturization of electronic devices, products equipped with audio functions such as smart phones, MP3 players, and PMPs are spreading. These electronic devices often use earphones to connect them to listen to voice or music. Accordingly, attempts have been made in the past to improve the appearance convenience, aesthetic design, and sound quality of the earphone.

Among them, one of the new speaker technologies for reproducing the sound quality of the earphone as close to the original sound as possible is called a balanced armature (BA) as described in Korean Patent Laid-Open Publication No. 2014-0038232. This technology was originally introduced decades ago and is a technology that has been used in hearing aids, and has recently been used in earphones.

However, in the balanced amateur technique proposed in the above patent, since the housing serving as a supply passage for supplying external power to the coil is formed of a metal material, it is difficult to assemble the housing with the drive module, which is a magnetic body, .

In addition, since the connection mode is formed separately from the drive module, and the process of joining the connection mode and the drive module is further performed, the vibration module receives the vibration of the drive module due to external influences such as noise due to the joint portion, There is a problem that the reliability of the product is deteriorated, the process is complicated, and the productivity of the product is deteriorated.

Further, since the discharge port, which is the discharge passage of the sound of the vibration module, is formed by protruding from the housing, there is a problem that the miniaturization of the product is lowered.

KR 10-2014-0038232 A

It is an object of the present invention to improve the miniaturization and productivity of a product by including a sound hole which is formed of an insulating material including a power supply member for supplying external power to the coil and does not protrude from a cover portion bonded on the bottom portion To provide a balanced amateur unit and a manufacturing method thereof.

A balanced armature unit according to the present invention includes a bottom portion provided with a power supply member, a coil portion disposed and bonded to the top portion of the bottom portion and having an armature, a shaft, a magnet, a yoke, and a coil electrically connected to the power supply member A vibrating plate assembly which is joined to the shaft and receives the vibration of the armature through the shaft, and a sound hole at a predetermined portion of the upper surface, the vibrating plate assembly being opened downward, And a cover portion joined to the bottom portion so as to accommodate the bottom portion.

Further, the shaft may be combined with the armature.

Further, the sound hole may be positioned above the diaphragm assembly so that the sound generated from the diaphragm assembly is emitted to the outside.

In addition, the bottom portion may be formed of an epoxy material to facilitate assembly with the operation portion and the cover portion.

The amateur is formed in a "C" shape comprising a bottom plate joined to the top surface of the bottom portion, a support plate formed upward in one end of the bottom plate, and a central stone plate formed in the horizontal direction on the bottom plate from the top of the support plate And a yoke guide plate formed upward in each of opposite ends of the opposite end of the lower plate to fix the yoke.

The armature is formed such that the width of the lower plate between the yoke guide plate and the support plate is narrower than the width of the lower plate on which the yoke guide plate is formed such that the power supply member is exposed when the armature is joined to the bottom portion .

The yoke may include a guide engaging portion that is recessed inwardly in correspondence with the yoke guide plate at lower portions of both sides of the yoke so as to be fixed to the armature.

Further, the actuating portion may be configured such that the coil surrounds the central protrusion plate between the yoke guide plate of the armature and the support plate, the magnet is composed of the first magnet and the second magnet, and is inserted into the upper and lower surfaces of the yoke, The yoke may be fixed to the yoke guide plate so as to surround the central protrusion on one side of the coil and the lower plate of the armature may be joined to the upper surface of the bottom portion and disposed on the bottom portion.

Further, the shaft may be integrally formed with the armature.

The shaft may be integrally formed from the end of the central protrusion plate on the upper side of the yoke guide plate of the armature, and the coil and the yoke may be bent upward to surround the central protrusion plate and be connected to the diaphragm assembly have.

The diaphragm assembly may further include a frame joined to an inner upper surface of the cover portion where the sound hole is formed, a film bonded to a bottom edge of the frame and supported by the frame, And may include a plate that is joined to the shaft.

In addition, the sound hole may be a hole formed in a predetermined portion of the upper surface of the cover portion, and may not protrude upward.

And the combination with the manufacturing method of the balanced armature unit of the present invention includes the steps of having a sound hole in a predetermined portion of which includes the power supply member bottom (bottom) portion and a top surface and provided parts of the opening cover downwardly, armature, the armature A step of disposing and joining an actuating part having a shaft , a magnet, a yoke and a coil electrically connected to the power supply member on the bottom part, and a diaphragm assembly receiving the vibration of the armature through the shaft Joining the diaphragm assembly to a shaft bent in an upward direction of the armature, and attaching the cover portion on the bottom portion so that the actuating portion and the diaphragm assembly are received, And joining.

The step of arranging and joining the actuating part on the bottom part comprises joining the yoke to one side of the coil and inserting and coupling the first magnet and the second magnet constituting the magnet into the upper and lower surfaces of the opened yoke, The yoke is fixed to the yoke guide plate of the armature so that the coil and the yoke sequentially pass the central protrusion to the coil and the yoke so as to surround the central protrusion of the armature, It is possible to join the lower plate of the second plate.

According to the balanced amateur unit and the method of manufacturing the same according to the embodiment of the present invention, the bottom portion including the power supply member for supplying the external power to the coil is formed of the epoxy material so that the bottom portion is made of the amorphous material, And the cover part for housing and covering the operation part can be easily assembled, thereby improving the reliability and productivity of the product.

According to the balanced amateur unit and the method of manufacturing the same according to the embodiment of the present invention, the armature includes the yoke guide plate and the yoke includes the guide coupling portion, and the yoke is fixed to the armature through the yoke guide plate and the guide coupling portion, And assembling between the armature and the yoke is easier than in the case where the guide coupling portion is not formed, thereby improving the reliability and productivity of the product.

According to the balanced amateur unit and the method of manufacturing the same according to the embodiment of the present invention, since the shaft is formed integrally with the armature, the shaft is formed separately from the armature, and the vibration of the armature Can be transmitted to the diaphragm assembly without any external influence such as noise, thereby improving the reliability of the product, simplifying the process, and improving the productivity of the product.

Further, according to the balanced amateur unit and the manufacturing method thereof according to the embodiment of the present invention, since the film of the diaphragm assembly is not deformed as the frame supports the film by including the frame supporting the film, The sound quality generated from the diaphragm assembly can be improved and the life of the product can be prolonged.

In addition, according to the balanced amateur unit and the manufacturing method thereof according to the embodiment of the present invention, by including the sound hole formed in the cover portion without protruding from the cover portion, it is possible to improve the miniaturization of the product more than when the sound hole protrudes from the housing .

1 is a perspective view showing a balanced armature unit according to an embodiment.
2 is an exploded perspective view of FIG.
3 is a cross-sectional view of Fig.
4 is a view showing a method of manufacturing a balanced armature unit according to an embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art, and the following embodiments may be modified in various other forms, The present invention is not limited to the following embodiments. Rather, these embodiments are provided so that this disclosure will be more thorough and complete, and will fully convey the concept of the invention to those skilled in the art.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an," and "the" include plural forms unless the context clearly dictates otherwise. Also, " comprise "and / or" comprising "when used herein should be interpreted as specifying the presence of stated shapes, numbers, steps, operations, elements, elements, and / And does not preclude the presence or addition of one or more other features, integers, operations, elements, elements, and / or groups. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items.

Although the terms first, second, etc. are used herein to describe various elements, regions and / or regions, it should be understood that these elements, components, regions, layers and / Do. These terms do not imply any particular order, top, bottom, or top row, and are used only to distinguish one member, region, or region from another member, region, or region. Thus, the first member, region or region described below may refer to a second member, region or region without departing from the teachings of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings schematically showing embodiments of the present invention. In the figures, for example, variations in the shape shown may be expected, depending on manufacturing techniques and / or tolerances. Accordingly, embodiments of the present invention should not be construed as limited to any particular shape of the regions illustrated herein, including, for example, variations in shape resulting from manufacturing.

Fig. 1 is a perspective view showing a balanced armature unit according to an embodiment, Fig. 2 is an exploded perspective view of Fig. 1, and Fig. 3 is a sectional view of Fig.

1 and 3, the balanced armature unit 100 according to the embodiment includes a bottom portion 10 provided with a power supply member 11, And includes an operating portion 30 having an armature 31, a shaft 33, a magnet 35, a yoke 37, and a coil 39 electrically connected to the power supply member 11, A diaphragm assembly 50 which is joined to the shaft 33 and receives the vibration of the armature 31 through the shaft 33 and a sound hole 71 formed in a predetermined portion of the upper surface, And a cover portion 70 that is joined on the bottom portion 10 to receive the diaphragm assembly 30 and the diaphragm assembly 50. Here, the sound hole 71 is positioned above the diaphragm assembly 50 so that the sound generated from the diaphragm assembly 50 is radiated to the outside.

The bottom portion 10 is formed of an epoxy material. The power supply member 11 is for supplying an external power source to the coil 39. In addition, a coupling pattern 13 may be formed on the top surface of the bottom portion 10 so that the armature 31 is seated and engaged.

As described above, in the balanced amateur unit 100 according to the embodiment, since the bottom portion 10 including the power supply member 11 for supplying external power to the coil 39 is formed of an epoxy material, The bottom portion 10 can be more easily assembled with the operation portion 30 and the cover portion 70 than the conventional one using the formed lower cover.

The operation portion 30 is configured such that the coil 39 surrounds the central protrusion 315 between the yoke guide plate 317 and the support plate 313 of the armature 31 to be described later, And the lower plate 311 of the armature 31 to be described later is joined to the upper surface of the bottom portion 10 so as to be fixed on the bottom portion 10 Arranged and bonded.

The armature 31 is formed of a magnetic material and vibrates according to the change of the magnetic field caused by the coil 39 and the magnet 35. The armature 31 includes a lower plate 311 joined to the upper surface of the bottom portion 10, a support plate 313 extending upward from one end of the lower plate 311, a lower plate 311 extending from the upper end of the support plate 313, And is formed in a shape of a letter "C" consisting of a central projection 315 extending in the horizontal direction and formed upward in each of opposite ends opposite to one end of the lower plate 311, Plate 317 as shown in FIG.

The armature 31 has a width of a lower plate 311 on which the coil 39 is positioned to expose the power supply member 11 when the armature 31 is joined to the bottom portion 10, The width of the lower plate 311 between the lower plate 317 and the support plate 313 is narrower than the width of the lower plate 311 where the yoke guide plate 317 is formed.

The shaft 33 extends integrally from the end of the central protrusion 315 on the yoke guide plate 317 of the armature 31. At this time, the shaft 33 surrounds the central protrusion 315 after the coil 39 and yoke 37 surround the diaphragm assembly 50 and is bent upward.

As described above, the balanced armature unit 100 according to the embodiment is configured such that the shaft 33 is formed separately from the armature 31 and the shaft 33 is formed separately from the armature 31 because the shaft 33 is formed integrally with the armature 31. [ The vibration of the armature 31 can be transferred to the diaphragm assembly 50 without any external influences such as noise and the process can be simplified as compared with the conventional art in which the process of joining the armature 31 is performed.

The shaft 33 may be formed integrally with the armature 31 as described above and combined with the armature 31 or may be combined with the armature 31 in various other combinations such as joining.

The shaft 33 is connected to the diaphragm assembly 50 so as to be easily joined to the diaphragm assembly 50. A horizontal joint surface 331 formed by bending one end of the shaft 33 to form a horizontally flat joint is formed .

The magnet 35 includes a pair of first magnets 351 inserted and coupled to the upper and lower inner surfaces of a yoke 37 to be described later and spaced apart from each other with respect to the central protrusion 315 of the armature 31, 2 magnets 353, as shown in FIG.

The yoke 37 surrounds the first magnet 351 and the second magnet 353. The central protrusion 315 of the armature 31 is inserted through the hollow space of the yoke 37 between the first magnet 351 and the second magnet 353 inserted into the upper and lower surfaces of the yoke 37, And can pass through the yoke 37.

The yoke 37 includes a guide engaging portion 371 which is recessed inwardly in correspondence with the yoke guide plate 317 of the armature 31 below the both sides so as to be fixed to the armature 31. [

As described above, in the balanced armature unit 100 according to the embodiment, since the armature 31 includes the yoke guide plate 317 and the yoke 37 includes the guide engaging portion 371, the yoke guide plate Assembling between the armature 31 and the yoke 37 may be easier than in the prior art which does not include the yoke 317 and the guide engaging portion 371.

One side of the yoke 37 is joined to the coil 39 and surrounds the central protrusion 315 of the armature 31. The yoke 37 supports the first magnet 351 and the second magnet 353, which are inserted into and coupled to the upper and lower inner sides, respectively, with the center stone plate 315 as a center. In particular, the yoke 37 supports the central stone plate 315 and the first magnet 331 and the second magnet 333 so as to have a predetermined gap therebetween.

One end of the coil 39 is connected to one surface of the yoke 37 and is fitted to surround the central protrusion 315 of the armature 31. The coil 39 is connected to the outside of the yoke 37 through the power supply member 11 of the bottom portion 10, Power is supplied.

The diaphragm assembly 50 is for reproducing sound by vibration or vibration of the armature 31. The diaphragm assembly 50 includes a frame 51 bonded to the inner upper surface of the cover 70 where the sound hole 71 is formed, A film 53 joined to the bottom edge surface of the film 51 and supported by the frame 51 and a plate 55 joined to the bottom of the film 53 and joined to the shaft 33.

As described above, in the balanced amateur unit 100 according to the embodiment, since the film 53 of the diaphragm assembly 50 is supported by the frame 51, the film 53 is not deformed, The sound quality generated from the diaphragm assembly 50 is improved and the lifetime of the balanced amateur unit can be extended.

The cover 70 is coupled to an upper surface of the bottom portion 10 to cover and receive the operation portion 30 and the diaphragm assembly 50 and includes a sound hole 71 formed at a predetermined portion of the upper surface . Here, the sound hole 71 may serve as a guide for guiding the sound generated from the diaphragm assembly 50 to be radiated to the outside. The sound hole 71 is formed on a predetermined portion of the upper surface of the cover portion 70 so as not to protrude upward of the cover portion 70.

As described above, since the balanced amateur unit 100 according to the embodiment is formed in the cover portion 70 without protruding from the cover portion 70, the sound hole 71 is formed in the conventional art in which the sound hole is protruded from the housing The size of the product can be further improved.

4 is a view showing a method of manufacturing a balanced armature unit according to an embodiment. Here, Fig. 4 includes Figs. 4A to 4E.

Hereinafter, a method of manufacturing a balanced armature unit according to an embodiment will be described in detail.

In order to manufacture the balanced amateur unit according to the embodiment, first, a bottom portion 10 having a power supply member 11, a cover portion 70 having a sound hole 71 at a predetermined position on its upper surface and opened downward, .

Thereafter, the operating portion 30 including the armature 31, the shaft 33, the magnet 35, the yoke 37, and the coil 39 connected to the power supply member 11 is mounted on the bottom portion 10 Respectively. Here, the shaft 33 extends horizontally from the end of the central protrusion 315 of the armature 31 to the central protrusion 315 and is integrally formed with the armature 31.

4A, the other side of the coil 39 and the other side of the yoke 37 are joined to each other, and the yoke 37 is disposed so as to be spaced apart from each other with respect to the central protrusion 315 of the armature 31, The first magnet 351 and the second magnet 353 are inserted and coupled to the inner and outer surfaces of the first magnet 351 and the second magnet 353, respectively.

4B, the central protrusion 315 of the armature 31 has a central portion of each of the coil 39 and the yoke 37 into which the first and second magnets 351 and 353 are inserted, And the central stone plate 315 between the support plate 313 of the armature 31 and the yoke guide plate 317 is surrounded by the coil 39 and the center stone plate 315 And surrounds the publication 315 with the yoke 37. At this time, a yoke 37 is formed on the lower plate 311 of the armature 31 by engaging the yoke guide plate 317 with the guide engaging portion 371 formed corresponding to the yoke guide plate 317 below the yoke 37, .

The shaft 33 is bent so that the shaft 33 formed horizontally extended with the central projection 315 of the armature 31 is positioned on the upper side of the armature 31 as shown in Fig. Then, the upper surface of the bottom portion 10 and the bottom surface of the armature 31 are joined. The power supply member 11 of the bottom portion 10 and the coil 39 are electrically connected to each other so that the coil 39 is supplied with external power through the power supply member 11.

Subsequently, the diaphragm assembly 50 is joined to the upper inner surface of the cover portion 70 where the sound hole 71 is formed.

4D, the plate 55 is disposed on the lower surface of the film 53 and the upper surface of the film 53 opposed to the lower surface of the film 53 on which the plate 55 is disposed The lower end of the frame 51 is positioned and the film 53 and the frame 51 are joined together. The lower end of the frame 51 which is joined to the film 53 is joined to the lower inner surface of the cover 70 where the sound hole 71 is formed.

Thereafter, as shown in FIG. 4E, the plate 55 of the diaphragm assembly 50 is joined to the horizontal joint surface 331 of the shaft 33 positioned in the upward direction of the armature 31, The cover portion 70 is joined to the bottom portion 10 so that the diaphragm assembly 50 bonded to the actuating portion 30 and the shaft 33 is accommodated in the base portion 10 and 70.

In the balanced amateur unit 100 according to the embodiment manufactured by such a manufacturing method, the armature 31 is magnetized as a current by an external power source is applied to the coil 39. [

Then, the magnetized armature 31 moves and interacts with the magnetic field formed by the first magnet 351 and the second magnet 353.

That is, the degree of magnetization of the armature 31 varies according to the current flowing into the coil 39, and the magnetization of the armature 31 is formed by the magnetized amateur 31 and the magnet (i.e., the first and second magnets 351 and 353) The intensity of the force acting between the magnetic fields is changed, and the central projection 315 of the armature 31 vibrates.

The shaft 33 formed integrally with the armature 31 moves together with the oscillation of the central projection 315. Thus, the diaphragm assembly 50 joined to the shaft 33 receives vibration. Then, the diaphragm assembly 50 generates a sound in response to the transmitted vibration. The sound generated from the diaphragm assembly 50 is radiated to the outside through the sound hole 71 of the cover portion 70. [

As described above, the balanced amateur unit according to the embodiment of the present invention and the method of manufacturing the same have been described. However, it is apparent that various modifications are possible without departing from the scope of the present invention.

Therefore, the scope of the present invention should not be construed as limited to the embodiments described, but should be determined by the scope of the appended claims, as well as the claims.

It is to be understood that the foregoing embodiments are illustrative and not restrictive in all respects and that the scope of the present invention is indicated by the appended claims rather than the foregoing description, It is intended that all changes and modifications derived from the equivalent concept be included within the scope of the present invention.

10: Bottom part 11: Power supply member
30: Operation part 31: Amateur
33: shaft 35: magnet
37: yoke 39: coil
50: diaphragm assembly 51: frame
53: Film 55: Plate
70: cover part 71: sound hole
311: Lower part 313: Support plate
315: central stone publication 317: yoke guide plate
331: Horizontal joint surface 351: First magnet
353: second magnet 371: guide coupling portion

Claims

A bottom portion provided with a power supply member;
An operating portion disposed on and bonded to an upper surface of the bottom portion and having an armature, a shaft, a magnet, a yoke, and a coil electrically connected to the power supply member;
A diaphragm assembly connected to the shaft and receiving the vibration of the armature through the shaft; And
A cover portion having a sound hole at a predetermined portion of an upper surface thereof and opened downwardly and joined to the bottom portion to receive the operation portion and the diaphragm assembly; / RTI >
The shaft is coupled to the armature and the sound hole is radiated to the outside, the sound hole is located on the upper side of the diaphragm assembly,
The amateur,
A lower plate joined to the upper surface of the bottom portion, a support plate formed upward at one end of the lower plate, and a central stone plate formed at the upper end of the support plate in a horizontal direction on the lower plate, And a yoke guide plate which is formed upward in each of opposite sides of the opposite end and fixes the yoke.

2. The apparatus according to claim 1,
And is formed of an epoxy material so as to be easily assembled with the operation portion and the cover portion.

delete

The apparatus of claim 1, wherein the amateur comprises:
Wherein a width of the lower plate between the yoke guide plate and the support plate is narrower than a width of the lower plate on which the yoke guide plate is formed such that the power supply member is exposed when the armature is joined to the bottom portion.

2. The yoke according to claim 1,
And a guide engaging portion that is recessed inwardly in correspondence with the yoke guide plate at lower portions of both sides of the yoke so as to be fixed to the armature.

The apparatus according to claim 1,
Wherein the yoke surrounds the central protrusion between the yoke guide plate of the armature and the support plate and the magnet is composed of a first magnet and a second magnet and is inserted into the upper and lower surfaces of the yoke, And a lower plate of the armature is joined to the upper surface of the bottom portion and is disposed on the bottom portion.

2. The apparatus of claim 1,
And a balanced amateur unit integrally formed with the armature.

2. The apparatus of claim 1,
And the yoke is integrally extended from an end of the central protrusion plate on the upper side of the yoke guide plate of the armature, and the coil and the yoke surround the central protrusion and are bent upward to be joined to the diaphragm assembly.

The apparatus of claim 1, wherein the diaphragm assembly comprises:
A frame joined to an inner upper surface of the cover portion where the sound hole is formed;
A film bonded to the bottom edge of the frame and supported by the frame; And
A plate joined to a lower portion of the film and joined to the shaft;
Gt; a < / RTI > balanced amateur unit.

The sound output apparatus according to claim 1,
And is not formed as a hole formed in a predetermined portion of the upper surface of the cover portion so as not to protrude upward.

Providing a bottom portion having a power supply member and a cover portion having a sound hole at a predetermined portion of an upper surface thereof and opening downward;
Disposing and joining an actuating part having an armature, a shaft coupled with the armature, a magnet, a yoke and a coil electrically connected to the power supply member on the bottom part;
Joining a diaphragm assembly receiving the vibration of the armature through the shaft to an upper inner surface of the cover portion where the sound hole is formed; And
Joining the diaphragm assembly to a shaft bent in an upward direction of the armature, and joining the cover section on the bottom section to receive the actuating section and the diaphragm assembly; / RTI >
The sound hole is positioned above the diaphragm assembly so that the sound generated from the diaphragm assembly is emitted to the outside,
The amateur,
A bottom plate joined to an upper surface of the bottom portion, a support plate formed on an upper end of the bottom plate, and a central projection formed horizontally on the bottom plate at an upper end of the support plate, And a yoke guide plate for fixing the yoke upward from each of opposite sides of the opposite end portions.

12. The apparatus according to claim 11,
Wherein the cover is made of an epoxy material so as to be easily assembled with the operation part and the cover part.

delete

12. The apparatus of claim 11, wherein the amateur comprises:
Wherein a width of the lower plate between the yoke guide plate and the support plate is narrower than a width of the lower portion where the yoke guide plate is formed so that the power supply member is exposed when the armature is joined to the bottom portion .

12. The method according to claim 11,
And a guide engaging portion that is recessed inwardly in correspondence with the yoke guide plate at lower portions of both sides of the yoke so as to be fixed to the armature.

12. The method of claim 11, wherein positioning and joining the actuating portion on the bottom portion comprises:
Wherein the yoke is coupled to one side of the coil and the first magnet and the second magnet constituting the magnet are inserted and coupled to the inside upper and lower surfaces of the opened yoke and the yoke is fixed to the yoke guide plate of the armature, The central protrusion being sequentially passed through the coil and the yoke so that the yoke surrounds the central protrusion of the armature, and the lower plate of the armature is joined to the upper surface of the bottom.

12. The method of claim 11,
Wherein the armature is formed integrally with the armature.

12. The method of claim 11,
And extending from an end of the central stone plate on the upper side of the yoke guide plate of the armature to integrally form the armature with the armature.

The method as claimed in claim 18, wherein, prior to joining the diaphragm assembly to the shaft after joining the diaphragm assembly to an upper inner surface of the cover,
And the shaft is bent upwardly of the armature.