JPS62193499A - Electroacoustic transducer - Google Patents

Abstract

PURPOSE:To eliminate a spark discharge from an electrified human body to a terminal part, by separating an acoustic space at the front plane of a diaphragm from a magnetic circuit and a conductive part, or making long a distance between them. CONSTITUTION:A baffle plate 21 molded with a material having a high magnetic permeability has a guide 34 fitting in the outer peripheral guide 33 of the diaphragm in a frame 28, and it is adhered with a fitting part, and also, the separation of the acoustic space at the front plane of a diaphragm 22 from the conductive part, such as a shield board that is also used as a terminal 29, etc., can be realized by packing the guide part 34 of the frame 28 having a notch with an adhesives to draw out a voice coil lead 24. The shield and terminal 29 made of the material having the high magnetic permeability, such as an iron, etc., molded at the baffle plate 21 has a vertical part extending to a plate 27 with a center pole at the outer periphery of a diaphragm guide part 33 in the frame 28, and constitutes a magnetic circuit 32 which induces a leakage magnetic flux to the front plane of a magnetic cavity 31 to the plate 27 with the center pole. In this way, when electrified object is approached to a unit, a discharge path is a path along the outside wall of the unit, and a breakdown can be prevented from being occurred.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electroacoustic transducer such as a speaker as a receiving unit and a microphone unit as a transmitting unit used in a telephone 2 communication device, etc. .

BACKGROUND ART FIG. 2 is a cross-sectional view of a configuration example of a conventional electrodynamic transmitting/receiving unit, in which 1 is a baffle plate, 2 is a diaphragm, 3 is a voice coil, 4 is a voice coil lead, 5 is a top plate, 6 is a magnet, 7 is a plate with a center pole, 8 is a frame, 9 is a terminal, and 1o is a back cover.

A top plate 6, a magnet 6, and a plate with a center pole 7 are combined to form a magnetic circuit with a concentric magnetic gap, and are combined inside a frame 8 made of resin or the like to form a housing assembly. . In addition, a voice coil 3 is bonded to a diaphragm 2 made of resin film to form a vibration system, and the peripheral part of the diaphragm 2 of this vibration system is bonded to the guide inner circumference of the frame 4 of the housing assembly, and the voice coil Connect the lead 4 to a terminal 9 provided on the frame 8. Furthermore, a baffle plate 1 made of molded resin with ventilation holes is placed in front of the diaphragm 2, and a buckle plate 1 is placed in front of the diaphragm 2.
and frame 8 are adhered, and furthermore, a back cover 1Q constituting an acoustic circuit is adhered to frame 8 to constitute an electroacoustic transducer as a speaker and microphone unit.

In the above configuration, the buckle plate 1 has a guide that fits with the diaphragm guide of the frame 8, and the fitting part is bonded, and the guide part of the frame 8 that is missing for pulling out the voice coil lead 4 Problems to be Solved by the Invention However, in the above-mentioned conventional configuration, the magnetic flux leaking to the front of the magnetic gap is separated from the acoustic space and the conductive part by filling it with adhesive or the like. When used as a handset for a telephone, etc., it leaks to the front of the mounting housing and attracts pins on a tabletop, making it dangerous for these units to be used close to the human body, especially the face. There is.

FIG. 3 is a cross-sectional view of another example of the configuration of an electroacoustic transducer as a conventional speaker and microphone unit.
1 is a front cover, 12 is a diaphragm, 13 is a voice coil,
14 is the voice coil lead, 16 is the top plate,
16 is a magnet, 1A is a plate with a center pole,
'BIr! - frame, 19 is a terminal, and 20 is a back cover.

As in FIG. 2, a top plate 15. Magnet 16. Plate with center pole 1
In the housing assembly which formed the magnetic circuit which combined 7,
A vibration system including a diaphragm 12 and a voice coil 13 is bonded together, and a voice coil lead 14 and a terminal 19 are connected. Further, a cover 11 molded from a high magnetic permeability material having ventilation holes is arranged on the front side of the diaphragm 12, and a back cover 20
is adhered to the frame 14 to constitute an electroacoustic transducer as a speaker and microphone unit.

In the above configuration, the cover 11 has a structure that constitutes a magnetic circuit from the front side of the magnetic gap to the plate 17 with a center pole, and the magnetic flux leaking from the front side of the magnetic gap passes through the cover 11 to the plate 17 with a center pole. Therefore, the leakage magnetic flux towards the front of the unit is reduced.

However, in the conventional configuration shown in FIG. 3, the acoustic space and the conductive part are not separated, and if the user's body is charged with static electricity, spark discharge will occur through the cover 11 to the terminal 19. In this case, since these units are used as telephones and communication devices in a near-field sound field, the discharge occurs near the human mouth and ears, and is extremely unpleasant and dangerous.

The present invention solves the above-mentioned conventional problems, and aims to reduce leakage magnetic flux and separate the acoustic space and the conductive part in the same unit, and prevents pins etc. from being attracted by the leakage magnetic flux and spark discharge from a charged human body. The purpose of the present invention is to provide an electroacoustic transducer that is free from discomfort and danger.

Means for Solving the Problems In order to achieve the above object, the present invention provides a backful plate with a three-layer structure of an insulating material, a high magnetic permeability material, and an insulating material, and the high magnetic permeability material is used as a plate with a center pole. The structure uses a magnetic circuit that is routed to near the outer edge of the magnetic gap and directs leakage magnetic flux toward the front surface of the magnetic gap toward the plate with the center pole.

Effect The above configuration reduces magnetic flux leakage to the front of the unit, and also separates conductive parts such as the magnetic circuit and terminals from the acoustic space using the structure of the frame and baffle plate, or increases the distance between them and prevents charged human bodies. Spark discharge can be further eliminated.

Example An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a structural sectional view of an electroacoustic transducer that can be used as a speaker and microphone unit in an embodiment of the present invention, in which 21 is a baffle plate, 22 is a diaphragm, 23 is a voice coil, and 24 is a voice coil lead. , 26 is a top plate, 26 is a magnet, 27 is a plate with a center pole, 28 is a frame, 29 is a shield plate/terminal, and 30 is a back cover. Top plate 26
゜Magnet 26. The plates 27 with center poles are combined to form a magnetic circuit 32 having a concentric magnetic gap 31, and the magnetic circuit 32 is connected to the inside of a frame 28 made of an insulating material such as resin to form a housing assembly. Also,
A voice coil 23 is mounted on a diaphragm 22 made of resin film.
are glued together to form a vibration system, and the peripheral part of the imaging plate 22 of this vibration system is attached to the guide 33 of the frame 28 of the housing assembly.
Glue it to the inner circumference of the A shield plate/terminal 29 made of high permeability material such as iron has ventilation holes on the front side of the imaging plate 22.
The baffle plate 21 is molded into an insulating material such as resin.
are arranged and adhered to the frame 28, and a back cover 30 is adhered to the frame 28 to constitute an electroacoustic transducer.

In the above configuration, the baffle plate 21 molded from a high magnetic permeability material is connected to the diaphragm outer circumferential guide 3 of the frame 28.
The front surface of the diaphragm 22 is provided with a guide 34 that fits into the frame 28, and by gluing the fitting part and filling the guide part 34 of the frame 28, which is missing for drawing out the voice coil lead 24, with adhesive or the like. The acoustic space is separated from the conductive parts such as the shield plate/terminal 29. Further, the shield plate/terminal 29 made of a high-magnetic material such as iron and molded on the baffle plate 21 has a vertical portion reaching the center ball plate 27 on the outer periphery of the diaphragm guide portion 33 of the frame 28, and has a magnetic air gap. A magnetic circuit 32 is configured to direct leakage magnetic flux toward the front surface of the center ball plate 27 toward the center ball plate 27. With this configuration, when a charged object approaches the front surface of the unit, the discharge path follows the outer wall of the unit, making it difficult to cause dielectric breakdown.

Further, even if dielectric breakdown occurs, spark discharge is difficult to occur, and the discharge occurs when high resistance elements are connected in series.

In addition, leakage magnetic flux from the magnetic gap 31 is also absorbed by the baffle plate 21.
Since the magnetic flux passes through the magnetic circuit 32 to the plate 27 with the center pole through the shield plate/terminal 29 made of a high magnetic permeability material such as molded iron, the leakage magnetic flux to the front of the unit is reduced.

Effects of the Invention As described above, the present invention comprises a magnetic circuit that directs leakage magnetic flux toward the front surface of the magnetic gap toward the plate with a center pole using a high magnetic permeability material, and the high magnetic permeability material located at the front surface of the diaphragm is made of resin. Wrap it in an insulating material and use it as a baffle plate.
Furthermore, by separating the acoustic space in front of the diaphragm, the magnetic circuit, and the conductive part from the joint between the powerful board and the frame, or by increasing the distance, sparks from the charged human body can be directed to the terminal part. It is possible to provide a safe and comfortable electroacoustic transducer that does not cause discharge and does not attract tabletop pins due to leakage magnetic flux, and is of great industrial value.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a sectional view showing the structure of an embodiment of the electroacoustic transducer of the present invention, and FIGS. 2 and 3 are sectional views showing the structure of a conventional electroacoustic transducer. be. 21... Baffle plate, 22... Vibration plate,
23... Whis coil, 28... Frame, 29... Shield plate and terminal, 3o...
... Back cover, 31 ... Magnetic gap, 3
2...Magnetic circuit. Name of agent: Patent attorney Toshio Nakao and one other person? !
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Claims (1)

[Claims] A magnetic circuit with a magnetic air gap is housed within the frame, and a diaphragm with a voice coil that fits into the magnetic air gap of this magnetic circuit is incorporated, and a shield plate and terminal made of a high magnetic permeability material is molded on the front of this diaphragm. An electroacoustic transducer comprising a molded baffle plate arranged so that a part of the shield plate/terminal is located near the outer periphery of the magnetic circuit.