WO2010044128A1

WO2010044128A1 - Electromagnetic converter

Info

Publication number: WO2010044128A1
Application number: PCT/JP2008/002955
Authority: WO
Inventors: 吉田俊治
Original assignee: 三菱電機エンジニアリング株式会社
Priority date: 2008-10-17
Filing date: 2008-10-17
Publication date: 2010-04-22
Also published as: KR101058287B1; JPWO2010044128A1; TWI424753B; KR20110009715A; CN102067628A; TW201018264A; JP4553983B2

Abstract

An electromagnetic converter (10) is composed of an upper frame (16) and a lower frame (17) whereupon sound discharge holes (15a) are arranged, a vibrating membrane (11) whereupon a conductor coil (11b) of a meandering coil pattern attached to the lower frame (17) is formed; and permanent magnets (12, 13) alternately fixed in staggered arrangement on the facing inner wall surfaces of the upper frame (16) and the lower frame (17) by sandwiching the vibrating membrane (11). After assembling the electromagnetic converter (10), end surfaces of the permanent magnets (12, 13) facing each other are alternately magnetized to different polarities by magnetizing the end surfaces in a direction vertical to the upper frame (16) and the lower frame (17).

Description

Electromagnetic transducer

The present invention relates to an electromagnetic transducer for reproducing sound from an audio signal by combining a permanent magnet and a diaphragm.

Some conventional electromagnetic transducers that combine a permanent magnet plate and a diaphragm are arranged so that the permanent magnet plate and the diaphragm are opposed to each other, and a buffer material is arranged between the permanent magnet plate and the diaphragm. . These permanent magnet plates, vibration films, and cushioning materials are covered so as to be sandwiched between members such as a frame, and are attached to, for example, a speaker housing.

The permanent magnet plate has strip-shaped magnet portions (also referred to as a multipolar magnetized pattern) alternately having different polarities at regular intervals. Further, the vibrating membrane is formed by forming a meandering coil pattern in a so-called magnetized neutral zone at a position opposite to the interval at the boundary of different polarities of the permanent magnet plate. When an audio signal current flows through the serpentine coil pattern formed on the diaphragm, the serpentine coil pattern and the multi-pole magnetized pattern of the permanent magnet are electromagnetically coupled, and current is applied to the serpentine coil pattern by Fleming's law. The vibrating membrane vibrates by acting. The sound wave generated by this vibration is radiated to the outside through a radiating sound hole drilled in the permanent magnet plate and the frame, and audio reproduction is performed (see, for example, Patent Document 1).
In addition, the vibration film is reinforced with a rigidity imparting member for the purpose of preventing the conductor coil of the meandering coil pattern formed on the vibration film from being broken due to metal fatigue due to this vibration (see, for example, Patent Document 2). .

Conventionally, there is a thin speaker called “gummazon type” having a configuration similar to that of the above-described electromagnetic transducer and configured by a long bar-shaped magnet instead of the permanent magnet plate. A thin-type speaker of the Gamson type sandwiches the front and back of the diaphragm with a bar-shaped magnet plate in which bar magnets of different polarities are arranged alternately, and the poles of the bar-shaped magnets facing each other across the diaphragm are the same (N pole and N pole, or The other members are composed of the same members as those of the electromagnetic transducer described above.
Such a thin speaker has a vibration film formed by attaching copper or aluminum foil to a thin film made of polyester or polyimide and etching a voice coil pattern (see, for example, Non-Patent Document 1). The thin speaker having this configuration also has the same sound wave generation operation for audio reproduction as the electromagnetic transducer.

Japanese Patent No. 3192372 International Publication WO2003 / 073787

Since the conventional electromagnetic transducer is configured as described above, after magnetizing the permanent magnet, it must be attached to the frame while paying attention to the direction of each magnetic pole, and there is a problem that work efficiency is poor. there were.
Further, the work must be performed in a magnetized and magnetized state, and foreign matters such as iron powder are easily mixed during the work process. For this reason, the electromagnetic transducer has a problem that abnormal noise is generated due to foreign matter mixing, and the initial performance is not achieved.

The present invention has been made to solve the above-described problems. An electromagnetic conversion in which all permanent magnets can be magnetized in a lump after attaching a non-magnetized permanent magnet to a frame and assembling the electromagnetic transducer. The purpose is to provide a vessel.

The electromagnetic transducer according to the present invention opposes a hollow frame having a sound emitting hole on the surface thereof, and a vibrating membrane having a serpentine coil pattern formed on the surface and disposed inside the frame, with the vibrating membrane interposed therebetween. The frame includes a plurality of permanent magnets alternately fixed to a pair of inner wall surfaces of the frame in a staggered arrangement and opposite to the fixed surfaces and having oppositely opposite end surfaces.

According to the present invention, a plurality of permanent magnets are alternately fixed to the pair of inner wall surfaces of the frame in a staggered arrangement, and opposite end surfaces opposite to each other and having opposite polarities. Thus, after permanent magnets that are not magnetized are attached to the frame and the electromagnetic transducer is assembled, all the permanent magnets can be magnetized together. As a result, the steps for magnetization can be reduced, and the efficiency of assembly work can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is an external view which shows the structure of the electromagnetic transducer based on Embodiment 1 of this invention, FIG.1 (a) is an external appearance front view, FIG.1 (b) is an external appearance side view, FIG.1 (c) is an external appearance top view. FIG. 1D is an external rear view. FIG. 2 is a cross-sectional view showing the structure of the electromagnetic transducer according to Embodiment 1 of the present invention. FIG. 2 (a) is a cross-sectional view taken along line AA shown in FIG. 1 (a), and FIG. ) Is a cross-sectional view taken along the line BB, and FIG. 2C is a cross-sectional view taken along the line CC. It is a perspective view which shows the external appearance of the diaphragm of the electromagnetic transducer which concerns on Embodiment 1 of this invention. FIG. 4A is a cross-sectional view showing the structure of an electromagnetic transducer according to Embodiment 2 of the present invention, and FIG. 4A is a cross-sectional view cut at a position corresponding to the line AA shown in FIG. (B) is a cross-sectional view cut at a position corresponding to line BB.

Hereinafter, in order to describe the present invention in more detail, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.
Embodiment 1 FIG.
1A and 1B are external views showing the structure of an electromagnetic transducer 10 according to Embodiment 1 of the present invention. FIG. 1A is an external front view, FIG. 1B is an external side view, and FIG. ) Is an external plan view, and FIG. 1D is an external rear view. 1 (a) and 1 (b), a structure that is accommodated in the frame 15 and is not actually visible is indicated by a dotted line.
2 is a cross-sectional view showing the structure of the electromagnetic transducer 10 according to Embodiment 1 of the present invention, and FIG. 2 (a) is a cross-sectional view taken along the line AA shown in FIG. 1 (a). 2B is a cross-sectional view taken along the line BB shown in FIG. 1A, and FIG. 2C is a cross-sectional view taken along the line CC shown in FIG. 1A. It is. FIG. 3 is a perspective view showing the appearance of the vibration film 11 of the electromagnetic transducer 10 according to Embodiment 1 of the present invention.
FIGS. 1 to 3 are exaggerated and enlarged for the sake of simplicity, and are different from the actual scale.

The electromagnetic transducer 10 includes an upper frame 16, a permanent magnet 12, a vibration film 11, a permanent magnet 13, and a lower frame 17. A frame 15 is constituted by the upper frame 16 and the lower frame 17, and the frame 15 has a hollow casing structure. Here, for convenience, they are referred to as an upper frame and a lower frame, but they may be turned upside down.
On the inner wall surface of the upper frame 16, that is, the surface facing the vibration film 11, permanent magnets 12 are fixed with an adhesive at predetermined intervals. A plurality of rows of permanent magnets 13 are fixed with an adhesive at a position corresponding to a gap between the permanent magnets 12 on the inner wall surface of the lower frame 17, that is, the surface facing the vibration film 11. Therefore, as shown in the cross-sectional view of FIG. 2A, the

permanent magnets

12 and 13 are arranged in a staggered manner in which the

permanent magnets

12 and 13 are alternately fixed to the upper frame 16 and the lower frame 17.

2A, in the permanent magnet 12 fixed to the upper frame 16, the end surface fixed to the upper frame 16 has an N pole, and the end surface facing the vibration film 11 has an S pole. On the other hand, in the permanent magnet 13 fixed to the lower frame 17, the end surface fixed to the lower frame 17 is the S pole and the end surface facing the vibration film 11 is the N pole. Therefore, the

permanent magnets

12 and 13 have a configuration in which end faces facing each other on the side opposite to the fixed face have different polarities.

Further, sound emitting holes 15a that are open to the outside are provided at regular intervals in portions of the upper frame 16 and the lower frame 17 where the

permanent magnets

12 and 13 are not fixed.

The vibration film 11 is made of a thin polymer sheet substrate 11a. This base material 11a is three-dimensionally structured into a concavo-convex shape having a width that matches the fixed interval between the

permanent magnets

12 and 13. The concave / convex shape is a shape along the concave / convex structure formed by the end faces of the

permanent magnets

12 and 13 facing each other.
On the surface of the vibration film 11, a conductor coil 11b is formed in a meandering shape. The conductor coil 11b is formed by punching a foil of an electric conductor of copper or aluminum by etching or pressing.
A diaphragm support member 14 is fixed to the outer periphery of the diaphragm 11. By fixing the diaphragm support member 14 to the inner periphery of the lower frame 17, the diaphragm 11 is supported so as to be vertically displaced. As shown in FIG. 2 (a), the diaphragm support member 14 fixes the diaphragm 11 to the lower frame 17. At this time, the conductor coil 11b has a height at which the end faces of the

permanent magnets

12 and 13 face each other. It is aligned to be in position.

A space is provided between the vibration film 11 and the

permanent magnets

12 and 13 so that the vibration film 11 supported by the vibration film support member 14 does not come into contact with the

permanent magnets

12 and 13 when the vibration film 11 is displaced up and down. Thus, the uneven shape of the substrate 11a is formed.
Moreover, in order to improve the rigidity of the vibration film 11, the vibration film reinforcement structure part 11c of a rib structure or an uneven structure is provided in the convex surface of the vibration film 11 front and back.

Next, a method for magnetizing the

permanent magnets

12 and 13 will be described.
First, the permanent magnets 12 are fixed to the upper frame 16 and the permanent magnets 13 are fixed to the lower frame 17 in a staggered arrangement, and the electromagnetic transducer 10 is assembled with the vibration film 11 interposed therebetween. Thereafter, the assembled electromagnetic transducer 10 is uniformly magnetized in a direction perpendicular to the upper frame 16 and the lower frame 17 so that the

permanent magnets

12 and 13 are magnetized in the same magnetic pole direction. Therefore, the mutually opposing end portions of the

permanent magnets

12 and 13 have alternately different belt-like polarities.

Next, the operation principle of the electromagnetic transducer 10 will be described.
In the electromagnetic transducer 10 shown in FIGS. 1 and 2, when a current (audio signal) is supplied from the outside to the conductor coil 11b of the diaphragm 11, the magnetic flux emitted from the N pole of the permanent magnet 13 is orthogonal to the conductor coil 11b. To the south pole of the permanent magnet 12. At this time, the current flowing in the meandering coil pattern of the conductor coil 11b formed substantially perpendicular to the magnetic flux direction of the

permanent magnets

12 and 13 and the magnetization pattern (magnetic flux density) of the

permanent magnets

12 and 13 are electromagnetically coupled. A driving force is generated according to Fleming's law. Due to the generated driving force, the vibration film 11 supported by the vibration film support member 14 vibrates. This vibration is radiated as an audio reproduction sound from a sound emission hole 15 a provided in the frame 15.

According to the first embodiment described above, the vibration film 11 is made uneven, and the

permanent magnets

12 and 13 are arranged in a staggered arrangement so that the magnetic pole direction of the permanent magnet 12 and the magnetic pole direction of the permanent magnet 13 are the same. Since it comprised, the

permanent magnets

12 and 13 can be magnetized collectively after the assembly of the electromagnetic transducer 10. For this reason, it is possible to reduce the work of attaching to the frame while paying attention to the direction of each magnetic pole after magnetizing the permanent magnet, as in the conventional Gamson-type speaker, and to improve the assembly work efficiency.
Moreover, since it magnetizes after the assembly of the electromagnetic transducer 10, foreign matter such as iron powder is not mixed during the assembly operation. Therefore, it is possible to prevent abnormal noise from being generated in the electromagnetic transducer 10 and prevent the original performance from being produced, and to easily manufacture the electromagnetic transducer 10 with high quality.

The conductor coil 11b may be formed on one side of the base material 11a, or may be formed on both the front and back surfaces of the base material 11a as shown in FIG. When it is formed on both the front and back surfaces, the audio signal can be converted into audio reproduction sound more faithfully.
In the first embodiment, the

permanent magnets

12 and 13 fixed to the frame 15 are collectively magnetized after the electromagnetic transducer 10 is assembled. However, the magnets are divided into the upper frame 16 and the lower frame 17. The structure which magnetizes the

permanent magnets

12 and 13 separately may be sufficient.
In the first embodiment, the

permanent magnets

12 and 13 are arranged in three rows, but the same effect as in the first embodiment can be obtained if the configuration includes two or more rows.

Embodiment 2. FIG.
FIG. 4 is a cross-sectional view showing the structure of an electromagnetic transducer 10 according to Embodiment 2 of the present invention. FIG. 4 (a) shows the electromagnetic transducer 10 along the line AA shown in FIG. 1 (a). FIG. 4B is a cross-sectional view of the electromagnetic transducer 10 cut at a position corresponding to the line BB shown in FIG. 1A. In FIG. 4, the same or corresponding parts as those of the electromagnetic transducer 10 described in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

In the electromagnetic transducer 10 shown in FIG. 4, an iron plate 18 for increasing the magnetic flux density is bonded and fixed to the end faces of the

permanent magnets

12 and 13 facing the vibrating membrane 11.
In the electromagnetic transducer 10, since the iron plate 18 and the conductor coil 11b are at the same height position, the magnetic flux concentrated on the iron plate 18 is electromagnetically coupled with the current flowing through the conductor coil 11b to obtain a larger sound pressure level. It is done.

According to the above-described second embodiment, the iron plate 18 is bonded and fixed to the end faces of the

permanent magnets

12 and 13 facing the vibration film 11. Therefore, the magnetic flux density passing through the conductor coil 11b can be increased.

As described above, the electromagnetic transducer according to the present invention is suitable for use in a speaker because it is magnetized after assembly to prevent foreign matter from entering and prevent abnormal noise from being generated.

Claims

A hollow frame with sound emission holes on the surface;
A serpentine coil pattern is formed on the surface, and a vibrating membrane installed inside the frame;
A plurality of permanent magnets alternately fixed to a pair of inner wall surfaces of the frame opposed to each other with the vibration film sandwiched therebetween, and having opposite polarities on opposite sides opposite to the fixed surfaces. Electromagnetic transducer with
The vibration film is formed in a concavo-convex shape corresponding to the concavo-convex structure constituted by end faces of the permanent magnets arranged in a staggered manner, and the meandering coil pattern is formed at a position substantially orthogonal to the magnetic flux direction of the permanent magnet. The electromagnetic transducer according to claim 1.
3. The electromagnetic transducer according to claim 2, wherein a reinforcing rib structure or an uneven structure is formed on the vibrating membrane.
2. The electromagnetic transducer according to claim 1, wherein iron plates are fixed to end faces of the permanent magnets arranged in a staggered manner.
A hollow frame with sound emission holes on the surface;
A serpentine coil pattern is formed on the surface, and a vibrating membrane installed inside the frame;
A direction perpendicular to the pair of inner wall surfaces after assembling an electromagnetic transducer comprising a plurality of permanent magnets fixed in a staggered arrangement on a pair of inner wall surfaces of the frame opposed to each other with the vibration film interposed therebetween Electromagnetic transducers in which end faces facing each other of the permanent magnets arranged in a staggered manner have different polarities by being magnetized in a different manner.