WO2009144773A1

WO2009144773A1 - Electromagnetic convertor

Info

Publication number: WO2009144773A1
Application number: PCT/JP2008/003198
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: 2008-05-28
Filing date: 2008-11-05
Publication date: 2009-12-03
Also published as: JP4823272B2; JP2011171781A

Abstract

An electromagnetic convertor comprises eternal magnets arranged with a predetermined gap therebetween and with their polarities alternately different from each other, a vibrating membrane which is arranged opposite to the eternal magnet and on which a meandering coil pattern is formed, and a frame in which a sound output hole for radiating the vibration of the vibrating membrane to the outside is provided. In the electromagnetic convertor, a magnetic holding portion which is fit into the frame and which fixes and supports the eternal magnet is provided, both ends of the band-like eternal magnet are fit into the magnet holding portion, and thus the eternal magnet is fixed and supported.

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 vibration membrane.

Conventionally, an electromagnetic transducer combining a permanent magnet plate and a diaphragm is 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. There is. The permanent magnet plate, the vibration film, and the buffer member 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 magnetized portions (also referred to as multipolar magnetized patterns) alternately having different polarities at regular intervals. In addition, the vibration film is opposed to a position at a boundary of different polarities of the permanent magnet plate, that is, a so-called magnetized neutral zone, and a meandering conductor pattern (meandering coil) acting as an electromagnetic coil. (Also referred to as a pattern) is provided on the surface of the vibration film.
When an audio signal current flows through the serpentine coil pattern formed on the diaphragm, the serpentine coil pattern and the multipolar magnetization pattern of the permanent magnet plate are electromagnetically coupled, and the above-described serpentine coil pattern is formed by Fleming's law. Acts and the vibrating membrane vibrates. The sound wave generated by this vibration is radiated through a sound hole formed in the permanent magnet plate and the frame, and audio reproduction is performed (for example, see Patent Document 1).
In addition, for the purpose of preventing the conductor coil formed on the vibration film from being broken by metal fatigue due to such vibration, a rigidity imparting member is provided on the vibration film (see, for example, Patent Document 2).
Conventionally, there is an ultra-thin speaker called “Gum-Zone” that has a configuration similar to that of the above-described electromagnetic transducer and has a long bar-shaped magnet instead of the permanent magnet plate. This bar magnet has the same polarity (N pole and N pole, or S pole and S pole), and has different polarities arranged in the arrangement direction perpendicular to the bar magnet. It consists of the same thing as the above. Such an ultra-thin speaker has a diaphragm 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). ). According to this configuration, the sound generation operation for audio reproduction is the same as that of the electromagnetic transducer.

Japanese Patent No. 3192372 International Publication WO2003 / 073787

However, any of the conventional electromagnetic transducers is an electromagnetic transducer in which different magnetic poles of a permanent magnet are attached to a frame of an iron casing structure with an adhesive or the like at a predetermined interval.
However, in the conventional electromagnetic transducer, the sintered magnets must be bonded one by one to the frame of the iron casing structure, and accuracy is required for the arrangement of the permanent magnets. There is a problem that work efficiency is poor because a dedicated jig or the like must be used for positioning. Further, in the case of a rod-shaped permanent magnet, there is a problem that the number of the magnets is large and the work process becomes complicated and takes time, resulting in high cost.

The present invention has been made to solve the above-described problems, and it is an object of the present invention to provide an electromagnetic transducer that can be fixed to a frame in a short time without using an adhesive and preventing a permanent magnet from moving. It is said.

The electromagnetic transducer according to the present invention includes a permanent magnet that is alternately arranged with different band-like polarities at a predetermined interval, a vibration film that is disposed to face the permanent magnet and has a meandering coil pattern, and a vibration In an electromagnetic transducer comprising a frame provided with sound emission holes for radiating membrane vibrations to the outside, and a magnet holder fitted to the frame and fixedly supporting the permanent magnet, both ends of the belt-like permanent magnet are magnets. The permanent magnet is fixedly supported by being fitted into the holding portion.

According to the electromagnetic transducer of the present invention, since the magnet holding means for holding the thickness direction of the electromagnetic converter is provided as the permanent magnet holding means, the accuracy of the arrangement of the permanent magnets can be improved and the number of processes can be reduced. Workability can be improved.

It is the perspective view which shows (a) external appearance of the electromagnetic transducer 10 of this invention, and (b) is an exploded perspective view which shows a structure. 2A is a cross-sectional view taken along line AA, FIG. 2B is a cross-sectional view taken along line BB, and FIG. 3C is a cross-sectional view taken along line CC. 4A is a sectional view taken along line AA, FIG. 5B is a sectional view taken along line BB, and FIG. 5C is a sectional view taken along line CC.

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.
FIG. 1 is a diagram illustrating a configuration of an electromagnetic transducer 10 according to the present invention. FIG. 1A is an overall perspective view illustrating an external appearance of the electromagnetic transducer 10, and FIG. 1B is a configuration of the electromagnetic transducer 10. It is a disassembled perspective view shown.
2A and 2B are diagrams illustrating the structure of the electromagnetic transducer 10 according to the first embodiment. FIG. 2A is a cross-sectional view taken along the line AA in FIG. 1A, and FIG. FIG. 2A is a sectional view taken along the line BB of FIG. 1A, and FIG. 2C is a sectional view taken along the line CC of FIG. In order to simplify the description, some of the actual dimensions may be different.

The electromagnetic transducer 10 includes a vibration film 11, spacers (magnet holding means) 21 and 22,

permanent magnets

31 and 32, and a frame 40, and the vibration film 11 is composed of an upper frame 41 and a lower frame 42 of the frame 40. And the

permanent magnets

31 and 32 are covered.

The vibration film 11 includes a base material 11a made of a thin polymer resin sheet, and a conductor coil (coil) 11b formed in a meandering shape on the surface of the base material 11a. It is formed by punching a metal foil by pressing or etching.

The

spacers

21 and 22 are made of, for example, an elastic resin material such as POM (polyacetal), and support the both ends of the vibration film 11 so as to sandwich the

permanent magnets

31 and 32 with the same width. A fitting portion 21a having a partition is provided so that the longitudinal end portions of the 32 can be fitted at a predetermined interval.

The long

permanent magnets

31 and 32 are formed by mixing (injection molding, etc.) a magnetic powder (neodymium powder, ferrite powder, samarium-cobalt powder, etc.) and a binder (plastic material, rubber material, etc.). Molded and magnetized with an easy bond magnet. The magnetized strip-shaped

permanent magnets

31 and 32 are arranged so that the surfaces facing the vibration film 11 are alternately different magnetic poles (hereinafter also referred to as a multipolar magnetization pattern), and the vibration film of the frame 40 11 is fixed to the surface facing 11 with an adhesive or the like at a predetermined interval.

The frame 40 has a housing structure having a hollow interior in which an upper frame 41 made of a metal such as iron and a lower frame 42 are overlapped, and a joint surface between the upper frame 41 and the lower frame 42 is a vibration film. A part of both ends of 11 is sandwiched and supported.

Sound emitting holes

41a and 42a that are open to the outside are provided at regular intervals at positions facing the conductor coil 11b of the vibration film 11, and protrusions that are half-pierced by pressure processing such as indenting.

Portions

41b and 42b are provided. The band-shaped

permanent magnets

31 and 32 are positioned at the position in the surface direction (horizontal direction) of the electromagnetic transducer 10 by the

projections

41b and 42b subjected to the half-piercing process.

Here, the conductor coil 11b of the vibrating membrane 11 and the

permanent magnets

31 and 32 are arranged at positions facing the predetermined interval between the

permanent magnets

31 and 32 fixed to the frame 40. It is formed as follows.
In addition,

protrusions

41b and 42b that are half-pierced together with

sound emitting holes

41a and 42a are provided at the position of the frame 40 facing the conductor coil 11b of the vibration film 11. The frame 40 has permanent magnets 31,

Protrusions

41b and 42b are also provided at both end portions where 32 is disposed.
The

spacers

21 and 22 are sandwiched and supported by the inner wall of the frame 40 due to their elasticity.
The electromagnetic transducer 10 according to Embodiment 1 of the present invention is configured as described above.

Next, a method for fixing the

permanent magnets

31 and 32 of the electromagnetic transducer 10 to the frame 40 will be described.
When the permanent magnet 31 is disposed between the protrusions 41b of the upper frame 41 so that the surfaces facing the vibration film 11 are alternately different magnetic poles, the permanent magnet 31 sandwiched between the protrusions 41b is in the surface direction of the frame 41. And is brought into close contact with the upper frame 41 by the magnetic force thereof. Further, the spacer 21 is fitted between the both ends of the belt-like shape of the permanent magnet 31 and the inner wall of the frame 41 so that the spacer 21 and the frame 41 are fitted together. 10 is supported in the thickness direction.
Further, the permanent magnet 32 is also supported in the thickness direction of the electromagnetic transducer 10 by the spacer 22 and the frame 42 in the same manner as the permanent magnet 31.
In this way, the

permanent magnets

31 and 32 can be fixed to the

frames

41 and 42, and the

frames

41 and 42 to which the

permanent magnets

31 and 32 are fixed are overlapped and engaged by an engagement portion (not shown), The electromagnetic transducer 10 is manufactured.

Next, the operation of the electromagnetic transducer 10 will be described.
In the electromagnetic transducer 10 having the above configuration, when a current (audio signal) is supplied to the conductor coil 11b of the vibration film 11 via the

spacers

21 and 22, multipolar attachment of the conductor coil 11b and the

permanent magnets

31 and 32 is performed. The magnetic pattern is electromagnetically coupled, and the vibration film 11 is displaced according to Fleming's law to generate vibration. This vibration causes the air in the frame 40 to vibrate and is radiated as audio vibration from the sound emission holes 41 a and 42 a of the frame 40.

As described above, in the electromagnetic transducer 10 according to the first embodiment, the

protrusions

41 b and 42 b provided on the frame 40 position the frame 40 in the surface direction, and the

spacers

21 and 22 connect the

permanent magnets

31 and 32 to the frame 40. Since it is possible to fix a permanent magnet such as a long-sized bond magnet to the frame 40 without using an adhesive, it is possible to make a simple configuration in consideration of the environment. Manufacturing processes can be reduced and productivity can be improved.
Further, since the

permanent magnets

31 and 32 are accurately positioned and fixed by the

frames

41 and 42 and the

spacers

21 and 22, the long-life electromagnetic transducer 10 can be easily manufactured without the

permanent magnets

31 and 32 falling off. can do.

In the first embodiment, it is described that the conductor coil 11b having a meandering pattern is formed on the surface of the vibration film 11. However, in order to more accurately convert an electric signal into audio vibration, the vibration film The conductor coil 11 b may be formed on both sides of the electrode 11.
In the first embodiment, the magnetized band-like

permanent magnets

31 and 32 are used. However, the magnets may be magnetized after being fixed to the frame 40, and different magnetic poles may be formed at a predetermined interval. Permanent magnet plates magnetized alternately may be used.
In the method for fixing the

permanent magnets

31 and 32 of the electromagnetic transducer 10 according to the first embodiment, the

spacers

21 and 22 are fitted to the frame 40 after the

permanent magnets

31 and 32 are fitted between the

protrusions

41b and 42b. However, the longitudinal ends of the

permanent magnets

31 and 32 may be fitted into the

spacers

21 and 22 first.

Embodiment 2. FIG.
In the electromagnetic transducer 10 of the first embodiment, the

protrusions

41b and 42b provided on the frame 40 by half piercing process are positioned in the surface direction of the frame 40. However, as shown in FIG. Protrusions 51 and 52 made of a non-magnetic material using the same resin as that of 22 may be provided.

3 is a cross-sectional view showing the configuration of the electromagnetic transducer according to the second embodiment. FIG. 3A is a cross-sectional view taken along the line AA of the electromagnetic transducer 10 in FIG. 1, and FIG. FIG. 3C is a cross-sectional view of the electromagnetic transducer 10 of FIG. 1, and FIG. 3C is a cross-sectional view of the electromagnetic transducer 10 of FIG. In addition, since structures other than the

protrusion parts

51 and 52 are the same as that of Embodiment 1, it shows with the same number and abbreviate | omits description.

The

protrusions

51 and 52 are formed in a rectangular column shape with a resin material having elasticity in the hole where a hole is made in the same place as the half piercing process in the electromagnetic transducer 10 of the first embodiment. 52 is fitted and protruded to the inner surface of the frame structure of the frame 40.

The arrangement of the frame 40 in the surface direction can be positioned by sandwiching the band-like

permanent magnets

31 and 32 between the

protrusions

51 and 52.

In the second embodiment, the

protrusions

51 and 52 are only fitted into the holes provided in the frame 40, but the

protrusions

51 and 52 made of a resin material are fixed to the frame by performing outsert molding. You may form as follows.

As described above, according to the electromagnetic transducer 10 of the second embodiment, the

projections

51 and 52 made of a resin material for positioning the electromagnetic transducer 10 in the surface direction are provided on the frame 40, and the thickness of the electromagnetic transducer 10 is increased. Since the

spacers

21 and 22 for supporting the direction are provided, the same effect as in the first embodiment can be obtained.

In the electromagnetic transducer 10 according to the first and second embodiments of the present invention, the

projections

41b, 42b, 51, 52 are provided on the frame 40 to perform positioning in the surface direction. Not only 42b, 51, 52 but a groove that can be positioned in the surface direction of the

permanent magnets

31, 32 may be provided.
Moreover, although it has shown that the

permanent magnets

31 and 32 of this invention are comprised with the strip | belt-shaped magnet long in a frame longitudinal direction, it is the structure which vibrates the vibration film 11 with the conductor coil 11b and the

permanent magnets

31 and 32. If it exists, you may comprise with a strip | belt-shaped permanent magnet long in a frame transversal direction.
In addition, it has been described that the

spacers

21 and 22 in the electromagnetic transducer 10 of the present invention are sandwiched and supported by the inner wall of the frame 40. However, the

spacers

21 and 22 and the frame 40 are fitted and fixed, so that the

spacer

21 , 22 are provided with an engaging claw portion (not shown) on the outer periphery of the frame 22 and an engagement receiving portion (not shown) on the upper and

lower frames

41, 42 of the frame 40, and both are engaged and fixed when fitted. It may be configured as follows.
Further, the drawings shown in the embodiments of the present invention are exaggerated and enlarged for easy understanding, and the relationship of the thicknesses of the respective components may be different from the actual ones.

As described above, the electromagnetic transducer according to the present invention includes the magnet holding means for holding the thickness direction of the electromagnetic converter as the permanent magnet holding means, thereby improving the accuracy of the arrangement of the permanent magnets. As the assembly workability is improved, it is suitable for use in a built-in speaker of a thin monitor.

Claims

Permanent magnets arranged in different strip-like polarities alternately at predetermined intervals;
A vibrating membrane disposed opposite the permanent magnet and having a serpentine coil pattern formed thereon,
In an electromagnetic transducer comprising a frame provided with a sound emitting hole for radiating vibrations of the vibrating membrane to the outside,
A magnet holding part fitted to the frame and fixedly supporting the permanent magnet;
An electromagnetic transducer, wherein both ends of the belt-like permanent magnet are fitted into the magnet holding portion, and the permanent magnet is fixedly supported.
The frame includes a plurality of protrusions formed on a surface facing the vibration film,
2. The electromagnetic transducer according to claim 1, wherein a band-shaped permanent magnet is fitted between the plurality of protrusions to perform positioning in the surface direction.
3. The electromagnetic transducer according to claim 2, wherein the protrusion is made of a pressed half piercing provided adjacent to the sound emitting hole.
3. The electromagnetic transducer according to claim 2, wherein the protrusion is formed of a non-magnetic material in a hole provided adjacent to the sound emitting hole.
5. The electromagnetic transducer according to claim 4, wherein the protrusion is a resin material that is outsert molded.