JPH01258589A - Motor driven electroacoustic transducer - Google Patents

Abstract

PURPOSE:To eliminate a damage due to the cutting of a lead wire or the disconnection of soldering by moving a field magnet without moving a voice coil and pulling the lead wire by the voice coil and oscillating it. CONSTITUTION:A dynamic cone speaker 16 has the stator 20 of a field part constituted by integrally forming a center pole 17, a yoke plate 18 and a frame 19. To the upper end peripheral edge part of the frame 19, a conical oscillator 21 is connected. To the central part of the lower part of this oscillator 21, the cylindrical field magnet 22 is connected and can be axially reciprocated in a magnet gap 30. In the internal peripheral face 18b of the yoke plate 18, the cylindrical stator voice coil 23 is fixed and the lead wire 25 thereof is pulled out of a through hole 26 disposed at the lower part of the yoke plate 18.

Description

[Detailed Description of the Invention] [Industrial Application Field of the Invention] The present invention relates to an electrodynamic electroacoustic exchanger for speakers, microphones, earphones, telephones, etc., and its feature is that the voice coil is fixed. The structure is such that the field magnet moves, reducing the weight of the movable body.As a result, the response speed is improved and the efficiency of converting vibration into sound or current is increased, making it easy to produce low-pitched sounds. It is expected to have a long service life as it eliminates the need to drag lead wires, and the structure is simplified so that it can be mass-produced at low cost. The reason is that it is an efficient electroacoustic exchanger.

[Technical Background and Problems] Electrodynamic electroacoustic exchanger 9 For example, in a speaker, when the voice coil is movably placed in a magnetic field and a sound current is passed through it, the voice coil vibrates as the current changes. This is what I did. In this case, a speaker that reproduces sound waves by moving a vibrating body with a coil is called a dynamic speaker, and a speaker that emits sound waves by directly connecting a coil to a cone-shaped paper or the like is called a dynamic cone speaker. A dynamic horn speaker is a speaker that uses a voice coil to move a small vibrating body and attaches a horn (or trumpet) to the front of the vibrating body to efficiently radiate sound waves. A microphone, for example, a dynamic microphone, has a similar structure to a dynamic speaker.

Conversely, when the vibrating body moves in response to sound waves, the voice coil attached to it vibrates within the magnetic field and generates an electric current. Since these electrodynamic electroacoustic exchangers all have similar structures, the speaker will be explained below.

Many conventional dynamic cone speakers 1 are constructed as shown in FIG.

That is, a permanent magnet 4 made of a cylindrical ferrite magnet is placed on a yoke plate 3 equipped with a center ball (center magnetic pole) 2, and an upper yoke plate 5, which is also cylindrical, is fixed with adhesive or the like to create a field. The field section 6 constitutes the fixed side.The field section 6 shown here is called an external magnet type, and uses a yoke, and a columnar permanent magnet and a center magnet are installed in the center of the yoke. It may also be of the so-called internal magnetic type that incorporates a ball.

A cone-shaped frame 7 is coupled to this field section 6.
The peripheral edge of a cone-shaped vibrating body 9 is bonded to the peripheral edge of the frame 7 together with a gasket (satellite) 8 using an adhesive or the like. A coil bobbin 11 made of paper, thin plastic, or the like and having a cylindrical voice coil 10 wound therein is coupled to the center of the vibrating body 9.

The middle part of the coil bobbin 11 holds the voice coil 10 at the center between the magnetic poles and performs appropriate damping (braking) on vibrations.
The voice coil 10 is supported by a damper 12 for applying pressure, so that the voice coil 10 is correctly positioned within the magnetic gap 13 of the field section 6. Further, a dust cap 14 such as a dustproof cloth is attached to the upper surface of the central portion of the vibrating body 9 to prevent dust in the air from entering the annular magnetic gap 13.

According to such a conventional speaker 1, the voice coil 1
0 drags the lead wire and vibrates, so if used for a long time, the lead wire may break or the solder may come off, leading to damage and shortening the service life. there were.

Further, as shown in FIG. 7, the lead wire 15 of the voice coil 10 is pulled out from the upper part through the magnetic gap 13, guided to the vibrating body 9 (or the frame 7), and placed at that position. Because it is soldered to ■
In order to pass both terminals of the lead wire 5 of the voice coil 10 into the magnetic gap 13, the voice coil 1o has a limited thickness.
By using this method, the magnetic flux density within the magnetic gap 13 cannot be increased by the thickness of the lead wire 15, resulting in poor efficiency. ■Since both terminals of the lead wire 15 of the voice coil 10 must be passed through the magnetic gap 13, and both terminals of the lead wire 15 must be soldered to the vibrating body 9, etc., it is not suitable for mass production and is expensive. It had become a thing. ■Also, if the vibrating body 9 is made of the thin film plastics of today, if you try to solder the terminals of the lead wires 15 to it, holes will open due to the heat generated at that time, increasing the defective rate. The vibrating body 9 cannot be formed of plastic,
It could not be mass-produced cheaply. ■Also, since both terminals of the lead wire 15 of the voice coil 10 are passed through the magnetic gap 13, there is a risk that the lead wire 15 may come into contact with the fixed side when the voice coil 10 vibrates, so it must be manufactured with great precision. The defective rate was also very high.

In addition, in the case of the conventional speaker 1, since the voice coil 10 is vibrated, the specific gravity of the conducting wire that makes up the voice coil 10 (the specific gravity of copper is

About 7), the load is heavy, the response speed is slow, and the audio signal cannot be extracted with high precision over a wide range. In particular, it wasn't good enough to extract dynamic bass. (2) In addition, in order to eliminate the drawback (2) above due to the extremely heavy conductor wire for forming the voice coil 10, in other words, the weight of the voice coil 10 is not increased and the magnetic gap 13 is widened to In order to prevent the magnetic flux density in the air gap 13 from decreasing, the conductor wires must be tightly wound in a single row so as not to overlap, or the wires must be wound in a manner known as aligned winding. Like this 1
Manufacturing the voice coil 10, which is tightly wound in rows, requires very high precision and is difficult, resulting in a high defect rate and high cost. (1) One of the causes of the drawbacks (2) and (2) above is that in conventional speakers 1, etc., the resistance value of the voice coil 10 is, for example, 1 depending on the standard.

This is due to the fact that it is specified as 8Ω, etc. However, manufacturing the voice coil 10 according to the resistance value is extremely troublesome and has the disadvantage of not being suitable for mass production.

In addition, as described above, the voice coil 10 must be formed by tightly winding it in one row, which makes it impossible to wind the conductive wire in multiple turns, which results in the generation of a large driving force to vibrate the voice coil 10. Therefore, in the case of low-pitched sounds, it was not possible to output audio signals with high accuracy. Also,
In particular, when trying to produce bass sounds with high precision, the precision becomes extremely high.

It has not been possible to produce a speaker or the like that can produce accurate bass sounds at low cost.

Note that the large driving force T for vibrating the voice coil 10 is as follows.

T = t・t: Number of winding turns of the conductor ■: Lightning current is given, but conventionally, the number of winding turns t of the conductor cannot be made to a large value due to the above reasons, so Not only is it impossible to obtain driving force, but
This has the drawback that the value of the current I also increases, resulting in an inefficient speaker 1.

Furthermore, according to the speaker 1, the field section (magnetic circuit) 6
As is clear from Fig. 6, this method requires the use of a large and heavy permanent magnet 4, which results in a heavy object. had the disadvantage of being expensive.

In addition, since the large permanent magnet 4 is used as described above, the permanent magnet 4 must be exposed and attached, so that a considerable amount of the magnetic flux of the permanent magnet 4 leaks, that is, such a large leakage magnetic flux However, there was a risk that it would have a negative impact on various types of audio equipment, which are becoming increasingly densely packaged.

In addition, since the large permanent magnet 4 must be exposed and mounted as described above, a considerable amount of the magnetic flux of the permanent magnet 4 leaks, resulting in an inefficient speaker 1, which requires the use of a large and heavy permanent magnet. Otherwise, a large amount of expensive permanent magnet material capable of forming a strong magnetic force must be used, which increases the disadvantage that the speaker 1 becomes large, heavy, and expensive.

[Objectives of the present invention] The object of the present invention is to completely change the concept of conventional electrodynamic electroacoustic exchangers and move the field magnet without moving the voice coil.

The objective was to provide an electrodynamic electroacoustic exchanger that would have a long life and be highly reliable by eliminating breakage of the lead wires caused by the vibration of the voice coil dragging the lead wires and damage caused by solder coming off. In addition, the lead wire does not need to pass through the magnetic gap 13, and the troublesome process of soldering both terminals of the lead wire to the vibrating body, etc., is omitted, making it suitable for mass production and manufacturing at low cost. This was accomplished with the task of achieving this goal. Another problem of the present invention is that by creating a configuration in which the voice coil does not move, the lead wire does not come into contact with the stationary side.
By making the transducer lighter, the response speed is faster, and audio signals can be extracted over a wider range with higher accuracy. The goal was to create a device that could produce especially dynamic bass sounds at a low cost. Namely.

By using a method that moves the field magnet, it is possible to prevent the field magnet from becoming a large load, and also to generate a strong magnetic force.Even if a magnetic material capable of generating such a strong magnetic force is used, The object of this invention is to make the field magnet small and light in weight so that the field magnet can be constructed at low cost. In addition, by creating a configuration that does not require the voice coil to move, it is possible to use flat winding, which eliminates the need for the close winding method of winding conductors in a single row so that they do not overlap, which is extremely difficult to manufacture. In this way 1
This was accomplished with the objective of making winding manufacturing extremely easy, reducing the defective rate, and making it possible to mass-produce voice coils at low cost and easily. Of course, in the present invention, it goes without saying that the voice coil of a conventional speaker may be used as is.Also, the voice coil is structured to have a sufficient space to accommodate the voice coil wound with a large number of turns. By eliminating the need to form densely wound windings in one row and using a voice coil formed by winding many turns of conducting wire, it is possible to generate a large driving force to vibrate the field magnet, thereby producing low-pitched sounds. The object of this invention was to make it possible to extract highly accurate audio signals even in the case of .

By doing this, the number of winding turns t of the conducting wire can be set to a large value in terms of the large driving force T for vibrating the field magnet. By forming it in the following manner, it is possible to obtain a large driving force T, and by making it possible to reduce the value of the current ■, it is possible to obtain an efficient electrodynamic electroacoustic exchanger such as a speaker. The task was to do so.

Yet again. By simplifying the magnetic circuit configuration.

By minimizing the leakage magnetic flux of the field magnet, the structure is configured so that external equipment is not adversely affected by the leakage magnetic flux of the field magnet, and the magnetic circuit can be configured small, resulting in a lightweight and small speaker. The objective was to make it possible to construct the system at low cost and easily.

[Means for achieving the object of the present invention] The object of the present invention is to fix a stator voice coil formed in a cylindrical shape in a cylindrical magnetic gap of a magnetic circuit, and to connect the stator voice coil with the radial magnetic gap. A field formed by a cylindrical unipolar radially anisotropic neodymium-boron-iron resin magnet whose inner and outer surfaces are magnetized with different polarities so that it can move freely in the axial direction within the magnetic gap. This is achieved by providing a magnetic field magnet and providing a vibrating body that is interlocked with or in contact with the axial vibration movement of the field magnet, either directly or at intervals.

[Embodiments of the present invention] [First embodiment of the present invention] Fig. 1 shows a dynamic cone speaker 16 of the present invention.
FIG. 2 is an exploded perspective view with a part thereof cut away, and FIG. 2 is a longitudinal sectional view thereof. A first embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

A dynamic cone speaker 16 according to a first embodiment of the present invention is manufactured by molding a magnetic material 2, for example, a magnetic material containing plastic powder.

Center ball (center magnetic pole) 17. Yoke plate 18
and by integrally forming the frame 19.

A stator 20 serving as a field section is formed. The center ball 17 is integrally formed with the bottom central portion 18a of the cup-shaped yoke plate 18 and extends upward in a cylindrical shape.
A cylindrical magnetic gap 30 is formed between the outer circumference 17a and the inner circumferential surface 18b of the yoke plate 18. A cone-shaped frame 19 is integrally formed at the upper end of the outer periphery 18c of the cup-shaped yoke plate 18. The peripheral edge of a cone-shaped vibrating body 21 is bonded to the upper edge of the frame 19 with two gaskets (not shown) using an adhesive or the like. The center part of the lower end of this vibrating body 21 has a cone-shaped part 22a at the upper end, and has a thickness of 1 mm or less (this varies depending on the specifications and size of the speaker 16, etc., but in the case of a small speaker 16 etc., the thickness is 0.1 mm or less). A field magnet 22 formed into a cylindrical shape (preferably about 5 mm)
The cylindrical field magnet 22 is made of an anisotropic neodymium-boron-iron magnet (radially and radially), which is coupled to enable reciprocating vibration in the axial direction within the magnetic gap 30. By using a cylindrical magnet made of a resin magnet, one that fully satisfies the spirit of the present invention can be easily formed. Incidentally, an anisotropic magnet is a magnet in which spin orientation is forcibly performed, and can generally be manufactured by applying a strong magnetic field to the magnet material before it hardens. Here, as for the magnetic material forming the f & suitable field magnet 22, the field magnet 22 formed is similar to the stator voice coil 23 described later.
It is desirable to have a magnetic flux density that is lighter than the specific gravity of 1 and that is extremely easy to process or form.For this reason, the field magnet 22 selected and prototyped by the present inventors is.

Neodymium/boron/iron-based resin is anisotropically oriented with a specific gravity of about 4 (radially and radially) so that it can easily produce a strong magnetic force and an extremely thin magnet. A magnet is used and formed into a cylindrical shape by molding means. The field magnet 22 has radial anisotropy and has nine magnetization directions regulated, so it is magnetized into a single pole so that the inner and outer circumferences have different polarities. 91 In this embodiment, the inner periphery is magnetized to the north pole and the outer periphery is magnetized to the south pole. The length of the field magnet 22 in the axial direction is 7 mm in the two types of speakers that were actually prototyped.

The outer diameter is 20mm, but the radial thickness of one side is 1mm.
and the weight is 1g, and the radial thickness of the other is 0.5mm
A material having a weight of 0.5 g was used. As the stator voice coil 23 to be described later, an experiment was conducted using the voice coil 10 shown in FIG. 6, which is used in the conventional speaker 1 and has a weight of 0.5 g and an axial length of 4 mm. went. Which of these two types of field magnet 2
2, it was possible to obtain a device that accurately generated an acoustic signal. The middle part of the field magnet 22 is supported by a damper (not shown) for holding the field magnet 22 at the center of the magnetic pole and applying appropriate damping (braking) to vibrations, and the field magnet 22 is held at the center of the magnetic pole. It is made to be positioned correctly within the magnetic air gap 30. Further, a dust cap 24 such as a dustproof cloth is attached to the upper surface of the central portion of the vibrating body 21 to prevent dust in the air from entering the magnetic gap 30. A stator voice coil 23 formed into a cylindrical shape by winding a conductive wire with an appropriate number of turns is fixed to the inner circumferential surface 18b of the yoke plate 18 using adhesive.
is pulled out from a through hole 26 provided in the lower part of the yoke plate 18 and guided to the outside.

[Second Embodiment of the Invention] FIG. 3 shows a dynamic cone speaker 16 of the present invention.
4 is an exploded perspective view of the main parts of 1.

With reference to FIGS. 3 and 4.

A second embodiment of the present invention will be described below. In addition.

Portions common to those in the first embodiment are denoted by the same reference numerals, and explanations thereof are omitted, and corresponding portions are denoted by dashes.

A dynamic cone speaker 16° showing a second embodiment of the present invention has a cup-shaped center ball 17′, a yoke plate 18′, and a frame 19° integrally formed by pressing a magnetic material such as an iron plate. By doing so, a stator 20' serving as a field section is formed. In order to reduce weight and cost, the center ball 17° is integrally formed into a cup shape by pressing means so that the inside is hollow at the center of the bottom surface of the cup-shaped yoke plate 18'. It is extending. Center ball 17'
A cylindrical magnetic gap of 3 degrees is formed between the outer circumference of the yoke plate 18 and the inner circumference of the yoke plate 18. A cone-shaped frame 19 is attached to the upper end of the 18° outer circumference of the cup-shaped yoke.
° is integrally formed. A through hole 27 is formed in the frame 19'' by pressing means.

Further, two flanges each having a through hole 28 are formed on the upper edge of the frame 19'' to connect the circumferential edge of the cone-shaped vibrating body 21' with a screw or the like together with a gasket (not shown). In the vibrating body 21° in the example,
In order to increase the vibration efficiency, a bellows portion 31 is formed in the middle. The configuration of the other parts of this speaker 16° is the same as that shown in the first embodiment, so a description thereof will be omitted. Note that the reference numeral 26' indicates a through hole.

[Third Embodiment of the Present Invention] In this third embodiment, referring to FIG.
FIG. 5 shows an example in which the field magnet 22 and the field magnet 22 are formed simultaneously by two-color molding of plastic and a plastic magnet, or one of them is molded first and then the other is formed integrally. Needless to say, the vibrating body 21'' is made of plastic.

[Operation of the invention] In the present invention, the principle of operation is the same, so to explain it with reference to the first embodiment, in the speaker 1,
When an alternating current with a magnitude based on the acoustic signal is passed through the voice coil 23, a force that reciprocates along the axial direction of the magnetic air gap 30 is generated according to Fleming's left-hand rule, so the field magnet 22 is connected to the magnetic air gap. 30 and reciprocatingly vibrates along its axial direction. For this reason, the field magnet 2
A vibrating body 21 fixed to 2 vibrates to generate an acoustic signal sound having an appropriate wavelength and size.

[Effects of the Invention] Since the present invention has the above configuration, the field magnet moves without moving the voice coil.
It is possible to obtain a highly reliable and long-life electrodynamic electroacoustic exchanger that is free from breakage of the lead wires due to vibration caused by dragging the lead wires and damage due to solder coming off. Furthermore, since the troublesome process of soldering both terminals of the lead wire to the vibrating body or the like can be omitted, mass productivity is excellent and manufacturing can be carried out at low cost. Furthermore, since the lead wire terminals do not need to be soldered to the vibrating body, the vibrating body can be easily mass-produced at low cost using a desirable thin film plastic. In addition, field magnets are made of radially anisotropic neodymium, boron, and iron-based resin magnet materials that have a lighter specific gravity than conductive wire and can generate stronger magnetic force, so field magnets can generate strong magnetic force. Since the amount of magnetic material used is small, the weight of the vibrator is reduced, the response speed is increased, and audio signals can be extracted over a wide range with higher accuracy, which was difficult to do in the past.

In particular, it has the effect of being able to construct a highly efficient device that can extract dynamic bass sounds at low cost. In addition, since field magnets are small and extremely light in weight, magnetic circuits can be constructed very easily, and the magnetic path of the field magnet can be sufficiently closed, reducing magnetic flux leakage due to the field magnet. This has the effect of not adversely affecting the external device of the speaker. In addition, field magnets can have magnetic circuits that generate only a small amount of leakage magnetic flux, so even if neodymium, boron, or iron-based resin magnets are used, which have a higher cost per duram than ferrite magnets, field magnets Since the thickness is very thin and the weight is light, the amount of magnetic material used to form the field magnet is small, which has the effect that the field magnet can be formed at a low cost.

It also simplifies the magnetic circuit including the field magnet.

Since it can be made small and lightweight, it has the effect that an electrodynamic electroacoustic exchanger such as a speaker can be made small and lightweight. Furthermore, there is enough space and
Since the voice coil does not need to be moved, it is possible to manufacture single windings, which eliminates the need to use the close winding method of winding conductors in a single row so that they do not overlap, which is extremely difficult to manufacture. This has the effect of greatly simplifying the process, reducing the defective rate, and making it possible to mass-produce the voice coil at low cost and easily.

Yet again. The field magnet is made of a magnetic material that can generate strong magnetic force even if it is thin (especially recent technology has made this possible), and a voice coil wound with many turns can be used, making it possible to generate a strong magnetic force using a large number of conducting wires. By using a turn-wound voice coil to generate a large driving force to vibrate the field magnet, it is possible to extract highly accurate audio signals even at low frequencies. There is.

In other words, the large driving force for vibrating the field magnet T T = t・■ t: Number of winding turns of the conducting wire ■ = Current, since the number of turns t of the conducting wire can be made to a large value,
Since a large driving force T can be obtained and the value of the current I can also be made small, there is an effect that an efficient electrodynamic electroacoustic exchanger such as a speaker can be obtained. In the two embodiments of the present invention, the speaker was mainly explained, but the present invention is naturally applicable to an electrodynamic electroacoustic exchanger such as a microphone having a common structural principle.

[Brief explanation of the drawing]

FIG. 1 shows a dynamic cone according to a first embodiment of the present invention.
FIG. 2 is a vertical sectional view of the speaker, FIG. 3 is an exploded perspective view of the main parts of a dynamic cone speaker according to a second embodiment of the present invention, and FIG. 4 is a vertical sectional view of the same, FIG. 5 is a partial explanatory diagram for explaining the third embodiment of the present invention, and FIG. 6 is a diagram of a conventional dynamic cone.
A vertical cross-sectional view of the speaker, and FIG. 7 is an explanatory view of the same portion. [Explanation of symbols] 1...Dynamic cone speaker. 2...Center ball (center magnetic pole). 3...Center ball, 4...Permanent magnet. 5... Upper yoke plate, 6... Field section. 7...Frame. 8... Gasket (arrow paper), 9... Vibrating body. 10...Voice coil. 11... Coil bobbin, 12... Damper. 13...Magnetic gap. 14...Dust cap. 15... Lead wire. 16.16', 16'''...Dynamic cone speaker. 17.17'...Center ball. 17a...Outer circumference. 18.18'...Yoke plate. 18a...Bottom part, 18b... Inner peripheral surface. 18c... Outer circumference. 19.19'... Frame. 20.20'... Stator. 21.21'... Vibrating body. 22... Field magnet 22a... Cone shaped part. 23... Stator voice coil. 24... Dust cap. 25... Lead wire. 26.27.28... Through hole. 29... Flange, 30... ...Magnetic air gap.

Claims (1)

[Claims] A cylindrical stator voice coil is fixedly provided in a cylindrical magnetic gap of a magnetic circuit, and is movable in the axial direction within the magnetic gap via a radial magnetic gap with the stator voice coil. A field magnet made of a cylindrical unipolar radially anisotropic neodymium/boron/iron-based resin magnet whose inner and outer surfaces are magnetized with different polarities is installed in the axial direction of the field magnet. An electrodynamic electroacoustic exchanger in which a vibrating body that interlocks with or comes into contact with is provided directly or at intervals.