JPH01258595A - Speaker - Google Patents

Abstract

PURPOSE:To eliminate a damage due to the cutting of a lead wire or a disconnection is soldering by moving a field magnet without moving a coil and pulling and oscillating the lead wire by the coil. CONSTITUTION:The stator voice coil 23 is disposed in the cylindrical magnetic gap 30 of a magnetic circuit. The field magnet 22 made of a cylindrical and radially anisotropic magnet material having an internal and an external faces magnetized to different poles so as to be axially movable in the magnetic gap 30 through this stator coil 23 and the radial magnetic gap 30 is disposed. The end part of an oscillator 21 interlocking with the axial oscillating movement of this field magnet 22 is extended to enclose and protect the field magnet 22 in this extending part. The oscillator 21 is formed of a thin film plastic.

Description

[Detailed Description of the Invention] [Industrial Application Field of the Invention] The present invention relates to a speaker used for acoustic equipment, etc.
The feature is that the coil is fixed and the field magnet moves, which reduces the weight of the movable body, improving the response speed and converting the vibration into sound. It increases efficiency and can easily generate low-pitched sounds.

This eliminates the need to drag lead wires, which promises a long life, and the simplified structure allows mass production at low cost. The reason is that it is a highly efficient speaker.

In particular, the speaker of the present invention has a structure that allows easy integration of the vibrating body and the field magnet, and is excellent in mass production.

[Technical Background and Problems] A speaker is a speaker in which a voice coil is movably disposed within a magnetic field, and when an audio current is passed through the speaker, the voice coil vibrates as the current changes. 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 speaker.
It's called a cone speaker.

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

A permanent magnet 4 made of a cylindrical ferrite magnet is attached to the yoke plate 3. Similarly cylindrical upper yoke plate 5
are arranged and fixed with adhesive etc. to form the field part 6.
The fixed side is configured by configuring . Field part 6 shown here
This is called an external magnetic type, but it may also be an internal magnetic type, which uses a yoke and incorporates a columnar permanent magnet and a center ball in the center of the yoke.

A cone-shaped frame 7 is coupled to this field section 6.
A peripheral edge of a vibrating body 9 formed of a cone-shaped fiber is bonded to the peripheral edge of the frame 7 with an adhesive or the like, along with a gasket (satellite) 8. 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 housed on 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.

Also, the lead #Ji 15 of the voice coil 10 is the seventh
As shown in the figure, both terminals are pulled out from the top through the magnetic gap 13, guided to the vibrating body 9 (or the frame 7), and soldered at that position. ■ Inside the magnetic gap 13 Lead wire 1 of voice coil 10 to
By using the voice coil 10 with a limited thickness to pass both terminals of the lead wire 15, the magnetic flux density within the magnetic gap 13 cannot be increased by the thickness of the lead wire 15, resulting in poor efficiency. Ta. ■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, when the vibrating body 9 is formed of recent thin-film plastic, if the terminal of the lead wire 15 is soldered to it, holes will open due to the heat generated at that time, increasing the defective rate. It was not possible to form a body 9 and mass production was not possible at low cost. ■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

7) is heavy, resulting in a large load, slow response speed, and 1) disadvantages in that it is not possible to collect audio signals with higher accuracy 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 conductive wires must be closely wound in a single row (also called aligned winding) so as not to overlap. 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 above-mentioned drawbacks (2) and (2) is that in the conventional speaker 1, etc., the resistance value of the voice coil 10 is set as 1, for example, 8Ω by the standard.

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 wire I: It is given by the current, but conventionally, the number of winding turns t of the conductor wire 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 peripheral equipment such as audio equipment for each unit, which is trending toward high-density packaging.

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. Alternatively, a large amount of expensive permanent magnet material capable of generating strong magnetic force must be used, which increases the disadvantage that the speaker 1 is large, heavy, and expensive.

In addition, in the case of the conventional speaker 1, since the voice coil 10 is of a movable type, the vibrating body 9 made of paper or fiber and the coil bobbin 11 must be integrated. This method has the disadvantage that it is difficult to connect different materials that have not yet been used, and that it is not suitable for mass production.

[Problems of the present invention] The biggest problem of the present invention will be described later, but first of all, other problems of the present invention will be explained. First, by completely changing the concept of the conventional speaker, the coil does not move, By making the field magnet move, the aim was to eliminate breakage of the lead wires caused by vibration caused by the coil dragging the lead wires, and to create a speaker with long lifespan and high reliability. It is something.

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 configuring the coil so that it does not move, the lead wire does not come into sliding contact with the fixed side.
Also, the field magnet is constructed using a magnetic material with a specific gravity smaller than that of the conductive wire (for example, one with a specific gravity of 4),
By moving this, the weight of the vibrator can be reduced, the response speed can be increased, and audio signals can be extracted over a wide range with more precision, especially dynamic bass. The goal was to create something that could be constructed at a low cost.

In other words, since the field magnet is moved, it is possible to prevent the field magnet from being subjected to a large load, and also to generate a strong magnetic force, and by using a magnetic material that can generate such a strong magnetic force. The object of the present invention is to make it possible to construct a field magnet at a low cost, since the field magnet can be made smaller and its weight can be reduced.

In addition, by creating a configuration that does not require moving the coil,
The conductor wires that were conventionally used to manufacture voice coils, which were extremely difficult to manufacture, were placed closely together so that they did not overlap.
To make it extremely easy to manufacture one winding by adopting a flat winding method that does not require the adoption of a dense winding method of winding the wire in rows, and to reduce the defective rate and make it possible to inexpensively and easily mass-produce the voice coil. It was created with this in mind.

Of course, in the present invention, it goes without saying that the voice coil of a conventional speaker may be used as is.

In addition, the structure is designed to provide enough space to accommodate a coil wound with multiple turns.

The coil does not need to be tightly wound in one row, and a large driving force for vibrating the field magnet can be generated by using a coil in which a conductive wire is wound in many turns. , the objective was to make it possible to extract audio signals with high accuracy even in the case of low-pitched sounds.

By doing this, the large driving force for vibrating the field magnet T T = t-1 t: Number of winding turns of the conductor ■: Current, the number of turns t of the conductor is set to a large value. The objective was to obtain a high-efficiency speaker by making it possible to obtain a large driving force T, and by making it possible to reduce the value of the current I. be.

Yet again. By simplifying the magnetic circuit configuration.

It is easy to make the leakage magnetic flux of the field magnet extremely small, and by configuring it in this way, it is possible to prevent the external equipment from having an adverse effect due to the leakage magnetic flux of the field magnet, and it is possible to configure the magnetic circuit to be small. The object of this invention is to provide a lightweight, small-sized speaker that can be easily constructed at low cost.

In order to satisfy the above-mentioned problems, the biggest problem of the present invention is to make it possible to easily integrate the vibrating body and the driving body so that mass production can be carried out at low cost.

[Means for achieving the object of the present invention] The object of the present invention is to provide a stator coil fixedly within a cylindrical magnetic gap of a magnetic circuit, and to connect the inside of the magnetic gap via the stator coil and a radial magnetic gap. axially)
A vibrating body is provided with a field magnet made of a cylindrical radially anisotropic magnet material whose inner and outer surfaces are magnetized with different polarities so as to be movable, and which is interlocked by the axial vibration movement of the field magnet. This can be achieved by integrating the vibrating body and the field magnet by extending the end of the field magnet and wrapping and protecting the field magnet in the extended part. This can be achieved by forming.

[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 a longitudinal cross-sectional view of the same, and FIG. 3 is an enlarged view of the connecting portion between the vibrating body and the field magnet. A first embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

A dynamic cone speaker 16 according to a first embodiment of the present invention is manufactured by molding a magnetic material 1, for example, a magnetic material containing plastic powder.

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

A stator 20 serving as a field section is formed. The center pole 17 is integrally formed with the bottom central portion 18a of the cup-shaped yoke plate 18 and extends upward in a cylindrical shape.
Two cylindrical magnetic spaces 1! between the outer circumference 17a and the inner circumference surface 18b of the yoke plate 18! It forms Ji30.

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 upper peripheral edge of the frame 19 is provided with a gasket (not shown) as well as a thin film of plastic (it may be made of paper, fiber, etc., but in this case, for the purpose of improving mass production, an example in which a thin film of plastic is used is shown). ) The peripheral edges of the cone-shaped vibrating body 21 are joined together by adhesive, ultrasonic welding, or the like. The connection between the vibrating body 21 made of thin film plastic and the field magnet 22 made of a plastic magnet is achieved by further extending the lower end of the vibrating body 21, and wrapping and protecting the field magnet 22 by this extension 21a. By integrating the field magnet 22 and the extension part 21a using appropriate means such as ultrasonic welding or adhesive, the field magnet 22 and the extension part 21a are connected and fixed so that they can vibrate together.

In addition, depending on the means for connecting and fixing the field magnet 22 and the extension part 21a, a plastic magnet forming the field magnet 22 (not limited to a plastic magnet, but in order to reduce the specific gravity value of the field magnet 22) may be used. (In this embodiment, a plastic magnet is used.) It is preferable to wrap and protect the plastic magnet with an extension 21a and then apply a predetermined magnetization to the plastic magnet to form the field magnet 22. The vibrating body 21 made of thin film plastic can be formed using an appropriate method and material.

Easy to form. For some types of vibrating body 21, a speaker 1 with various tones with various characteristics can be created by selecting a vibrating body 21 with many fine holes, or by changing the material and thickness of the vibrating body 21.
6 can be formed. Although the field magnet 22 used in this embodiment has a cone-shaped portion 22a at its upper part, it may also have a cylindrical shape, and its thickness may vary depending on the specifications and size of the speaker 16, but it may be small. speaker 1
6 etc., it is preferable to form it to about 0.5 mm.

In order to obtain a uniform driving force, the field magnet 22 is desirably formed with an axial length longer than the axial length of the stator voice coil 23, which will be described later.6 The cylindrical field magnet 22 is .

By using a cylindrical magnet made of a radially (radially) anisotropic resin magnet, for example, neodymium, boron, or iron, it is possible to easily form a magnet that fully satisfies the purpose of the present invention.

Furthermore, an anisotropic magnet is a magnet in which the spin orientation is forcibly applied.
It can be produced by applying a strong magnetic field. Here, the optimum magnetic material for forming the field magnet 22 is such that the formed field magnet 22 has a magnetic flux density that is lighter and 1 stronger than the specific gravity of the stator voice coil 23, which will be described later.

Moreover, it is desirable to have something that is extremely easy to process or form.
For this purpose, 1. Field magnet selected and prototyped by the inventor 2.
2, so that a strong magnetic force can be obtained as a magnet and an extremely thin one can be easily obtained.
Using a radially anisotropically oriented neodymium/boron/iron resin magnet with a specific gravity of about 4,
This is formed into a cylindrical shape by a suitable forming means such as a mold. The field magnet 22 has radial anisotropy and one magnetization direction is regulated, so it is magnetized into a single pole so that the inner and outer circumferences have different polarities. In this embodiment, the inner circumference is the N pole and the outer circumference is the S pole.
It is a single-pole type with magnetization formed on the pole. If the weight of the field magnet 22 becomes heavy, the responsiveness will deteriorate, so it is desirable to use a field magnet 22 that is less than three times the weight of the stator voice coil 23, which will be described later. The two types of speakers we actually prototyped had an axial length of 7 mm and an outer diameter of 20 m.
One of them had a radial thickness of 1 mm and a weight of 1 g, and the other had a radial thickness of 0.5 mm and a weight of 0.5 g. 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. When the voice coil 10 of 0.5 g is used as the stator voice coil 23, the field magnet 22
, 085 g, the weight of the field magnet 22 is twice the weight of the stator voice coil 23, respectively. No matter which of these two types of field magnets 22 was used, it was possible to obtain an accurate and accurate acoustic signal. However, when the field magnet 22 is constructed using the above-mentioned type of magnet material, a stronger magnetic flux can be obtained by using a lighter field magnet 22 with a thickness of 0.5 mm and a weight of 0.5 g. Good results have been obtained.

Therefore, when the conventional voice coil 10 is used as the stator voice coil 23, the field magnet 22 is
If a coil having approximately the same weight as the voice coil 10 is used, a highly efficient speaker 16 that can be expected to be obtained can be obtained. It should be noted that a more desirable stator voice coil 23 can further improve its performance by reducing its axial length and reducing its weight. In this way, a large acoustic signal can be obtained, and the weight of the speaker 16 can be reduced.

In addition, the field magnet 22 is held at the center of the magnetic pole and appropriately supported using a damper in order to apply appropriate damping (braking) to vibration, and the field magnet 22 is properly placed within the magnetic gap 30 of the field section. It would be more convenient to have it positioned, but it is also possible without it. In the actual prototype,
A prototype was made without using a damper, but there was no effect. 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 conducting wire with an appropriate number of turns is fixed to the inner peripheral surface 18b of the yoke plate 18 using adhesive, and the field magnet 22 and the magnetic air gap 23 are fixed to the inner peripheral surface 18b of the yoke plate 18. They are facing each other through the A through hole 26 provided in the lower part of the yoke plate 18 for the lead wire 25 of the stator voice coil 23
It is pulled out from the body and guided to the outside.

[Second Embodiment of the Invention] FIG. 4 shows a dynamic cone speaker 16 of the present invention.
Fig. 5 is an exploded perspective view of the main parts of 1.

With reference to FIGS. 4 and 5.

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 their explanations are omitted, and corresponding portions are denoted with a dash.

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 portion 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''. A cylindrical magnetic gap 30 is formed between the outer circumference of the center ball 17'' and the inner circumference of the yoke plate 1-18'.The upper end of the outer circumference of the cup-shaped yoke 18'' Cone-shaped frame 1
9゛ is integrally formed. A through hole 27 is formed in the frame 19' by pressing means.

Further, a flange 29 having a through hole 28 is formed on the upper edge of the frame 19' to connect the 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.

[Operation of the invention] In the present invention, the principle of operation is the same, so to explain 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.
This eliminates breakage of the lead wires caused by vibration caused by dragging the lead wires and damage due to solder coming off, making it possible to obtain a highly reliable and long-life speaker. 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 material, such as neodymium, boron, or iron-based resin magnets, which have a lighter specific gravity than conductive wires and can strengthen magnetic force, and are 3 times the weight of the stator voice coil.
The field magnet can generate a strong magnetic force, and the amount of magnetic material used is small, so the weight of the vibrator is light. This has been difficult in the past because the response speed is faster and audio signals can be extracted over a wider range with higher accuracy. 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, by increasing the length of the field magnet in the axial direction of the stator voice coil, sufficient magnetic flux can be obtained, making it possible to more reliably obtain driving force.
As a result, it is possible to extract the audio signal with higher precision, so that it is possible to construct a highly efficient device that can extract particularly dynamic bass sounds at a 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, the field magnet is
Because the magnetic circuit can be configured so that only a small amount of leakage magnetic flux is generated, even if neodymium, boron, or iron-based resin magnets that generate strong magnetic force are used, which have a higher cost per duram than ferrite magnets, field magnets cannot be used. Because it is extremely thin and light in weight,
Since the amount of magnetic material constituting the field magnet is small, the field magnet can be formed at low cost.

It also simplifies the magnetic circuit including the field magnet.

Since it can be formed to be small and lightweight, there is an effect that the speaker can be formed small and lightweight as a result.

Furthermore, since there is sufficient space and the voice coil does not need to be moved, it is not necessary to adopt the close winding method of winding the conductors closely in a single row to avoid overlapping the conductors, which is extremely difficult to manufacture. Since it is possible to use empty windings, it is extremely easy to manufacture nine windings, which reduces the defective rate and allows the voice coil to be mass-produced 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, a large driving force T to vibrate the field magnet T = t・■ t: Number of winding turns of the conductor ■: In terms of current, the number of turns t of the conductor can be made to a large value, so
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 a highly efficient speaker can be obtained.

The greatest effect of the present invention, which can derive the above effects, is that it utilizes a part of the vibrating body.

Since the field magnet is wrapped and protected, it is very easy to connect and fix the vibrating body and field magnet.

In this case, if the vibrating body is made of thin film plastic, the vibrating body can be used very easily.
Since it is extremely easy to connect the vibrating body made of thin film plastic to the field magnet, the speaker can be mass-produced at low cost. Yet again. In this way, rust can be prevented in the case of materials that rust easily, such as neodymium, iron, and boron-based magnets, and also in the case of rare earth-based magnets.

In the case of a magnet that is brittle and generates magnetic powder from its surface, there is an advantage that the generation of magnetic powder can be prevented, and deterioration of the field magnet can be prevented.

1. In the above embodiment of the present invention, an example of a speaker using a stator voice coil and a single-pole field magnet was shown, but a toroidal stator coil different from the stator voice coil and a plurality of poles attached in the axial direction were used. A type of speaker using a magnetized field magnet may also be used.

Further, in the above embodiment, an example was shown in which the magnetic air gap of the magnetic circuit was formed in a cylindrical shape, but it goes without saying that a magnetic circuit configuration in which a polygonal cylindrical magnetic air gap is formed may also be used.

[Brief explanation of the drawing]

FIG. 1 shows a dynamic cone according to a first embodiment of the present invention.
2 is a vertical sectional view of the speaker, FIG. 3 is a partially enlarged view of the connecting portion between the vibrating body and the field magnet, and FIG. 4 is the second embodiment of the present invention. FIG. 5 is an exploded perspective view of the main parts of the dynamic cone speaker of the embodiment, and FIG. 5 is a longitudinal sectional view thereof. FIG. 6 is a longitudinal cross-sectional view of a conventional dynamic cone 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 circumference. 18c...Outer circumference. 19.19''...Frame. 20.20'... Stator, 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 gap. Figure 1 Figure 2 Front 3 Figure 4 Figure 5

Claims (2)

[Claims] (1) A stator coil is fixedly provided within a cylindrical magnetic gap of a magnetic circuit, and the inner and outer surfaces are arranged such that the stator coil is movable in the axial direction within the magnetic gap through the radial magnetic gap with the stator coil. A field magnet formed of a cylindrical radially anisotropic magnetic material magnetized with different polarities is provided, and the end portion of the vibrating body that is interlocked is extended by the axial vibration movement of the field magnet. A speaker that integrates a vibrating body and a field magnet by wrapping and protecting the field magnet. (2) The speaker according to claim (1), wherein the vibrating body is made of thin film plastic.