JPH09102999A - Electromagnetic coupling speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To arrange a coil to be induced in a proper space inside a magnetic gap by easily bonding acoustic radiating elements at proper positions by supporting and fixing the elements on a yoke through gell-state adhesive object having flexibility and surface viscosity. SOLUTION: An element 11 and the upper part of a pole 1 are fixed by an elastic object 16. Since the elastic object 16 has flexibility and surface viscosity, by interposing the elastic object 16, the element 11 and the pole 1 are adhered and the positions of both the element and the pole can be surely held. Besides, the adhesion due to the elastic object 16 eliminates difficulty in comparison with the conventional fixing method, and the element can be easily bonded at the proper position. Thus, the acoustic radiation area of a speaker is not decreased by the increase of adhering area in plane direction and the element is not adhesively fixed only around a hole so that the position can not be deviated in the plane direction. Therefore, the acoustic action is neither limited nor troubled. Further, the speaker having satisfactory acoustic output characteristics can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetically coupled speaker used in various audio equipment.

[0002]

2. Description of the Related Art In an electromagnetically coupled speaker, a voice current (electrical signal) is generated in a magnetic gap formed by a magnetic circuit.
, And a guided coil whose both ends are short-circuited for driving the dome-shaped acoustic radiating element are arranged to face each other, and the guided coil is mechanically independent of the voice coil. And is dielectrically coupled. The "mechanical independence" here may mean, for example, an action via air or another fluid (magnetic fluid or the like) present in the magnetic gap between the voice coil and the induced coil,
It means that there is no mechanically linked movement.

The induction coil is made of a conductor that electrically acts as a one-turn coil. The induction coil and the acoustic radiating element are made of an appropriate conductive material, generally a metal. The induction coil is formed integrally with or connected to the end of the dome-shaped acoustic radiation element. The acoustic radiating element having the guided coil formed at the end is suspended on the yoke forming the magnetic circuit so that the portion of the guided coil is located in the magnetic gap.

In operation, when a voice current is applied to the voice coil via the input terminal, the induced coil acts as a secondary winding in the transformer, which produces an induced current in the induced coil. A driving force is generated in the induced coil due to the interaction with the magnetic flux formed by the permanent magnet and the yoke forming the magnetic circuit. By driving the induction coil in this way, the acoustic radiation element coupled or integrated with the induction coil is driven, and acoustic radiation corresponding to the input voice current to the voice coil is obtained. Therefore, in such an electromagnetically coupled speaker, it is important that the respective constituent elements are correctly arranged in space.

An example of the structure of a conventional electromagnetically coupled speaker will be described with reference to FIG. The speaker shown in the figure has a support plate 22 having a center pole (yoke) 21 projecting upward in the central portion, and an annular magnet 23 which is mounted and fixed on the support plate 22 by being inserted into the center pole 21. , An annular upper plate 24 mounted and fixed on the magnet 23. The center pole 21, the support plate 22, and the magnet 2 are provided.
The magnetic circuit unit 25 is configured by the upper plate 3 and the upper plate 24. The magnetic gap is the center pole 2 above.
1 and the upper plate 24.

Above the center pole 21, a dome-shaped acoustic radiating element 31 having a cylindrical skirt 30 which is an induced coil is formed at the end so that the skirt 30 is disposed in the magnetic gap. Suspended.

Further, the lower end side of a cylindrical coil bobbin 26 having an inner diameter larger than the outer diameter of the center pole 21 is vertically movable above the center pole 21 so as to include the acoustic radiation element 31. It is fitted loosely. The coil bobbin 26 is properly arranged by joining the other end of a damper 28, one end of which is connected to a frame 29 mounted and fixed on the upper plate 24, to the upper side surface. Then, the center pole 2 of the coil bobbin 26 is arranged so as to be arranged in the magnetic gap.
Outside the part that is loosely fitted to the upper part of 1, the voice coil 2
7 are wound.

On the outer periphery of the upper side surface of the coil bobbin 26, a lower peripheral edge portion of a vibration plate 32 having an inner diameter gradually increasing upward is joined.
The upper peripheral edge of 2 is connected to the peripheral edge of the frame 29 by a ring-shaped edge 33 and a gasket 34. Further, a dustproof cap 35 is attached to the upper portion of the coil bobbin 26 to prevent dust and the like from being adsorbed.

FIG. 5 shows in detail a general supporting and fixing method of the acoustic radiation element 31 suspended above the center pole 21 to the center pole 21. In this case, a hole is provided in the center of the acoustic radiating element 31, the tip of the fixing member 36 whose lower end is fixed to the upper part of the center pole 21 penetrates through this hole, and the adhesive 37 is provided around the hole. The acoustic radiating element 31 is fixed to the center pole 21 by being applied and adhered.

[0010]

However, the method of fixing the acoustic radiating element 31 described above has the following problems. The acoustic radiating element 31 is merely bonded to the fixing member 36 by a hole provided in the center thereof. Therefore, it is very difficult to join the acoustic radiating element 31 to a proper position, that is, it is difficult to dispose the skirt 30, which is an induced coil formed at the end of the acoustic radiating element 31, at a proper position in the magnetic gap. Become.

To provide a hole in the acoustic radiating element 31,
The acoustic radiation area is reduced, and since the adhesive is fixed only around the hole, its acoustic behavior is limited and hindered.

The fixing by the fixing member 36 cannot suppress the natural resonance determined by the shape and material of the acoustic radiating element 31. Therefore, in order to obtain good sound output characteristics, as shown in FIG. 5, a braking member 38 made of glass wool, foam, or the like is provided on the back surface of the acoustic radiating element 31.
Need to be installed.

A step of forming a hole in the acoustic radiating element 31, a step of attaching the fixing member 36 to the center pole 21, a step of applying an adhesive, etc. are required, which increases the number of steps and complicates.

[0014]

In order to solve the above problems, in the electromagnetically coupled speaker according to the first aspect of the present invention, an inductive coil is formed at an end on a yoke forming a magnetic circuit. And a dome-shaped acoustic radiation element driven by the guided coil is suspended so as to position the guided coil in the magnetic gap formed by the magnetic circuit, and in the magnetic gap and In an electromagnetically coupled speaker in which a voice coil that guides the induced coil by inputting an electric signal is arranged outside the induced coil, the acoustic radiating element has flexibility and surface adhesiveness. It is characterized in that it is supported and fixed to the yoke by a gel-like viscoelastic body.

The electromagnetically coupled speaker according to a second aspect is characterized in that, in the structure according to the first aspect, the gel-like viscoelastic body contains a polyolefin polyol-isocyanate cured product as a main component.

According to the present invention, the acoustic radiation element is supported and fixed to the yoke by the gel-like viscoelastic body.
As the gel-like viscoelastic body, as described in claim 2, one having a polyolefin polyol-isocyanate cured product as a main component is used. Since the gel-like viscoelastic body has flexibility and surface adhesiveness, by interposing the gel-like viscoelastic body, the acoustic radiating element and the yoke are closely attached,
Both positions are easily and reliably retained. And the adhesion by the gel-like viscoelastic body has a large contact area in the surface direction,
Since there is no displacement in the plane direction, compared to the conventional fixing method using holes and fixing members, it is easier and easier to join the acoustic radiating element to the proper position, that is, the induced coil connected to this is connected. It becomes possible to spatially arrange at an appropriate position in the magnetic gap.

Further, since the acoustic radiating element can be fixed to the yoke without making a hole in the central portion of the acoustic radiating element, the acoustic behavior which is received by reducing the acoustic radiating area or by fixing the acoustic radiating element only around the hole. There are no restrictions or obstacles.

Further, since the gel-like viscoelastic body is adhered to the longitudinal direction due to the flexibility of the gel-like viscoelastic body, the natural resonance on the acoustic radiating element is suppressed,
Since the frequency characteristic which is the influence output is flattened, a good acoustic output characteristic can be obtained without separately disposing a braking material on the back side of the acoustic radiating element as in the conventional case.

Further, since there is no need for a step of making holes in the acoustic radiation element, a step of attaching a fixing member to the yoke, a step of applying an adhesive, etc., the number of steps can be reduced and simplification can be achieved.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, the electromagnetic coupling type loudspeaker according to the present embodiment has a support plate 2 having a center pole (yoke) 1 projecting upward in the center, and a center pole on the support plate 2. 1 is provided with an annular magnet 3 which is inserted and fixed on the magnet 1, and an annular upper plate 4 which is mounted and fixed on the magnet 3. The center pole 1, the support plate 2, and the magnet 3 are provided. , And the upper plate 4 constitute a magnetic circuit section (magnetic circuit) 5. The magnetic gap is formed between the center pole 1 and the upper plate 4.

A cylindrical skirt 1 which is made of a conductive material and has an induction coil at its end is formed on the center pole 1.
A dome-shaped acoustic radiating element 11 having a 0 formed therein is suspended so as to dispose the skirt 10 in the magnetic gap. The fixing method for supporting and fixing the acoustic radiating element 11 to the center pole 1 will be described later.

The lower end of a cylindrical coil bobbin 6 having an inner diameter larger than the outer diameter of the center pole 1 is vertically movable above the center pole 1 so as to include the acoustic radiating element 11. It is fitted loosely.
The coil bobbin 6 has a damper 8 whose one end is connected to a frame 9 mounted and fixed on the upper plate 4.
The other end is joined to the upper part of the side surface so that it is properly arranged. The voice coil 7 is wound outside the portion of the coil bobbin 6 which is loosely fitted to the upper portion of the center pole 1 so as to be arranged in the magnetic gap.

On the outer periphery of the upper side surface of the coil bobbin 6, a lower peripheral edge portion of the vibration plate 12 formed so that the inner diameter thereof gradually widens upward is joined.
The upper peripheral edge of 2 is connected to the peripheral edge of the frame 9 by a ring-shaped edge 13 and a gasket 14. Further, a dustproof cap 15 is attached to the upper portion of the coil bobbin 6 to prevent the adsorption of dust and the like.

In operation, when a voice current is applied to the voice coil 7 via an input terminal (not shown), the skirt 10 acts as a secondary winding in the transformer and the skirt 10
An induced current is generated in the skirt 10, and a driving force is generated in the skirt 10 due to the interaction between this current and the magnetic flux formed by the magnet 3 and the center pole 1 included in the magnetic circuit section 5. By driving the skirt 10 in this manner, the acoustic radiation element 11 integrated with the skirt 10 is driven, and acoustic radiation corresponding to the input voice current to the voice coil 7 is obtained.

Here, FIG. 2 shows in detail the method of fixing the acoustic radiating element 11 suspended above the center pole 1 to the center pole 1 in the present electromagnetically coupled speaker. As shown in the figure, in this electromagnetic coupling type speaker,
The acoustic radiating element 11 and the upper part of the center pole 1 are fixed by a gel-like viscoelastic body 16. In the present embodiment, the gel-like viscoelastic body 16 is mainly composed of a polyolefin polyol-isocyanate cured product.

Since the gel-like viscoelastic body 16 has flexibility and surface adhesiveness, the acoustic radiating element 11 and the center pole 1 are closely attached by interposing the gel-like viscoelastic body 16. The positions of both are easily and surely maintained. Further, the adhesion by the gel-like viscoelastic body 16 has a large contact area in the surface direction and is not displaced in the surface direction. Therefore, it is easier and easier than the conventional fixing method using the hole and the fixing member. It is possible to bond the acoustic radiating element 11 to a proper position, that is, to spatially arrange the skirt 10 which is an induced coil connected to the acoustic radiating element 11 at a proper position in the magnetic gap.

Further, since the acoustic radiating element 11 can be fixed to the center pole 1 without making a hole in the central portion of the acoustic radiating element as in the conventional case, the acoustic radiating area is not reduced and the area around the hole is not reduced. Since it is not adhered and fixed only, its acoustic behavior is not limited or hindered.

Furthermore, since the adhesion by the gel-like viscoelastic body 16 has elasticity in the longitudinal direction due to the flexibility of the gel-like viscoelastic body 16, the natural resonance on the acoustic radiating element 11 is suppressed, and Since the frequency characteristic which is the influential output is flattened, good acoustic output characteristics can be obtained without separately disposing a braking material on the back side of the acoustic radiating element as in the conventional case.

Further, since it is not necessary to perform a step of making a hole for the acoustic radiating element, a step of attaching a fixing member to the center pole, a step of applying an adhesive, etc., which have been conventionally required, the number of steps is reduced and simplification is achieved. .

Here, in FIG. 3, the acoustic radiating element 11 and the skirt 10 at the end thereof are molded from aluminum having a thickness of 70 μm, while the gel viscoelastic body 16 has a thickness of 3 mm.
The results of examining the frequency characteristics (change of the sound pressure level with respect to frequency) in the electromagnetically coupled speaker of one example manufactured by punching from the sheet of FIG. In the figure, a solid line a represents a frequency characteristic of the configuration of the present embodiment, and a dotted line b represents a reference for the above-described conventional fixing method (acoustic radiating element). The frequency characteristics of the electromagnetically coupled speaker to which the method of adhering and fixing through holes and fixing members are adopted are shown.
In this case, for comparison, only the method of fixing the acoustic radiating element to the center pole is different, and all other constituent requirements are the same.

As is clear from the comparison of the graphs a and b in the figure, it can be seen that the frequency characteristic is flatter according to the configuration of the present embodiment than the conventional configuration.

[0033]

As described above, in the electromagnetically coupled speaker according to the first aspect of the present invention, the induction coil is formed at the end on the yoke forming the magnetic circuit, and is driven by the induction coil. A dome-shaped acoustic radiating element is suspended so as to position the induced coil in a magnetic gap formed by the magnetic circuit, and is electrically connected in the magnetic gap and outside the induced coil. In an electromagnetically coupled speaker in which a voice coil that guides the induced coil when a signal is input is arranged, the acoustic radiating element is arranged on the yoke by a gel-like viscoelastic body having flexibility and surface adhesiveness. The configuration is supported and fixed.

According to a second aspect of the present invention, there is provided the electromagnetically coupled speaker according to the first aspect, wherein the gel-like viscoelastic body contains a polyolefin polyol-isocyanate cured product as a main component.

With this configuration, the electromagnetically coupled speaker of the present invention has the following effects. That is,
Adhesion with a gel-like viscoelastic body has a large contact area in the surface direction and does not displace in the surface direction, so compared to conventional fixing methods using holes and fixing members, it is easy and easy.
It is possible to bond the acoustic radiating element to an appropriate position and spatially arrange the induced coil at an appropriate position in the magnetic gap.

Further, since the acoustic radiating element can be fixed to the yoke without making a hole in the central portion of the acoustic radiating element as in the conventional case, the acoustic radiating area is not reduced, and the adhesive is applied only around the hole. Since it is not fixed, its acoustic behavior is not restricted or hindered, and good acoustic output is possible.

In addition, since the gel-like viscoelastic body is adhered to the longitudinal direction due to the flexibility of the gel-like viscoelastic body, the natural resonance on the acoustic radiating element is suppressed,
Since the frequency characteristic which is the influence output is flattened, a good acoustic output characteristic can be obtained without separately disposing a braking material on the back side of the acoustic radiating element as in the conventional case.

Further, since it is not necessary to perform the process of making holes of the acoustic radiation element, the process of attaching the fixing member to the yoke, the process of applying the adhesive, etc., which have been conventionally required, the number of processes can be reduced and the process can be simplified.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a configuration of an electromagnetically coupled speaker according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing in detail a method of fixing the acoustic radiation element to the center pole in the electromagnetically coupled speaker.

FIG. 3 is a graph showing frequency characteristics of the electromagnetically coupled speaker and frequency characteristics of a conventional electromagnetically coupled speaker.

FIG. 4 is a sectional view schematically showing the configuration of a conventional electromagnetically coupled speaker.

FIG. 5 is a cross-sectional view showing in detail a method of fixing the acoustic radiation element to the center pole in the conventional electromagnetically coupled speaker.

[Explanation of symbols]

 1 Center pole (yoke, magnetic circuit) 2 Support plate (magnetic circuit) 3 Magnet (magnetic circuit) 4 Upper plate (magnetic circuit) 5 Magnetic circuit part (magnetic circuit) 7 Voice coil 10 Skirt (induced coil) 11 Acoustic radiation Element 16 Gel-like viscoelastic body

Claims (2)

[Claims] 1. A dome-shaped acoustic radiating element having a guided coil formed at an end thereof on a yoke constituting a magnetic circuit and driven by the guided coil, wherein the guided coil is connected to the magnetic circuit. A voice coil that is suspended so as to be positioned in a magnetic gap formed by the above, and a voice coil that guides the induced coil when an electric signal is input is disposed inside the magnetic gap and outside the induced coil. In the electromagnetically coupled speaker as described above, the acoustic radiation element is supported and fixed to a yoke by a gel-like viscoelastic body having flexibility and surface adhesiveness. 2. The electromagnetically coupled speaker according to claim 1, wherein the gel-like viscoelastic body contains a polyolefin polyol-isocyanate cured product as a main component.