JPH09327089A - Triple coil speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the speaker with s small size at a low cost with a small resonance sharpness Q0 in order to solve problems that a magnetic shield speaker can not sufficiently cope with a requirement of a small resonance sharpness Q0 at a minimum resonance frequency for a small sized low cost speaker and an MFB speaker has a complicated structure and requires a high cost. SOLUTION: The speaker is provided with a center pole 1 implanted in the middle of cone paper 15, voice coils 9a-9c fitted to a bobbin 8 located concentrically to the center pole 1, a drive magnet 6, and a cancel magnet 5 magnetized in opposite polarity to the drive magnet 6. In this case, the three voice coils 9a-9c three plates 32, 33, 34 are arranged in the middle and both sides of the drive magnet 6 and the cancel magnet 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is a compact, low-priced M.
The present invention relates to an FB (motional feedback) speaker, and more specifically, to a triple coil speaker capable of reducing the resonance sharpness Q ₀ at the lowest resonance frequency.

[0002]

2. Description of the Related Art In a small and low-priced speaker, it is necessary to reduce the resonance sharpness Q ₀ at the lowest resonance frequency so that bass reproduction can be advantageously performed by the small bass reflex system.
Resonance sharpness Q ₀ when attached to a small speaker is 0.5
At 8 o'clock, it is known to have the best bass reproduction. For that purpose, it is necessary to reduce the resonance sharpness Q ₀ in the speaker body. However, in general, in a small and low-priced speaker, the resonance sharpness Q _{0 at the} lowest resonance frequency is obtained.
It has been very difficult to reduce. For example, even if the drive magnet is enlarged to increase the magnetic energy, the center pole may be magnetically saturated or expensive.

As another type, a magnetic shield type speaker is known. In this magnetic shield type speaker, a magnet magnetized in the opposite polarity to the drive magnet,
Although a so-called cancel magnet is used, even with such a type, only an increase in magnetic flux of about 10% can be expected.

FIG. 7 is a cross-sectional view showing an example of the structure of the main part of a conventional magnetic shield type speaker. In the figure, 1 is a center pole, 2 is a magnet guide, 3 is a yoke, 4 is a shield cover, 5 is a cancel magnet, 6 is a drive magnet, 7 is a plate, and 8
Is a bobbin, 9 is a voice coil, 10 is a frame, 11 is a damper, 12 is a cap, 13 is a tinsel wire, 14 is an input terminal, 15 is cone paper, 16 is an edge, 17 is a gasket, N is a magnet N The pole and S indicate the S pole.

As shown in FIG. 7, the magnetic shield type speaker comprises a center pole 1 which is erected in the central portion of a cone paper 15, a bobbin 8 which is arranged concentrically with the center pole 1, and The voice coil 9 is attached to the bobbin 8, the driving magnet 6, the cancel magnet 5 and the like. Thus, by using the drive magnet 6 and the cancel magnet 5 magnetized in the opposite polarity, not only the magnetic shield effect but also the magnetic flux in the gap of the magnetic circuit is increased by about 10% and the resonance sharpness Q ₀ is increased. Can be lowered slightly. However, this level is not sufficient, and unsolved problems remain. Further, as another type, an MFB (motional feedback) speaker is also known.

FIG. 8 shows a conventional MFB speaker.
It is sectional drawing which shows an example of the principal part structure. Reference numerals in the drawing are the same as those in FIG. 7, 21 is a driving magnetic circuit, 22 is a driving voice coil, 23 is a driving input terminal, and 24 is M.
FB output terminal, 25 MFB detection coil, 26 MF
A magnetic circuit for B detection, 27 is a magnetic circuit support rod.

As shown in FIG. 8, in the conventional MFB speaker, in addition to the driving magnetic circuit 21, an MFB detecting magnetic circuit 26 is separately prepared and connected to the driving voice coil bobbin or the MFB detecting coil 25. As a result, it is necessary to prepare another coil. Therefore, there is a problem that the structure of the speaker becomes complicated and the cost becomes expensive.

[0008]

As described in the prior art, there is a demand for reducing the resonance sharpness Q ₀ at the lowest resonance frequency in a small and low-priced speaker. However, the magnetic shield type speaker cannot sufficiently meet the request for reducing the resonance sharpness Q ₀ . Further, in the MFB speaker, since the structure of the speaker is complicated and the cost is increased, it is extremely difficult to apply it to a small and low-priced speaker.
An object of the present invention is to reduce the resonance sharpness Q ₀ at the lowest resonance frequency for a small and low-priced speaker.

Specifically, by using a drive magnet and a cancel magnet, the magnetic energy is effectively utilized in the form of a magnetic shield type magnetic circuit as in the case of a so-called magnetic shield type speaker, so that the speaker resonance occurs. The first problem is to reduce the sharpness Q ₀ . Also, like the conventional MFB speaker, a new MFB magnetic circuit and another voice coil are prepared by providing a detection coil for MFB and utilizing magnetic gap energy in a part of the driving magnetic circuit. The second is to increase the energy of the gap of the driving magnetic circuit without
And the subject.

[0010]

According to a first aspect of the present invention, a center pole is set up in the central portion of the cone paper, a voice coil is attached to a bobbin arranged concentrically with the center pole, and a drive is provided. In a speaker including a driving magnet and a cancel magnet magnetized with a polarity opposite to that of the driving magnet, three voice coils and one plate at the center of the driving magnet and one plate on each side of the cancel magnet, for a total of three plates Are arranged.

According to a second aspect of the present invention, in the triple coil speaker of the first aspect, the first voice coil, the second voice coil and the third voice coil are formed by a center pole and three plates. It is arranged at a position facing each gap.

According to the invention of claim 3, the triple coil speaker of claim 1 is provided with a shield cover for covering the outer circumferences of the drive magnet and the cancel magnet.

According to the invention of claim 4, the triple coil speaker of claim 1 is provided with a damper between the bobbin and the shield cover or between the bobbin and the frame or other cover.

According to a fifth aspect of the present invention, the triple coil speaker of the first aspect is provided with dampers between the bobbin and the shield cover, and between the bobbin and the frame and other covers, and the dampers are used as drive magnets and The cancel magnets are arranged symmetrically.

According to a sixth aspect of the present invention, among the three voice coils provided in the triple coil speaker of the first aspect, the position closest to the opening side of the cone paper is the first voice coil, and the central position is the second voice coil. The position farthest from the opening side of the voice coil and the cone paper is the third voice coil, and the direction of the current flowing through the first voice coil and the third voice coil is opposite to that flowing through the second voice coil. ing.

According to the invention of claim 7, among the three voice coils provided in the triple coil speaker of claim 1, the position closest to the opening side of the cone paper is the first voice coil and the central position is the second voice coil. The voice coil, the farthest position from the opening side of the cone paper is the third voice coil, and the first voice coil and the second voice coil are connected in parallel.

According to the invention of claim 8, the three voice coils provided in the triple coil speaker of claim 1 are arranged such that the position closest to the opening side of the cone paper is the first voice coil and the central position is the second voice coil. The voice coil, the farthest position from the opening side of the cone paper is the third voice coil, and the third voice coil is composed of a coil having a diameter smaller than that of the first voice coil and the second voice coil. It is used as a voltage detection coil.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of a triple coil speaker of the present invention will be described with reference to the drawings. According to the present invention, three voice coils are provided and the drive magnet 6 and the drive magnet 6 are provided in order to maximize the energy of the drive magnet 6 and the energy of the cancel magnet 5 to reduce the resonance sharpness Q _0. The cancellation magnet 5 is characterized in that a total of three plates are arranged at the center and both sides of the cancellation magnet 5 (the invention of claim 1).

FIG. 1 is a cross-sectional view showing an example of an embodiment of the main configuration of a triple coil speaker of the present invention. The reference numerals in the figure are the same as those in FIG.
9c is a voice coil, 31 is a lower damper, 32 is a lower plate, 33 is an intermediate plate, 34 is an upper plate, 35 is an upper damper, 36 is an MFB output terminal, 3
7 represents the Kinshi line.

When the speaker is used, the cone is installed in a substantially vertical direction. In the following description, the upper part is referred to as an upper damper 35 and an upper plate 34, and the lower part is referred to as a lower damper 31 and a lower plate 32 in accordance with the drawings. Will be called. As shown in FIG. 1, when the driving magnet 6 and the cancel magnet 5 have the same size, the magnetic fluxes in the three gaps of the magnetic circuit are B1 in order from the upper gap (the top plate 34 and the voice coil 9c). 2 * B
1 and B1. Then, the driving force of the speaker is 4 * B1 because the magnetic gaps in the upper two gaps are added. As for the wire diameter of the coil wound around the voice coils 9c and 9b, since the two coils (9c and 9b) are connected in parallel, the impedance per coil may be doubled. Therefore, the linearity of the wire becomes thin,
Since the resistance doubles, the effective length of the coil increases. Further, since the magnetic flux B1 of the gap is about 1/2 of the magnetic flux B of the ordinary magnetic shield type speaker, the upper two of the three gaps are 3 * B1 and the effective length of the coil is longer. Become. As a result, it can be seen that the resonance sharpness Q ₀ becomes small.

The voice coil 9a is placed in the magnetic flux B1 of the lowermost gap (the lower surface plate 32 and the voice coil 9a).
Are arranged, the coil can be used as a detection coil for the MFB. When it is used as a detection coil for MFB, a large number of thin wires are wound to make several hundred ohms, and the force coefficient of this coil is increased to increase the detection voltage from the coil and reduce the gain of the feedback circuit. It becomes possible and it becomes a stable MFB feedback circuit. This relationship is shown by the following mathematical formula.

[0022]

[Formula 1] Q ₀ = 2πFoReMo / B ² L ² Fo: Minimum resonance frequency of speaker Re: DC resistance of voice coil Mo: Effective mass of vibration system B: Magnetic flux in gap L: Effective length of voice coil in gap Can be expressed as Here, the effective mass Mo of the vibration system
Among them, the weight of the voice coil is about twice the weight of the conventional voice coil, but the mass of the vibration system only increases by about 30%. If calculated on such a premise, the resonance sharpness Q ₀ of the conventional magnetic shield type speaker is half or less, and the structure of the magnetic circuit and the voice coil shown in FIG. 1 is excellent in lowering Q ₀ . It can be said to be a thing.

As a specific numerical example, the conventional speaker has a resonance sharpness Q _{0 of} about 0.8, whereas the speaker of the present invention has Q ₀ when three coils are used.
= About 0.25. At this time, since the magnetic flux in the intermediate gap has the opposite direction, the current flowing through the intermediate coil also has the opposite direction. However, even if the resonance sharpness Q ₀ of the speaker is reduced to this extent, if the effective inner volume of the speaker box is reduced to about 400 cc, the resonance sharpness Q ₀ of the speaker attached to the speaker box is increased,
Bass reproduction becomes difficult.

Therefore, as described above, when the MFB known in the related art is used together, not only the resonance sharpness Q _{0 of the} speaker is changed but also the reproduction band is changed, and the reproduction band of the speaker system is low. It can be expanded to people. As the voltage detection coil for this MFB, of the three coils,
Use the bottom coil. The gap of the magnetic circuit containing this coil is approximately half of the gap in the middle. However, since the resistance value of the coil can be set to a large value, a large number of thin wire rods can be wound, and the detection voltage increases. Further, since the force coefficient F becomes large, in the case of the velocity type MFB, the resonance sharpness Q _{0 of the} speaker can be made small and the variable range of the bass characteristic can be made large. Such effects are the same in the acceleration type and the amplitude type MFB. Here, as an example, the resonance sharpness Q ₀ of the velocity type MFB is shown by an equation.

[0025]

## EQU2 ## Q ₀ ′ = Q ₀ / (1 + A * β * F ′ / F) Q ₀ ′: Resonance sharpness at F ₀ of speaker when MFB is applied Q ₀ : Resonance at F ₀ of speaker Sharpness A: Amplifier gain β: Feedback circuit gain F: Voice coil driving force coefficient F ′: MFB driving coil force coefficient

As described above, according to the present invention, in the small speaker, three plates (32, 33, 34) are used to provide three gaps with the center pole 1 (claims). 1 and the invention of claim 2) In the small speaker, the coils 9a to 9c are wound around three positions of the voice coil bobbin 8 to reduce the resonance sharpness Q ₀ at the lowest resonance bale wave number of the speaker itself (claim). (Inventions 1 to 8). Furthermore, in the small speaker, the coils 9a to 9c are wound around the voice coil bobbin 8 at three positions, and the upper two coils 9b and 9c are wound.
By connecting c in parallel and adding the driving force, and using the lowermost coil 9a as a voltage detection coil for MFB,
A variable operation of the bass characteristic is possible (the invention of claims 7 and 8).

Next, a method of assembling the triple coil speaker of the present invention shown in FIG. 1 will be described with reference to FIGS. 2 to 6. The magnetic circuit is first assembled, and the drive magnet 6, the three plates 32, 33 and 34, and the five components of the cancel magnet 5 are sandwiched to form a single block. . Next, in a separate process, the shield cover 4 is attached to the center pole 1, the lower damper 31, the voice coil 9a.
9c are attached, and then, the drive magnet 6 configured in one block and the three plates 32, 33,
34 and the cancel magnet 5 are fixed. Finally, edged cone paper 15, frame 10, bobbin 8
Voice coils 9a to 9c and tinsel wire 13 wound around
Etc. are attached, and the assembly of the triple coil speaker is completed. First, the drive magnet 6 and the three plates 3
A process of forming the blocks 2, 33, 34 and the cancel magnet 5 into one block will be described.

FIG. 2 shows the triple coil speaker of the present invention shown in FIG. 1, in which the drive magnet 6, the three plates (32, 33, 34) and the cancel magnet 5 are used.
It is a figure showing the state where and were combined. The reference numerals in the figure are the same as those in FIG.

FIG. 3 is a view for explaining a method of assembling the drive magnet 6, the three plates (32, 33, 34) and the cancel magnet 5 shown in FIG. Reference numerals in the figure are the same as those in FIG.
2 is the hole, and 43 is the plate inner diameter guide.

Using the assembly jig 41 as shown in FIG. 3, first, the lower surface plate 32 is put into this jig. Next, an adhesive is applied to the upper surface of the lower plate 32, and the unmagnetized drive magnet 6 is placed and bonded. In this case, the inner diameter of the lower plate 32 determines the center position by the plate inner diameter guide 43 (pole portion) of the assembly jig 41, and the outer diameter of the drive magnet 6 is
The approximate position is determined by the inner diameter of the assembly jig 41. That is, the outer diameter of the drive magnet 6 and the inner diameter of the lower plate 32 are concentric. And
An adhesive is applied to the upper surface of the drive magnet 6, and the intermediate plate 33 is placed. Also in this case, the intermediate plate 33
The inner diameter of the plate inner diameter guide 43 of the assembly jig 41 is
Determine the center position by.

After the adhesive is dried, the cancel magnet 5 is magnetized by a magnetic circuit (not shown) while being kept in the assembly jig 41. On the other hand, the top plate 3
4 and the drive magnet 6 are fixed by adhering them with an adhesive. In this case, the cancel magnet 5 is magnetized to have the opposite polarity to the drive magnet 6. Next, an adhesive is applied to the upper surface of the intermediate plate 33 set in the assembly jig 41, and the cancel magnet 5 is placed on the upper surface of the intermediate plate 33, and the upper plate 34 and the cancel magnet 5 are placed and bonded. Let After the adhesive has dried, the magnetic circuit is taken out from the assembly jig 41.

Through the above steps, as shown in FIG. 1, the three plates 32, 33 and 34, the driving magnet 6 and the canceling magnet 5 are sandwiched and fixed. In a separate step, the shield cover 4, the center pole 1, the lower damper 31,
The bobbin 8 around which the voice coils 9a to 9c are wound is attached in sequence.

FIG. 4 is a diagram for explaining a method of attaching the shield cover 4 and the center pole 1 shown in FIG. Reference numerals in the drawing are the same as those in FIG. 1, and 44 denotes a fixing screw.

As shown in FIG. 4, the shield cover 4
The center pole 1 is attached to the center of the with a fixing screw 44 and the like together with an adhesive. Next, the lower damper 31 and the bobbin 8 around which the voice coils 9a to 9c are wound are attached to the shield cover 4.

FIG. 5 is a view for explaining a state in which the lower damper 31 and the voice coils 9a to 9c are attached to the shield cover 4. The reference numerals in the figure are the same as those in FIG.
Reference numeral 45 is a first voice coil spacer, and 45a is a hole.

First, the first voice coil spacer 4 is attached to the inner diameter of the bobbin 8 around which the voice coils 9a to 9c are wound.
5 is adjusted and the position of each coil 9a is adjusted to a predetermined position of the gap of the magnetic circuit. Then, under the bobbin 8 around which the voice coils 9a to 9c are wound,
Insert the lower damper 31. After that, as shown in FIG. 5, an adhesive is applied to the outer periphery of the shield cover 4 to
The voice coil spacer 45 is inserted into the center pole 1, the outer periphery of the lower damper 31 is placed on the outer periphery of the shield cover 4, and the inner periphery is placed on the outer periphery of the bobbin 8 of the voice coils 9a to 9c, and they are bonded together. Next, the sandwich block described with reference to FIGS. 2 and 3, that is, the magnetic circuit in which the three plates 32, 33 and 34, the drive magnet 6 and the cancel magnet 5 are integrally bonded and fixed. The block is attached to the shield cover 4 assembled in the state shown in FIG.

FIG. 6 is a view for explaining a state in which the drive magnet 6, the cancel magnet 5 and the like are attached to the shield cover 4. Reference numerals in the drawing are the same as those in FIGS. 1 and 5, and 46 is a second voice coil spacer, 46a.
Indicates a hole.

As shown in FIG. 6, in the shield cover 4 assembled up to the state shown in FIG. 5, the second voice coil spacer 46 is put on the outside of the bobbin 8 around which the voice coils 9a to 9c are wound. The first voice coil spacer 45 is pushed until it hits the tip. In this state, an adhesive is applied to the outer periphery near the bottom surface of the shield cover 4, the outer diameter of the second voice coil spacer 46 is inserted into the inner diameters of the three plates 32, 33, 34, and the bottom surface side is covered. The lower surface plate 32 is pushed until it hits the shield cover 4, and the adhesive is dried. Through the above steps, as shown in FIG. 1, the shield cover 4 has the center pole 1, the lower damper 31, and the voice coils 9a to 9a.
bobbin 8 around which c is wound, frame 10, and
A block in which the three plates 32, 33 and 34, the drive magnet 6 and the cancel magnet 5 are stacked in a sandwich shape is integrally assembled.

Finally, the upper damper 35, the edged cone paper 15, the tinsel thread 13 and the like are attached. After the adhesive has dried, pull out the second voice coil spacer 46,
As shown in FIG. 1, the outer periphery of the upper damper 35 is bonded to the outer periphery of the frame 10, and the inner periphery of the upper damper 35 is bonded to the outer diameter of the bobbin 8 around which the voice coils 9a to 9c are wound. At this time, the first voice coil spacer 45 remains inserted in the center pole 1.
In this case, the frame 10 is preferably attached to the upper surface plate 34 in advance by a method such as caulking. In this state, the outer periphery of the edge-attached cone paper 15 is the outer periphery of the frame 10, and the inner periphery of the cone paper 15 is the voice coil 9a.
9c are adhered to the outer diameter of the bobbin 8 around which the wound bobbin 8 is wound. After the adhesive has dried, insert the tinsel wire 13 into the input terminal 14
Solder to

Tin wire 37 on the detection coil 9 side for MFB
Similarly, it is also soldered to the MFB output terminal 36. Then, by removing the first voice coil spacer 45 from the center pole 1 and adhering the cap 12 to the top of the cone paper 15 or the tip of the bobbin 8, the speaker assembling process shown in FIG. 1 is completed. In the triple coil speaker completed in this way, as shown in FIG. 1, the upper damper 35 and the lower damper 31 are arranged vertically with the drive magnet 6 and the cancel magnet 5 sandwiched therebetween, and the triple coil speaker is used for rolling. Becomes very strong against
Further, since the two coils are connected in parallel, a large signal can be input. Therefore, a small speaker can emit a large sound. Moreover, by making the upper damper 35 and the lower damper 31 arranged vertically symmetrical with each other, the nonlinearity of the damper can be canceled and the distortion can be reduced.

As described above, in the triple coil speaker of the present invention, the three voice coils are provided (the invention of claim 1) and the dampers are arranged above and below (the invention of claim 5). It is possible to provide a speaker with a large allowable input. Even in a small speaker, the resonance sharpness Q _{0 at the} lowest resonance frequency is small,
Moreover, the resonance sharpness Q ₀ , the bass characteristic, and the bass reproduction band can be varied by the MFB (inventions 7 and 8). Further, when it is attached to a small speaker box, there is also an advantage that the bass reproduction band can be expanded (the inventions of claims 1 to 8). Furthermore, if two or three voice coils are connected so that a reverse current flows through each coil,
Since the driving force of each coil or three coils is added to obtain a large driving force, it is possible to effectively use the energy of the magnetic circuit (the invention of claim 6). In addition, the gap for the MFB can be formed at the time of forming the driving magnetic circuit, which is very advantageous (the inventions of claims 1 to 8).

[0042]

According to the triple-coil speaker of the first aspect, three voice coils are provided, and one is provided at each of the center and both sides of the drive magnet and the cancel magnet.
The plates are arranged. Therefore, in the small speaker, the resonance sharpness Q ₀ at the lowest resonance frequency can be reduced. In addition, the effects of increasing the allowable input, downsizing the speaker box, and improving the sound quality can be obtained.

According to the triple coil speaker of claim 2,
The triple coil speaker according to claim 1, wherein the first voice coil, the second voice coil, and the third voice coil are arranged at positions facing the respective gaps formed by the center pole and the three plates. are doing. Therefore, in addition to the effect of the triple coil speaker according to the first aspect, the magnetic flux intensity in the gap of the magnetic circuit can be increased.

According to the triple coil speaker of claim 2,
The triple coil speaker according to claim 1, wherein the first voice coil, the second voice coil, and the third voice coil are arranged at positions facing the respective gaps formed by the center pole and the three plates. are doing. Therefore, in addition to the effect of the triple coil speaker according to the first aspect, the magnetic flux intensity in the gap of the magnetic circuit can be increased.

In the triple coil speaker of claim 3,
In the triple coil speaker according to claim 1, a shield cover is provided to cover the outer circumferences of the drive magnet and the cancel magnet. Therefore, similarly to the triple coil speaker according to the second aspect, the magnetic flux intensity in the gap of the magnetic circuit can be increased.

According to the invention of claim 4, in the triple coil speaker of claim 1, a damper is provided between the bobbin and the shield cover or between the bobbin and the frame or other cover. Therefore, in addition to the effect of the triple coil speaker of claim 1, it becomes very strong against rolling.

According to a fifth aspect of the present invention, the triple coil speaker of the first aspect is provided with dampers between the bobbin and the shield cover and between the bobbin and the frame and other covers, and each damper is provided with a drive magnet and a drive magnet. The cancel magnets are arranged symmetrically. Therefore, similarly to the triple coil speaker according to the fourth aspect, it becomes very strong against rolling and it is possible to reduce nonlinear distortion.

According to the invention of claim 6, among the three voice coils provided in the triple coil speaker of claim 1, the position closest to the opening side of the cone paper is the first voice coil and the central position is the second voice coil. The position farthest from the opening side of the voice coil and the cone paper is the third voice coil, and the direction of the current flowing through the first voice coil and the third voice coil is opposite to that flowing through the second voice coil. ing. Therefore, in addition to the effect of the triple coil speaker of claim 1, a large signal can be input.

In the invention of claim 7, the three voice coils provided in the triple coil speaker of claim 1 are arranged such that the position closest to the opening side of the cone paper is the first voice coil and the central position is the second voice coil. The voice coil, the farthest position from the opening side of the cone paper is the third voice coil, and the first voice coil and the second voice coil are connected in parallel. Therefore, in addition to the effect of the triple coil speaker of claim 1, since the two coils are connected in parallel,
A large signal can be input.

According to the eighth aspect of the invention, among the three voice coils provided in the triple coil speaker of the first aspect, the position closest to the opening side of the cone paper is the first voice coil, and the central position is the second voice coil. The voice coil, the farthest position from the opening side of the cone paper is the third voice coil, and the third voice coil is composed of a coil having a diameter smaller than that of the first voice coil and the second voice coil. It is used as a voltage detection coil. Therefore, in addition to the effect of the triple coil speaker of claim 1, a small speaker can be obtained.

[Brief description of drawings]

FIG. 1 shows a triple coil speaker of the present invention,
It is sectional drawing which shows an example of embodiment of the principal part structure.

FIG. 2 shows the triple coil speaker of the present invention shown in FIG. 1, in which a drive magnet 6 and three plates (3
2, 33, 34) and the cancel magnet 5 are connected to each other.

FIG. 3 is a diagram illustrating a method for assembling the drive magnet 6, the three plates (32, 33, 34) and the cancel magnet 5 shown in FIG.

FIG. 4 is a diagram illustrating a method of attaching the shield cover 4 and the center pole 1 shown in FIG.

FIG. 5 is a diagram illustrating a state in which a lower damper 31 and voice coils 9a to 9c are attached to a shield cover 4.

FIG. 6 is a diagram illustrating a state in which a drive magnet 6 and a cancel magnet 5 are attached to the shield cover 4.

FIG. 7 is a cross-sectional view showing an example of a main part configuration of a conventional magnetic shield type speaker.

FIG. 8 is a cross-sectional view showing an example of a main part configuration of a conventional MFB speaker.

[Explanation of symbols]

1 center pole, 2 magnet guide, 3 yoke, 4 shield cover, 5 cancel magnet,
6 drive magnet, 7 plate, 8 bobbin, 9
Voice coil, 9a to 9c voice coil, 10 frame, 11 damper, 12 cap, 13 tinsel wire, 14 input terminal, 15 cone paper, 31 lower damper, 32 lower surface plate, 33 middle plate, 34
Top plate, 35 upper damper

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H04R 9/04 104 H04R 9/04 104A

Claims (8)

[Claims] 1. A center pole set up in the central portion of a cone paper, a voice coil attached to a bobbin arranged concentrically with the center pole, a drive magnet, and a reverse of the drive magnet. A speaker provided with a cancel magnet magnetized in a polarity, comprising three voice coils and a total of three plates respectively arranged at the center and both sides of the drive magnet and the cancel magnet. A triple coil speaker. 2. The first voice coil, the second voice coil, and the third voice coil are arranged at positions facing the respective gaps formed by the center pole and the three plates. The triple coil speaker according to claim 1, wherein 3. The triple coil speaker according to claim 1, further comprising a shield cover that covers outer peripheries of the drive magnet and the cancel magnet. 4. The triple coil speaker according to claim 1, further comprising a damper provided between the bobbin and the shield cover, or between the bobbin and the frame or other cover. 5. A damper is provided between the bobbin and the shield cover, and between the bobbin and the frame or other cover, and the dampers are symmetrically arranged with the drive magnet and the cancel magnet interposed therebetween. The triple coil speaker according to claim 1, wherein. 6. The first voice coil, the second voice coil, and the third voice coil have a first voice coil at a position closest to the opening side of the cone paper, and a second voice coil at a central position. The farthest position from the opening side of the cone paper is the third voice coil, and the direction of the current flowing through the first voice coil and the third voice coil is opposite to the direction flowing through the second voice coil. The triple coil speaker according to claim 1, wherein 7. The first voice coil, the second voice coil, and the third voice coil have a first voice coil at a position closest to the opening side of the cone paper, and a second voice coil at a central position. The triple voice coil according to claim 1, wherein a position farthest from the opening side of the cone paper is a third voice coil, and the first voice coil and the second voice coil are connected in parallel. Coil speaker. 8. The first voice coil, the second voice coil, and the third voice coil have a first voice coil at a position closest to the opening side of the cone paper, and a second voice coil at a central position. The farthest position from the opening side of the cone paper is the third voice coil, and the third voice coil is the first voice coil.
2. The triple coil speaker according to claim 1, wherein the triple coil speaker is a voltage detecting coil for MFB, which is constituted by a voice coil having a diameter smaller than that of the voice coil and a second voice coil.