JP2010263363A - Loudspeaker device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent degradation of sound quality by reducing restriction in a reciprocal movement of a vibration system. <P>SOLUTION: A loudspeaker device 1 forms a magnetic circuit by fixing a magnet 11 to a case 2, a first voice coil 33 is wound around an outer periphery on a back side of a voice coil bobbin 31 of the vibration system 3, and a pair of vibration control members 34, 35 holding the first voice coil 33 is provided. A second voice coil 36 is wound around the outer periphery of a diaphragm 32 of the vibration system 3. Around the first and second voice coils 33, 36, magnetic flux concentration parts 18, 19 are formed, where magnetic fluids 21A, 21B are poured and held. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a speaker for audio reproduction. More specifically, the present invention relates to a dynamic type speaker using an eddy fluid and having an edgeless / damperless structure.

  As a speaker for audio reproduction, a dynamic speaker is known that reproduces audio by passing a current through a voice coil arranged in a magnetic flux concentrating portion and vibrating a diaphragm. This type of dynamic speaker has a structure in which a diaphragm and a voice coil bobbin are supported by an edge and a damper.

Here, the damper has a role of supporting the vibration system including the diaphragm, the voice coil, and the voice coil bobbin so as to accurately reciprocate without contacting the magnetic circuit wall. Furthermore, the damper also plays a role of suppressing the inertia of the vibration system (braking / dumping) by matching the center of vibration of the voice coil with the center of the magnetic flux concentrating portion.
In addition, the edge has a role similar to that of the damper, and also has a role of blocking sound waves so that opposite-phase sound waves radiated to the front side and the back side of the diaphragm do not interfere with each other.

  The edge and the damper exist at different positions on the axis in the vibration direction. Therefore, the vibration system is supported at two points, and its movement is reliably controlled. As a result, the voice coil can reciprocate in a narrow magnetic flux concentrator without contacting the magnetic circuit wall.

  In order to play such a role, it is desirable that the damper and the edge have a stronger control force. On the other hand, in the original purpose of a speaker that faithfully converts an electric signal into a sound wave, the control power is hampered, leading to distortion of the reproduced sound. Furthermore, since the edges and the dampers themselves have natural vibrations, the vibrations of the edges and the dampers may cause unnecessary sound waves, that is, distortion, and make the reproduced sound muddy. Therefore, the conventional speaker is configured to inject the magnetic fluid into the magnetic flux concentrating portion at the position where the voice coil is arranged, and to support the vibration system via the magnetic fluid so as to suppress the distortion of the reproduced sound.

JP 2006-5852 A

However, since the conventional speaker has a configuration in which the edge is mechanically connected to the frame, the restriction in the reciprocating motion of the vibration system cannot be sufficiently reduced. For this reason, it has been desired to develop a speaker capable of removing distortion of reproduced sound and reproducing higher quality sound.
The present invention has been made in view of such circumstances, and it is a main object of the present invention to prevent deterioration in sound quality by reducing restrictions on the reciprocating motion of a vibration system.

According to one aspect of the present application, a magnetic circuit including a case made of a magnetic material and a magnet, a diaphragm that is reciprocally inserted into an opening on the front side of the case, A voice coil bobbin that is fixed to the center and inserted into the case, a first voice coil that is wound around the voice coil bobbin and receives an electrical signal, and wound around an outer periphery of the diaphragm, A second voice coil to which a signal is input; a pair of vibration control members made of a non-magnetic material, sandwiching the first voice coil in the direction in which the diaphragm moves; the magnet and the case; The first voice coil, the first magnetic fluid in which a part of the vibration control member is immersed, and the magnet are inserted into the first magnetic flux concentrating portion formed between Formed into Is injected into the second magnetic flux concentration region, the speakers second voice coil, characterized in that it comprises a second magnetic fluid to be immersed is provided.

  According to another aspect of the present invention, in the speaker according to claim 1, the magnet is housed in a recess of the case, and the first magnet into which the voice coil bobbin can be inserted; It has a 2nd magnet arrange | positioned facing the said 1st magnet on the back side, and the said 1st magnet and the 2nd magnet are arrange | positioned so that the same magnetic pole may face each other. A speaker is provided.

  Further, according to another aspect of the present invention, in the speaker according to claim 1 or 2, the pair of vibration control members is a first vibration control disposed on a back side of the first voice coil. A second vibration control member disposed on the front side of the member and the first voice coil, wherein a part of the front side of the first vibration control member is inserted into the first magnetic fluid, A speaker is provided in which a part of the back side of the second vibration control member is inserted into the first magnetic fluid.

  According to the present invention, the vibration system is supported by the magnetic fluid on each of the front side and the back side of the speaker. Furthermore, the vibration system can be driven by voice coils provided on the front side and the back side of the vibration system. For these reasons, restrictions on the movement of the vibration system are reduced, and deterioration of the sound quality of the reproduced sound is prevented.

FIG. 1 is a cross-sectional view showing a configuration of a speaker according to an embodiment of the present invention. FIG. 2 is an enlarged view of a part of FIG. 1 and shows a configuration around the first magnetic flux concentrating portion. FIG. 3 is an enlarged view of a part of FIG. 1 and shows a configuration around the second magnetic flux concentrating portion.

The best mode for carrying out the invention will be described in detail with reference to the drawings. In the following description, the side on which high-temperature sound is output is referred to as the front surface, and the opposite side is referred to as the back surface.
FIG. 1 shows a cross-sectional view of the speaker according to the present embodiment. The speaker 1 has a case 2, and a vibration system 3 is supported in the case 2 so as to be able to vibrate. Case 2 is manufactured from a magnetic material such as iron and functions as a yoke. A substantially circular opening 4 is formed in the front surface 2 </ b> A of the case 2.

  As shown in FIGS. 1 and 2, a pole piece 10 projects from the center of the case 2. The pole piece 10 extends in parallel with the axis m1, has a circular outer shape, and is provided with a tip portion 10A having a diameter increased at an end portion on the front surface side. Here, the axis m <b> 1 is a virtual line parallel to the vibration direction of the vibration system 3. The pole piece 10 is formed integrally with the case 2, but the pole piece 10 may be formed separately and fixed to the case 2. Further, in the case 2, a plurality of holes 5 are formed on the circumference centered on the pole piece 10 at regular intervals, for example. These holes 5 are used for venting air and passing cables.

  Further, a first magnet 12 is attached in the case 2. The first magnet 12 has a ring shape in which a through hole parallel to the axis m1 is formed. A predetermined gap is formed between the inner surface of the first magnet 12 and the tip portion 10 </ b> A of the pole piece 10. Further, the second magnet 14 is attached to the back surface 2 </ b> C of the case 2, and the yoke 15 of the second magnet 14 is attached. The 2nd magnet 14 is arrange | positioned so that case 2 may be pinched | interposed with the 1st magnet 12, and, thereby, the magnetic flux of the magnetic circuit formed with the 1st magnet 12 is strengthened. The yoke 15 is made of a magnetic material such as iron, and the front surface in contact with the second magnet 14 is flat, but the opposite side is hemispherical. By increasing the surface area of the back surface of the yoke 5 in this way, the magnetic flux is prevented from being concentrated on the back surface side.

  As the first and second magnets 12 and 14, permanent magnets, for example, magnets using neodymium having a high magnetic flux density and a very strong magnetic force are used. The speaker 1 may use only the first magnet 12 without providing the second magnet 14. The second magnet 14 is attached to the outside of the case 2, but may be accommodated in the case 2.

  In this embodiment, the first magnet 12 is fixed so that the N pole is arranged on the back side and the S pole is arranged on the front side. Further, the second magnet 14 is arranged so that the front side has the same polarity as the back side of the first magnet 12. That is, in this embodiment, the front surface of the second magnet 14 is an N pole, and the back surface is an S pole.

A frame 17 is attached in close contact with the front surface of the first magnet 12. The frame 17 is made of a magnetic material, has a shape that does not hinder the insertion and reciprocation of the vibration system 3, specifically a ring shape, and has an inner diameter that extends from the front side to the back side. It has a taper that gradually decreases. The inner diameter on the back side is larger than the outer diameter of the tip portion 10 </ b> A of the pole piece 10. The gap formed between the tip portion 10A of the pole piece 10 and the frame 17 becomes the first magnetic flux concentration portion 18 where the magnetic flux formed by the magnets 11 and 14 is concentrated.
Further, the outer diameter of the front end portion of the frame 17 is smaller than the inner diameter of the opening 4 of the case 2. A gap formed between the distal end portion of the frame 17 and the opening 4 of the case 2 becomes a second magnetic flux concentration portion 19 where the magnetic flux formed by the magnets 11 and 14 is concentrated. The frame 17 is formed with a plurality of holes 20 for venting air and passing cables. These holes penetrate the frame 17 obliquely so as to avoid the first magnet 12.

  The vibration system 3 includes a voice coil bobbin 31 that is detachably inserted into the case 2 and a diaphragm 32 that is attached to the front end portion of the voice coil bobbin 31.

The voice coil bobbin 31 is manufactured from a non-magnetic material and has a cylindrical shape. The outer diameter is smaller than the inner diameter of the frame 17 and larger than the outer diameter of the tip portion 10 </ b> A of the pole piece 10. A first voice coil 33 is wound around the outer periphery of the back end of the boil coil bobbin 31. The first voice coil 33 is formed by winding a conducting wire around the outer periphery of the boil coil bobbin 31 without a gap. The conducting wire of the first voice coil 33 is electrically connected to an amplifier (not shown). Further, a pair of vibration control members 34 and 35 are attached to the outer periphery of the boil coil bobbin 31 so as to sandwich the first voice coil 33. Each vibration control member 34, 35 is made of a nonmagnetic material, and is in close contact with the first boil coil 33 so that there is no gap between the first boil coil 33 in the axial direction. The outer diameters of the pair of vibration control members 34 and 45 are larger than the outer diameter of the first boil coil 33 and smaller than the inner diameter of the recess 2B of the case 2. For this reason, as shown in FIG. 2, there is a step at the boundary between the vibration control members 34 and 45 and the first voice coil 33. In FIG. 2, the first voice coil 3
3 has a configuration in which the conducting wire is wound in a single layer, but the conducting wire may be wound in a double layer or more.

  Here, a magnetic fluid 21A (first magnetic fluid) is injected and held in the first magnetic flux concentrating portion 18. The magnetic fluid 21A is injected in such an amount that the entire first boil coil 33 and a part of the pair of vibration control members 34 and 35 can be immersed. Specifically, the first vibration control member 34 is disposed on the back side of the first voice coil 33, and a part of the front side thereof is in the first direction d1, that is, from the back 2C side of the case 2 to the front 2A. The magnetic fluid 21A is inserted toward the side. The second vibration control member 35 is disposed on the front side of the first voice coil 33, and a part of the back side thereof is magnetic in the second direction d2, that is, from the front 2A side to the back 2C side of the case 2. It is inserted in the fluid 21A. As a result, the speaker 1 has the north pole of the first magnet 11, the case 2, the magnetic pole 21 </ b> A from the tip 10 </ b> A of the pole piece 10, and the south pole of the first magnet 11 from the frame 17. A first magnetic circuit returning to is formed.

  Further, as shown in FIGS. 1 and 3, the diaphragm 3 is fixed to the front side end of the boil coil bobbin 31. The diaphragm 32 is fixed to the central portion of the voice coil bobbin 31 and is made of a nonmagnetic material. The diaphragm 32 has a cone shape whose diameter increases toward the front surface with the axis m1 as the center, and the central opening is formed on the front surface. It is closed by a dome-shaped center cap 32A that protrudes toward the front. Further, the outer end 32B of the diaphragm 32 is folded back toward the back. The end 32B extends in parallel to the axis m1, and at least partly overlaps the inner peripheral surface of the opening 4 of the case 2 in the axial direction. More specifically, the end portion 32 </ b> B of the diaphragm 32 is disposed so as to penetrate the second magnetic flux concentration portion 19.

  Further, a second voice coil 36 is wound around the outer periphery of the end portion 32B. The second voice coil 36 is formed by winding a conducting wire around the outer periphery of the end portion 32B without a gap. The conducting wire of the second voice coil 36 is electrically connected to an amplifier (not shown). The length of the second voice coil 36 in the axial direction is such that the second voice coil 36 does not move out of the second magnetic flux concentrating portion 19 even when the vibration system 3 reciprocates. The winding directions of the voice coils 33 and 36 are managed so that both move in the same direction according to the input signal.

  A magnetic fluid 21B (second magnetic fluid) is injected and held in the second magnetic flux concentrating portion 19 between the diaphragm 32 and the case 2. The entire second voice coil 36 is immersed in the magnetic fluid 21B. Thus, a second magnetic circuit is formed from the north pole of the first magnet 12 to the case 2, the magnetic fluid 21 </ b> B, and the frame 17 to the south pole of the second magnet 14.

  The voice coil bobbin 31, the vibration control members 34 and 35, and the diaphragm 33 are desirably manufactured from materials that are inert, insoluble, and non-swellable with respect to the magnetic fluids 21A and 21B and do not have permeability. That is, metal impregnated with aluminum, magnesium, titanium, etc., polypropylene, polyethylene, PET, polyimide, fluororesin resin, paper, non-woven fabric, glass fiber, carbon fiber, aramid fiber, etc. impregnated or coated with resin Etc. are used.

Next, the operation of this embodiment will be described.
When the speaker 1 is connected to an amplifier (not shown) to generate sound such as sound or voice, the conductors of the first voice coil 33 and the second voice coil 36 are connected to the amplifier. At this time, the conducting wires of the two voice coils 33 and 36 can be connected to the amplifier in parallel or in series.

At the time of sound reproduction, an electric signal from the amplifier is input to each of the voice coils 33 and 36. The same electrical signal is input to each of the voice coils 33 and 36. When an electric signal flows through each of the two voice coils 31 and 36 disposed in the magnetic circuit, a force is generated by electromagnetic induction. Since the pole piece 10 and the frame 17 are integrally or fixed to the case 2, the first voice coil 33 mainly works to move the voice coil bobbin 31, and the second voice coil 36 mainly moves the diaphragm 32. Work to move. Since the two voice coils 33 and 36 are connected to the amplifier so as to generate forces in the same direction at substantially the same time, the entire vibration system 3 is moved in the first direction d1 or the second direction along the axis m1 by the input of the electric signal. It moves in the direction d2. Then, the movement amount and the movement direction of the vibration system 3 change with the change of the electric signal, so that vibration is generated, and as a result, sound is output from the diaphragm 32.

  At this time, since the vibration system 3 is supported by the case 2 via the magnetic fluids 21A and 21B on the distal end side of the diaphragm 32 and the proximal end side of the voice coil bobbin 31, the vibration system 3 moves forward and backward smoothly. be able to. That is, since the diaphragm 32 can accurately reciprocate in the vibration direction without contacting the magnetic circuit wall, distortion of reproduced sound is suppressed. In particular, since the voice coils 33 and 36 are arranged on the front side, that is, the end portion 32B of the diaphragm 32, and on the back side, that is, the base end of the voice coil 31, the driving by electromagnetic induction is performed smoothly. As a result, high quality sound is reproduced.

  Here, the speaker 1 is provided with vibration control members 34 and 35 so as to sandwich both ends of the first voice coil 33 in the advancing and retreating direction of the vibration system 3. As shown in FIG. 3, a part of each vibration control member 34, 35, specifically, a part on the front side of the first vibration control member 34 is immersed in the magnetic fluid 21 </ b> A, and the second vibration control member A part of the back side of 35 is immersed in the magnetic fluid 21A. As described above, since the outer diameters of the vibration control members 34 and 35 are larger than the outer diameter of the first voice coil 33, the area crossing the magnetic flux in the first magnetic flux concentrating portion 18 is larger than that of the first voice coil 33. The vibration control members 34 and 35 are larger. For this reason, the rejection force generated by the vibration control members 34 and 35 crossing the magnetic flux is larger than the rejection force generated by the voice coil 33.

For this reason, when the vibration system 3 moves in the second direction d2, and the second vibration control member 35 enters the magnetic fluid 21A by the same amount as the movement amount of the vibration system 3, the displacement force is increased accordingly. Becomes larger. This exclusion force acts as a force for moving the vibration system 3 in the opposite direction to the second direction d2, that is, in the first direction d1. Since this force increases as the volume of the second vibration control member 35 entering the magnetic fluid 21A increases, the greater the amount of movement of the vibration system 3 in the second direction d2, the more the vibration system 3 moves to the original position. The power to return to is increased.
On the other hand, when the vibration system 3 moves in the first direction d1 and the first vibration control member 34 enters the magnetic fluid 21A by the same amount as the movement amount of the vibration system 3, the displacement force is correspondingly increased. growing. This exclusion force acts as a force for moving the vibration system 3 in the opposite direction to the first direction d1, that is, in the second direction d2. Similarly to the above, this force increases as the volume of the first vibration control member 34 entering the magnetic fluid 21A increases. Therefore, the greater the amount of movement of the vibration system 3 in the first direction d1, the greater the vibration system. The force to return 3 to the original position increases.

  In this way, the vibration system 3 always receives a force on the opposite side to the moving direction of the vibration system 3 from the magnetic circuit due to the presence of the pair of vibration control members 34 and 35, so that the vibration system 3 moves in one direction. It is prevented from overpassing and stable reciprocating motion is possible. Further, since the boil coils 33 and 36 and the pair of vibration control members 34 and 35 are arranged so that the balance point of the rejecting force becomes the initial position (specified position) of the vibration system, the amplitude of the voice coils 33 and 36 is increased. The center and the centers of the magnetic flux concentration portions 18 and 19 can be matched.

  Since the first magnetic flux concentrating portion 18 is filled with the magnetic fluid 21 </ b> A, reverse-phase sound waves generated on the back side of the diaphragm 32 are blocked.

  As a result, it is possible to reproduce sound without mechanically joining the edge portions of the vibration system or providing a damper as in the conventional case.

  Further, when the speaker 1 is assembled, the lead wire of the voice coil 33 is connected, and the vibration system 3 may be inserted into the magnetic flux concentrating portions 18 and 21. A speaker can be easily manufactured in a short time without the need for alignment and adhesion required when mechanically joining conventional edges or providing dampers, and jigs required for these operations. .

  In addition, you may comprise the speaker system by mounting the speaker 1 in a cabinet.

DESCRIPTION OF SYMBOLS 1 Speaker 2 Case 3 Vibration system 11 1st magnet 14 2nd magnet 18 1st magnetic flux concentration part 19 2nd magnetic flux concentration part 21A 1st magnetic fluid 21B 2nd magnetic fluid 31 Voice coil bobbin 32 Diaphragm 32B End 33 First voice coil 34 First vibration control member 35 Second vibration control member 36 Second voice coil

Claims (3)

A magnetic circuit including a case made of a magnetic material and a magnet, and
A diaphragm inserted into the opening on the front side of the case so as to be reciprocally movable;
A voice coil bobbin fixed to the center of the diaphragm and inserted into the case;
A first voice coil wound around the voice coil bobbin and receiving an electrical signal;
A second voice coil wound around the outer periphery of the diaphragm and receiving an electrical signal;
A pair of vibration control members made of a non-magnetic material and disposed across the first voice coil in a direction in which the diaphragm moves;
A first magnetic fluid that is injected into a first magnetic flux concentrator formed between the magnet and the case, and in which the first voice coil and a part of the vibration control member are immersed;
A second magnetic fluid that is injected by the magnet into a second magnetic flux concentrating portion formed on the front side of the case and in which the second voice coil is immersed;
The speaker characterized by including.   The pair of vibration control members are a first vibration control member disposed on the back side of the first voice coil and a second vibration control member disposed on the front side of the first voice coil. A part of the front side of the first vibration control member is inserted into the first magnetic fluid, and a part of the rear side of the second vibration control member is inserted into the first magnetic fluid. The speaker according to claim 1.   The magnet is housed in a recess of the case and includes a first magnet into which the voice coil bobbin can be inserted, and a second magnet disposed on the back side of the case so as to face the first magnet. The speaker according to claim 1, wherein the first magnet and the second magnet are arranged so that the same magnetic pole faces each other.

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