JP2015115711A - Speaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speaker that achieves both improvement in output of a low sound range and stable holding of a vibration system.SOLUTION: An outer peripheral shape of a magnetic circuit that includes an inner magnet 103, an outer magnet 104, an inner magnetic pole 105, a bottom plate 106, and an outer magnetic pole 107 is a substantially rectangular shape four corners of which have circular arc shapes. Each of the inner magnet 103, the inner magnetic pole 105, and the bottom plate 106 has a through hole at the center. Both of the inner magnet 103 and the outer magnet 104 are magnetized in a perpendicular direction, and the directions thereof are opposite to each other. Each of the outer peripheral shape and the inner peripheral shape of the outer magnet 104 and the outer magnetic pole 107 are a doughnut shape four corners of which have circular arc shapes. One of the corners is in contact with a position-holding magnetic fluid 114b of the outer magnetic pole 107. A vibration body includes a vibration plate 109, an extension part 110b, and a voice coil. Supporting means includes suspensions 112a and 112b, a sealing magnetic fluid 113, and the position-holding magnetic fluid 114b.

Description

  The present invention relates to an improvement in operational stability of a speaker that is small and capable of high-output reproduction with low sound.

  In recent years, with the spread of tablet terminals and smartphones, there is an increasing demand for playing high-quality content on these mobile devices. As a method of realizing the space saving required for these mobile devices and capable of reproducing a low sound range, a method of an electrodynamic speaker disclosed in Patent Document 1 has been proposed.

Japanese Patent Application No. 2009-542463

  However, in the loudspeaker disclosed in Patent Document 1, the function of the support for holding the diaphragm is weak, and further study is necessary for improving the output in the low sound range. In addition, contact between the voice coil and other components was not taken into consideration when the influence of external force due to falling or shaking was taken into consideration.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a speaker that achieves both improved output in the low sound range and stable maintenance of the vibration system.

A frame, a magnetic circuit fixed to the frame, a vibrating body arranged to vibrate in a predetermined direction, a first supporting means for supporting the vibrating body, and a second supporting means for supporting the vibrating body A speaker comprising:
Magnetic circuit
A first magnet magnetized in a direction orthogonal to the vibration direction;
A second magnet that is magnetized in a direction orthogonal to the vibration direction and is arranged outside the first magnet;
A first magnetic pole fixed to the first parallel surface of the first magnet;
A second magnetic pole fixed to the second parallel surface of the second magnet,
The vibrating body is
A voice coil disposed in a gap between the first magnetic pole and the second magnetic pole;
A diaphragm fixed to the voice coil and arranged with a space from the first magnetic pole,
An extension part connected to a part of the outer periphery of the diaphragm and extending in the vertical direction from the outside of the second magnetic pole,
The first support means acoustically blocks the space above and below the diaphragm separated by the diaphragm,
The second support means is provided between the extension portion and the second magnetic pole, and holds the vibrating body at a predetermined position.

  According to the present invention, it is possible to provide a speaker that achieves both stable operation and high-output reproduction in a low sound range.

Top view of speaker 100 according to Embodiment 1 of the present invention. 1A is a cross-sectional view taken along the line 1A-1A 'of FIG. 1, and FIG. 1B is a cross-sectional view taken along the line 1B-1B' of FIG. Sectional drawing in 1C-1C 'of Fig.2 (a) Top view of speaker 200 according to Embodiment 2 of the present invention. 4A is a cross-sectional view taken along 2A-2A 'in FIG. 4, FIG. 4B is a cross-sectional view taken along 2B-2B' in FIG. 4, and FIG. 4C is a cross-sectional view taken along 2C-2C 'in FIG. Sectional drawing in 2D-2D 'of Fig.5 (a) Top view of speaker 300 according to Embodiment 3 of the present invention. 7A is a cross-sectional view taken along 3A-3A 'in FIG. 7, and FIG. 8B is a cross-sectional view taken along 3B-3B' in FIG. Cross-sectional view of the structure of the speaker disclosed in Patent Document 1

(Knowledge that became the basis of the present invention)
FIG. 9 is a structural cross-sectional view of the speaker 1100 disclosed in Patent Document 1. As shown in FIG. 9A is a top view of the speaker 1100. FIG. FIG. 9B is a cross-sectional view of the structure of the speaker 1100 when the speaker 1100 is cut along the line AOB shown in FIG. As shown in FIG. 9, a speaker 1100 of Patent Document 1 includes a yoke 1101, a magnet 1102, a plate 1103, a diaphragm 1106, edge pieces 1108a to 1108d, a spacer 1109, a voice coil 1107, and a magnetic fluid. 1110. The magnetic fluid 1110 is filled on the inner peripheral side of the voice coil 1107 in the magnetic gap G2. According to the disclosure of Patent Document 1, the support body that supports the vibration plate 1106 so as to vibrate is composed of a plurality of edge pieces 1108a to 1108d. Therefore, even if the speaker 1100 is downsized, the stiffness of the support body is reduced. It is possible to operate with a large amplitude. Further, since the magnetic fluid 1110 is filled on the inner peripheral side of the voice coil 1107 in the magnetic gap G2, sound waves radiated from the back surface of the diaphragm 13 leak to the front surface of the diaphragm 13 via the magnetic gap G2. The sound pressure emitted from the front surface of the diaphragm 1106 can be prevented and the sound pressure can be improved.

  However, when an attempt is made to improve the low-frequency output of the conventional speaker 1100, the support is weak in holding the diaphragm 1106 and the voice coil 1107 within the vibration range, which hinders stable operation of the diaphragm 1106. Can be done. The amplitude of the diaphragm necessary to obtain the same sound pressure increases as the frequency decreases. However, when the diaphragm 1106 is operated at a large amplitude, only the edge pieces 1108a to 1108d support the diaphragm 1106. Therefore, the voice coil 1107 can easily come into contact with the yoke 1101 and the plate 1103 when an external force in a direction different from the vibration direction is applied due to dropping or shaking. Further, when the magnetic gap G2 is reduced in order to improve the magnetic flux density in the magnetic gap in which the voice coil 1107 is arranged, the distance between the voice coil 1107 and the yoke 1101 or the plate 1103 is narrowed. The risk of contact with 1101 and the plate 1103 is further increased.

  In order to solve the above-described problems, a speaker according to the present invention includes a frame, a magnetic circuit fixed to the frame, a vibrating body arranged to vibrate in a predetermined direction, and a first supporting the vibrating body. A speaker comprising support means and second support means for supporting a vibrating body, wherein the magnetic circuit has a first magnet magnetized in a direction orthogonal to the vibration direction, and a vibration direction. A second magnet magnetized in an orthogonal direction and disposed outside the first magnet; a first magnetic pole fixed to the first parallel surface of the first magnet; and a second magnet second The vibrating body includes a voice coil disposed in a gap between the first magnetic pole and the second magnetic pole, and a voice coil fixed to the voice coil so as to separate the space from the first magnetic pole. And a part of the outer periphery of the diaphragm The first support means acoustically blocks a space above and below the diaphragm separated by the diaphragm, and the second support means includes: It is provided between the extension part and the second magnetic pole, and is characterized in that the vibrating body is held at a predetermined position.

  According to this configuration, since the vibrating body is held within the vibration range by the second support means, the speaker can be stably operated while improving the output in the low sound range.

  In the speaker of the present invention, the first support means and the second support means may be a magnetic fluid.

  According to this configuration, since the increase in the stiffness of the support system due to the provision of the second support means is very small, the vibrating body can be held within the vibration range without reducing the bass reproduction capability.

  In the speaker of the present invention, the extension portions may be provided at a plurality of locations on the outer periphery of the diaphragm, and the second support means may be provided at a plurality of regions corresponding to the plurality of extension portions.

  According to this configuration, since the second support means can be disposed only at a position that is highly effective for holding the vibrating body, the vibrating body is held within the vibration range without increasing the size of the entire speaker. be able to.

  In the speaker of the present invention, the third parallel surface facing the first parallel surface of the first magnet and the fourth parallel surface facing the second parallel surface of the second magnet are connected. A bottom plate may be further provided.

  In the speaker of the present invention, the first support means is a magnetic fluid and may be provided either between the voice coil and the first magnetic pole or between the voice coil and the second magnetic pole.

  According to this configuration, the two spaces separated by the diaphragm can be cut off acoustically without increasing the stiffness of the vibration system.

  The speaker of the present invention may further include third support means for supporting the vibrating body, and the third support means may connect the diaphragm and the frame at a plurality of locations.

  According to this configuration, the stability of the operation of the speaker can be further improved by holding the vibrating body within the vibration range by both the second support means and the third support means.

  In the speaker of the present invention, the first support means may be a flexible material, and may be disposed over the entire circumference of the diaphragm to connect the diaphragm and the frame.

  According to this configuration, it is possible to achieve both cost reduction and stable maintenance of the vibration system by blocking the space facing the diaphragm with the edge material of a normal speaker.

  In the speaker of the present invention, the extension of the vibrating body may be integrally formed with the diaphragm.

  According to this configuration, since the function of holding the vibrating body can be realized without separately providing a member, it is possible to achieve both cost reduction and stable holding of the vibration system.

  Further, the magnetic circuit may have a substantially rectangular shape having curved portions at four corners when viewed from above, and the second support means may be provided outside either the curved portion or the short side portion of the magnetic circuit.

  According to this configuration, since the second support means is provided at the four corners and the short sides which are empty spaces in the speaker, the vibrating body can be held within the vibration range without increasing the size of the entire speaker. .

  In the speaker of the present invention, the magnetic circuit has a track shape having two substantially straight portions facing each other and two arc portions facing each other in a top view, and the second support means is an arc portion of the magnetic circuit. It may be provided outside.

  According to this configuration, since the second support means is provided in the arc portion which is an empty space in the speaker, the vibrating body can be held within the vibration range without increasing the width of the speaker.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Note that each of the embodiments described below shows a specific example of the present invention. Numerical values, shapes, components, steps, order of steps and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements. In all the embodiments, the contents can be combined.

(Embodiment 1)
With reference to FIGS. 1-3, the structure of the speaker 100 which concerns on Embodiment 1 of this invention is demonstrated.

  1 is a top view of the speaker 100, FIG. 2 (a) is a cross-sectional view taken along the line 1A-1A ′ of FIG. 1, and FIG. 2 (b) is a cross-sectional view taken along the line 1B-1B ′ of FIG. FIG. 3 is a cross-sectional view taken along the line 1C-1C ′ of FIG.

  In the first embodiment, the top view shape of the speaker 100 is rectangular. The speaker 100 includes a frame 101, a magnetic circuit 102, a vibrating body 108, and a support unit 111.

  The magnetic circuit 102 includes an inner magnet 103, an outer magnet 104, an inner magnetic pole 105, a bottom plate 106, and an outer magnetic pole 107. The outer peripheral shape of the magnetic circuit 102 in a top view is a substantially rectangular shape with arcs at the four corners. The inner magnet 103, the inner magnetic pole 105, and the bottom plate 106 each have a through hole at the center. The inner magnet 103 and the outer magnet 104 are both magnetized in the vertical direction of FIG. 2A, and their directions are opposite to each other in FIG. The outer magnet 104 and the outer magnetic pole 107 each have a so-called donut shape in which the outer periphery and the inner periphery are arc-shaped at the four corners. As shown in FIG. 3B, grooves are provided on both sides of each of the four locations where the outer magnetic pole 107 is in contact with the position-retaining magnetic fluids 114a to 114d.

  The vibrating body 108 includes a diaphragm 109, extensions 110 a to 110 d, and a voice coil 115. The top view shape of the diaphragm 109 is a substantially rectangular shape with four corners having an arc shape like the magnetic circuit 102. The extension portions 110a to 110d are continuous (connected) to the arc portions at the four corners of the diaphragm 109, and extend vertically downward from the outside of the arc portion of the outer magnetic pole 107 (corresponding to A in FIG. 2B). Where to do). The material of the extension portions 110a to 110d is the same material as that of the diaphragm 109. For example, the extension sections 110a to 110d may be integrally formed at the same time as the diaphragm 109 is molded. The voice coil 115 is disposed in the gap between the inner periphery of the outer magnetic pole 107 and the outer periphery of the inner magnetic pole 105 so as to be able to vibrate up and down, and the top view shape is a substantially rectangular shape with arc-shaped four corners according to the shape of the vibration plate 109. . The voice coil 115 further includes two lead lines (not shown).

  The support means 111 includes suspensions 112a and 112b, a sealing magnetic fluid 113, and position holding magnetic fluids 114a to 114d. The suspensions 112 a and 112 b have an arc shape whose section is convex upward, one end of the arc of the section is connected to the inner periphery of the frame 101, and the other end is connected to the inner side of the short side of the diaphragm 109. The sealing magnetic fluid 113 is filled in an annular shape over the entire circumference of the gap between the voice coil 115 and the inner magnetic pole 105, and blocks the air above and below the diaphragm 109. The position maintaining magnetic fluids 114 a to 114 d are filled in gaps between the extension portions 110 a to 110 d and the four corners of the outer magnetic pole 107, respectively.

  The operation of the speaker 100 configured as described above will be described. When an electrical signal is input to the voice coil 115, the voice coil 115 vibrates according to Fleming's left-hand rule. Since the diaphragm 109 is joined to the voice coil 115, the diaphragm 109 vibrates with the vibration of the voice coil 115, causes a pressure change in the air on the upper surface and the lower surface, and emits a sound wave. The sealing magnetic fluid 113 is annularly filled over the entire circumference of the gap between the voice coil 115 and the inner magnetic pole 105 and is generated on the upper and lower surfaces of the diaphragm 109 by being held by a magnetic field generated by the magnetic circuit 102. The sound waves having opposite phases to each other are blocked to prevent the reproduction sound pressure from being lowered due to the wraparound of the sound waves.

  The magnetic fluids 114 a to 114 d for holding the position are held on the outer peripheral side of the outer magnetic pole 107 by a magnetic field generated by a leakage magnetic flux outside the magnetic circuit 102 among the magnetic fields generated by the magnetic circuit 102. The inner wall of the portion (A in FIG. 2 (b)) extending vertically downward from the extension portions 110a to 110d is outside like the position holding magnetic fluids 114a to 114d due to the adhesive force of the position holding magnetic fluids 114a to 114d. It is held on the outer peripheral side of the magnetic pole 107. Thereby, even if the vibrating body 108 is displaced in a direction different from the axis X which is the vibration direction by an external force or an inertial force, and the positions of the extending portions 110a to 110d are shifted, the extending portions 110a to 110d are moved to the outer peripheral side of the outer magnetic pole 107. Since the force for returning to the working force acts, the vibrating body 108 can be held in the original vibration range.

  Further, the ease of displacement of the vibrating body 108 in a direction different from the axis X is determined by the moment around the center of gravity Y of the vibrating body 108. The action of holding the body 108 in the vibration range is great. Here, since the magnetic fluids 114a to 114d for holding the position hold the extension portions 110a to 110d on the outer peripheral side of the outer magnetic pole 107, the position holding magnetic fluids 114a to 114d are positioned near the voice coil 115 (for example, the gap between the voice coil 115 and the outer magnetic pole 107). The vibrating body 108 can be held more effectively than in the case where the extension portions 110a to 110d are held.

  Therefore, according to the speaker 100 according to Embodiment 1 of the present invention, the position holding magnetic fluids 114a to 114d stably hold the position of the vibrating body 108 in the vibration range, so that the voice coil 115 and the inner magnetic pole 105, or The contact between the voice coil 115 and the outer magnetic pole 107 can be prevented, and the speaker 100 can be stably operated while obtaining the vibration amplitude necessary for the output in the low sound range. In addition, since the minimum width of the magnetic gap in which the voice coil 115 and the inner magnetic pole 105 or the voice coil 115 and the outer magnetic pole 107 do not contact with each other can be reduced, the magnetic field passing through the voice coil 115 is further increased and the speaker 100 is highly efficient. be able to.

  Further, grooves are provided on both sides of each of the four portions in contact with the magnetic fluids 114a to 114d for holding the position of the outer magnetic pole 107 as shown in FIG. As a result, the contact angle between the position holding magnetic fluids 114a to 114d and the side surface of the outer magnetic pole 107 in the groove portion is increased as compared with the case where there is no groove portion. Is prevented, and the position-retaining magnetic fluids 114 a to 114 d can be prevented from moving to other positions of the outer magnetic pole 107. Further, as shown in FIG. 2B, the arc portion on the outer periphery of the outer magnetic pole 107 protrudes from the arc portion on the outer periphery of the outer magnet 104. It is possible to prevent movement to other positions.

  In the speaker 100 according to the first embodiment of the present invention, the horizontal portions of the diaphragm 109 and the extension portions 110a to 110d are formed in a flat plate shape, but a structure may be provided in which bending rigidity is increased by providing a rib for each. Moreover, it is good also as a structure which raises bending rigidity by combining several flat plate-shaped material. With these configurations, the vibration body 108 can be prevented from being deformed in directions other than the vibration direction, and the vibration plate 109 and the extension portions 110a to 110d can be vibrated as a unit.

  Further, in the speaker 100, the outer magnetic pole 107 has a flat plate shape, but the outer peripheral portion may extend vertically downward, and the cross-sectional shape of the end portion may have an L shape. With this configuration, the contact area between the outer peripheral portion of the outer magnetic pole 107 and the position holding magnetic fluids 114a to 114d can be increased, and the holding effect by the position holding magnetic fluids 114a to 114d can be enhanced and at the same time the outer periphery of the outer magnetic pole 107 can be increased. The distance between the portion and the bottom plate 106 is reduced, and the magnetic field acting on the position-retaining magnetic fluids 114a to 114d can be increased.

  Further, in the speaker 100, grooves are provided on the outer periphery of the outer magnetic pole 107 as a means for preventing the position holding magnetic fluids 114a to 114d from moving to other positions of the outer magnetic pole 107 (FIG. 3B). For example, an oil repellent may be applied to a portion of the outer periphery of the outer magnetic pole 107 that does not come into contact with the position-retaining magnetic fluids 114a to 114d or on the upper surface side. Further, the surface roughness of the outer periphery of the outer magnetic pole 107 that does not come into contact with the surface that comes into contact with the position holding magnetic fluids 114a to 114d may be reduced. Furthermore, these means may be used in combination.

  Moreover, in the speaker 100, you may give the process which improves lipophilicity to the inner side surface of extension part 110a-110d. Further, the surface of the outer periphery of the outer magnetic pole 107 that comes into contact with the position-retaining magnetic fluids 114a to 114d may be processed to increase the lipophilicity. These processes can be realized by adding a lipophilic material separately or by increasing the surface roughness of the original member.

  Further, in the speaker 100, the outer magnet 104 is provided separately from the inner magnet 103. However, the speaker 100 does not include the outer magnet 104, the outer periphery of the bottom plate 106 is extended in a box shape, and the extended side surface is the outer magnetic pole. You may use as 107. At this time, a downward movement of the position holding magnetic fluids 114a to 114d may be prevented by providing a groove at a predetermined height below a region in contact with the position holding magnetic fluids 114a to 114d of the outer magnetic pole 107.

  Further, in the speaker 100, the sealing magnetic fluid 113 is filled between the voice coil 115 and the inner magnetic pole 105. However, the position holding magnetic fluids 114a to 114d are filled in the entire outer periphery of the outer magnetic pole 107 and sealed. It may also serve as the magnetic fluid 113 for use. According to this configuration, the area contributing to the generation of sound waves of the vibrating body 208 can be increased by setting the sealing position to the outside, and the efficiency of the speaker 100 can be further improved.

  In the speaker 100, the voice coil 115 is directly fixed to the diaphragm 109 and is in direct contact with the sealing magnetic fluid 113. However, the voice coil 115 is separately wound around the outer periphery of the cylindrical voice coil bobbin. The voice coil may be configured not to directly contact either the diaphragm 109 or the sealing magnetic fluid 113.

  In the speaker 100, the sealing magnetic fluid 113 blocks the air above and below the diaphragm 109, and the suspensions 112a and 112b are divided into a plurality of parts. A configuration may be adopted in which the magnetic fluid 113 is not provided and one suspension is disposed over the entire circumference of the diaphragm 109 to connect the diaphragm 109 and the frame 101. In this configuration, the suspension material is desirably a flexible material that does not hinder the operation of the diaphragm 109.

(Embodiment 2)
The structure of the speaker 200 according to Embodiment 2 of the present invention will be described with reference to FIGS. 4 is a top view of the speaker 200, FIG. 5 (a) is a cross-sectional view taken along 2A-2A ′ in FIG. 4, and FIG. 5 (b) is a cross-sectional view taken along 2B-2B ′ in FIG. FIG. 5C is a cross-sectional view taken along 2C-2C ′ in FIG. FIG. 6 is a cross-sectional view taken along 2D-2D ′ in FIG.

  In the second embodiment, as in the first embodiment, the top view shape of the speaker 200 is a rectangle. The speaker 200 includes a frame 201, a magnetic circuit 202, a vibrating body 208, and support means 211.

  The magnetic circuit 202 includes an inner magnet 203, rod-shaped outer magnets 204a to 204d, an inner magnetic pole 205, a bottom plate 206, and outer magnetic poles 207a to 207d. The top view shape of the magnetic circuit 202 is rectangular. The inner magnet 203, the inner magnetic pole 205, and the bottom plate 206 each have a through hole in the center. As in the first embodiment, the inner magnet 203 and the outer magnets 204a to 204d are magnetized in the opposite directions in the vertical direction of FIG.

  The vibration body 208 includes a vibration plate 209, extensions 210 a and 210 b, and a voice coil 215. The top view shape of the diaphragm 209 is a rectangle like the magnetic circuit 202.

  Unlike the first embodiment, the extension portions 210a and 210b are continuous with the short side of the diaphragm 109 and extend vertically downward from the outside of the outer magnetic poles 207b and 207d. The voice coil 215 is disposed in a gap between the inner side of the outer magnetic poles 207 a to 207 d and the outer periphery of the inner magnetic pole 105 so as to vibrate up and down, and the top view shape is a rectangle according to the shape of the diaphragm 209. The voice coil 215 further includes two lead wires (not shown).

  The support means 211 includes suspensions 212a to 212d provided inside the four corners of the vibration plate 209, a sealing magnetic fluid 213, and position holding magnetic fluids 214a and 214b. As shown in FIG. 5C, the suspensions 212 a to 212 d have a circular arc shape whose cross section is convex upward, and the ends of the circular arcs of the cross section are located on the inner circumference of the frame 201 and the inner side of the long side of the diaphragm 209. . As in the first embodiment, the sealing magnetic fluid 213 is annularly filled over the entire circumference of the gap between the voice coil 215 and the inner magnetic pole 205, and blocks the air above and below the diaphragm 209. ing. The magnetic fluids 214a and 214b for position holding are divided and filled in the gaps between the extensions 210a and 210b and the outer sides of the outer magnetic poles 207b and 207d, respectively.

  According to the speaker 200 according to the second embodiment of the present invention, as in the first embodiment, the position-maintaining magnetic fluids 214a and 214b stably hold the position of the vibrating body 208 in the vibration range, thereby outputting a low-frequency range. The speaker 200 can be stably operated while obtaining the vibration amplitude necessary for the operation. Further, by arranging the rod-like outer magnets 204a to 204d separately, the magnet can be easily molded and the material loss generated by the punching process can be reduced as compared with the case of using an annularly molded magnet. The member cost can be reduced.

(Embodiment 3)
The structure of speaker 300 according to Embodiment 3 of the present invention will be described with reference to FIGS. 7 is a top view of the speaker 300, FIG. 8A is a cross-sectional view taken along 3A-3A ′ in FIG. 7, and FIG. 8B is a cross-sectional view taken along 3B-3B ′ in FIG. It is.

  In the third embodiment, the top view shape of the speaker 300 is a rectangle elongated in the horizontal direction in the figure as compared with the speakers 100 and 200. The speaker 300 includes a frame 301, a magnetic circuit 302, a vibrating body 308, and support means 311.

  The magnetic circuit 302 includes an inner magnet 303, an inner magnetic pole 305, a yoke 306, and auxiliary magnets 307a and 307b. The top view of the magnetic circuit 302 is a rounded rectangle formed by connecting two semicircles with a straight line. The inner magnet 303, the inner magnetic pole 305, and the yoke 306 each have a through hole at the center. The inner magnet 203 is magnetized in the vertical direction of FIG. The auxiliary magnets 307a and 307b are magnetized radially in the direction perpendicular to the semicircular arc of the yoke 306 and parallel to the 3B-3B 'cross section of FIG.

  The vibrating body 308 includes a diaphragm 309, extensions 310 a and 310 b, and a voice coil 315. The top view shape of the diaphragm 309 is a rounded rectangle like the magnetic circuit 302.

  The extension portions 310a and 310b are continuous (connected) to the semicircular portion of the diaphragm 309 and extend vertically downward outside the auxiliary magnets 307a and 307b. The voice coil 315 is disposed so as to be able to vibrate up and down in the inner periphery of the yoke 306 and the gap between the auxiliary magnets 307a and 307b and the outer periphery of the inner magnetic pole 305, and the top view shape is a rounded rectangle conforming to the shape of the diaphragm 309. is there. The voice coil 315 further includes two lead wires (not shown).

  The support means 311 includes suspensions 312a, 3b provided on the semicircular portion of the vibration plate 309, a sealing magnetic fluid 313, and position holding magnetic fluids 314a, 314b. As shown in FIG. 8A, the suspensions 312 a and 3 b have an arc shape whose section is convex upward, and the ends of the arcs of the section are on the inner circumference of the frame 301 and the semicircular portion of the diaphragm 309. The sealing magnetic fluid 313 is filled in an annular shape over the entire circumference of the gap between the voice coil 315 and the inner magnetic pole 305 to block the air above and below the diaphragm 309. The position maintaining magnetic fluids 314a and 314b are divided and filled in the gaps between the extensions 310a and 310b and the outer sides of the auxiliary magnets 307a and 307b, respectively.

  According to the speaker 300 according to the third embodiment of the present invention, as in the first and second embodiments, the position-holding magnetic fluids 314a and 314b stably hold the position of the vibrating body 308 in the vibration range. The speaker 300 can be stably operated while obtaining the vibration amplitude necessary for the output of. Further, by arranging the auxiliary magnets 307a and 307b in the semicircular portion of the magnetic circuit 302, the magnet having a smaller volume contributes to the magnetic field that contributes to the operation of the voice coil 315 and the holding of the magnetic fluids 314a and 314b for holding the position. A magnetic field can be generated, and the cost of the magnet material can be suppressed.

  In the third embodiment of the present invention, the materials of the inner magnet 303 and the auxiliary magnets 307a and 307b are not particularly limited, but the same or different materials may be used from the viewpoint of cost and performance. For example, either a rare earth magnet or a ferrite magnet may be used as the material of the inner magnet 303, and either a ferrite magnet or a bonded magnet may be used as the material of the auxiliary magnets 307a and 307b. The magnetizing directions of the auxiliary magnets 307 a and b are radial in the direction perpendicular to the semicircular arc of the yoke 306, but may be magnetized in a linear direction in the long side direction of the speaker 300.

  The speaker according to the present invention can provide a small and thin speaker with improved reliability and bass reproduction capability. Inner ear headphones, portable information terminal, video / audio information terminal, hearing aid, headset, display device It can be used for other AV devices.

100, 200, 300, 1100 Speaker 101, 201, 301 Frame 102, 202, 302 Magnetic circuit 103, 203, 303 Inner magnet 104, 204a-d Outer magnet 105, 205, 305 Inner magnetic pole 106, 206 Bottom plate 107, 207a -D outer magnetic poles 108, 208, 308 vibrating bodies 109, 209, 309, 1106 diaphragms 110a-d, 210a, 210b, 310a, 310b extensions 111, 211, 311 support means 112a, 112b, 212a-d, 312a, 312b Suspension 113, 213, 313 Magnetic fluid for sealing
114a-d, 214a, 214b, 314a, 314b Magnetic fluid for holding 115, 215, 315, 1107 Voice coil 306 Yoke 307a, b Auxiliary magnet 1101 Yoke 1102 Magnet 1103 Plate 1108a-1108d Edge piece 1109 Spacer 1110 Magnetic fluid G2 Magnetic gap

Claims (10)

A frame, a magnetic circuit fixed to the frame, a vibrating body arranged to vibrate in a predetermined direction, a first supporting means for supporting the vibrating body, and a second supporting means for supporting the vibrating body A speaker comprising:
The magnetic circuit is:
A first magnet magnetized in a direction orthogonal to the vibration direction;
A second magnet magnetized in a direction perpendicular to the vibration direction and disposed outside the first magnet;
A first magnetic pole fixed to the first parallel surface of the first magnet;
A second magnetic pole fixed to the second parallel surface of the second magnet,
The vibrator is
A voice coil disposed in a gap between the first magnetic pole and the second magnetic pole;
A diaphragm fixed to the voice coil and disposed with a space from the first magnetic pole;
An extension part connected to a part of the outer periphery of the diaphragm and extending in the vertical direction from the outside of the second magnetic pole;
The first support means acoustically blocks a space above and below the diaphragm separated by the diaphragm,
The speaker is characterized in that the second support means is provided between the extension portion and the second magnetic pole, and holds the vibrating body at a predetermined position.   The speaker according to claim 1, wherein the first support means and the second support means are magnetic fluids. The extension is provided at a plurality of locations on the outer periphery of the diaphragm,
The speaker according to claim 1, wherein the second support means is provided in a plurality of regions corresponding to the plurality of extensions.   A bottom plate connected to the third parallel surface facing the first parallel surface of the first magnet and the fourth parallel surface facing the second parallel surface of the second magnet. The speaker according to claim 1, further comprising:   The first support means is a magnetic fluid, and is provided between the voice coil and the first magnetic pole or between the voice coil and the second magnetic pole. The speaker according to 1.   6. The apparatus according to claim 1, further comprising third support means for supporting the vibrating body, wherein the third support means connects the diaphragm and the frame at a plurality of locations. The speaker according to 1.   2. The speaker according to claim 1, wherein the first support means is made of a flexible material, is disposed over the entire circumference of the diaphragm, and connects the diaphragm and the frame. 3.   The speaker according to claim 1, wherein the extension portion of the vibrating body is integrally formed with the diaphragm.   The magnetic circuit has a substantially rectangular shape with curved portions at four corners when viewed from above, and the second support means is provided outside either the curved portion or the short side portion of the magnetic circuit. The speaker according to claim 1.   The magnetic circuit has a track shape having two substantially linear portions facing each other in top view and two arc portions facing each other, and the second support means is provided outside the arc portion of the magnetic circuit. The speaker according to claim 1, wherein:

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