Speaker

Abstract

A speaker that drives one diaphragm with two magnetic circuit sections has a compact configuration that can drive the diaphragm efficiently. [Solution] The speaker (1) comprises a diaphragm (2), two magnetic circuit sections (3, 3), two voice coil bodies (4, 4) inserted into the magnetic gaps (G) of the two magnetic circuit sections (3, 3) and moving axially relative to a magnet (32) and a yoke section (31) within the magnetic gaps (G) to vibrate the diaphragm (2), and a frame section (5) supporting the yoke sections (31) of the two magnetic circuit sections (3, 3) and the diaphragm (2). The two magnetic circuit sections (3, 3) are positioned so that the magnetic field of one magnetic circuit section (3) affects the magnetic field of the other magnetic circuit section (3). The magnetization directions of the magnets (32, 32) in the two magnetic circuit sections (3, 3) are opposite to each other. The directions of current flowing through the two voice coil bodies (4, 4) are opposite to each other when viewed from the diaphragm (2).

Description

[Technical Field]

[0001] The present invention relates to a speaker in which one diaphragm is vibrated by two voice coil assemblies arranged relative to two magnetic circuits. [Background technology]

[0002] There is known a speaker in which two voice coil bodies, each driven by two magnetic circuits, are connected to one diaphragm. For example, Patent Document 1 discloses a speaker device having two magnetic circuits with magnetic gaps, two voice coil bodies inserted into the magnetic gaps, and a long, flat diaphragm connected to the two voice coil bodies. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-161950 Summary of the Invention [Problem to be solved by the invention]

[0004] A speaker with two magnetic circuits has a larger amount of magnetic flux that drives the diaphragm than a speaker with one magnetic circuit, improving drive efficiency. However, if the magnets in the two magnetic circuits are close to each other, the magnetic fluxes formed by the two magnetic circuits will interfere with each other, increasing leakage magnetic flux in each magnetic circuit. As a result, the drive efficiency of the diaphragm will decrease.

[0005] Therefore, in general, in order to suppress magnetic flux interference in a speaker having two magnetic circuits, it is necessary to space the two magnets apart, as in the speaker device disclosed in Patent Document 1. In this case, the dimensions of the speaker increase in the direction in which the two magnets are aligned, making it difficult to construct a compact speaker.

[0006] Therefore, in a speaker that drives one diaphragm with two magnetic circuits, a compact configuration that can drive the diaphragm efficiently has been desired.

[0007] An object of the present invention is to provide a speaker that drives one diaphragm with two magnetic circuits, which is compact and has a configuration that can drive the diaphragm efficiently. [Means for solving the problem]

[0008] A speaker according to one embodiment of the present invention includes a diaphragm, two magnetic circuit units each having a magnet, a yoke, and a magnetic gap formed between the magnet and the yoke, and positioned on the rear side of the diaphragm, two voice coil bodies each having one axial end connected to the rear side of the diaphragm and the other axial end inserted into the magnetic gap, and moving axially relative to the magnet and the yoke within the magnetic gap to vibrate the diaphragm, and a frame unit supporting the yoke and the diaphragm of the two magnetic circuit units. The two magnetic circuit units are positioned so that the magnetic field of one magnetic circuit unit affects the magnetic field of the other magnetic circuit unit. The magnetization directions of the magnets in the two magnetic circuit units are opposite to each other. The directions of current flowing through the two voice coil bodies are opposite to each other when viewed from the diaphragm (first configuration).

[0009] In the above-described configuration, the magnetization directions of the two magnets are opposite to each other, so interference between the magnetic fluxes of the two magnetic circuits can be prevented while the magnetic flux of one magnetic circuit unit can form a magnetic flux loop with the magnetic flux of the other magnetic circuit unit, thereby improving magnetic flux efficiency even when the yoke portions of the two magnetic circuits are close to each other.

[0010] Furthermore, because the currents flowing through the two voice coil bodies are in opposite directions as viewed from the diaphragm, the voice coil bodies move in the same direction, providing a configuration in which one diaphragm can be efficiently driven by two magnetic circuits.

[0011] Therefore, in a speaker in which one diaphragm is driven by two magnetic circuit portions, it is possible to provide a compact configuration that can drive the diaphragm efficiently.

[0012] In the first configuration, the shortest distance between the two yoke portions in the direction in which the magnets of the two magnetic circuit portions are arranged is shorter than the length of each magnet in the direction in which the magnets are arranged in the two magnetic circuit portions (second configuration).

[0013] This provides a configuration in which the magnetic flux of one of the two magnetic circuit units is induced to the other magnetic circuit unit, and the magnetic flux of the other magnetic circuit unit is induced to the one magnetic circuit unit, thereby providing a configuration in which the leakage magnetic flux of the one magnetic circuit unit can be easily captured by the other magnetic circuit unit, and the leakage magnetic flux of the other magnetic circuit unit can be easily captured by the one magnetic circuit unit.

[0014] In the first or second configuration, the yoke portion each has a cylindrical yoke main body portion with a bottom that opens toward the diaphragm, and a flange portion located at the open end of the yoke main body portion and extending outward when viewed in the axial direction (third configuration).

[0015] When the yoke portions of two magnetic circuit units come into contact with each other in a configuration in which their magnetic fields affect each other, if the contact area between the yoke portions is large, the magnetic flux distribution in each magnetic circuit unit may be disturbed, potentially reducing the magnetic flux efficiency.

[0016] In contrast, the above-described configuration allows the flange portions to contact each other but the yoke main bodies not to contact each other. This prevents the contact area between the yoke portions from increasing. This prevents the magnetic flux distribution in each magnetic circuit from becoming distorted. This prevents a decrease in the magnetic flux efficiency in each magnetic circuit.

[0017] In the third configuration, the frame portion supports the portions of the outer surfaces of the yoke main bodies of the two magnetic circuit portions that face each other in the alignment direction, and supports the portions of the flange portions of the two magnetic circuit portions that are adjacent to each other in the alignment direction in the axial direction (fourth configuration).

[0018] If two magnetic circuit sections are positioned so that the magnetic field of one magnetic circuit section influences the magnetic field of the other magnetic circuit section, the magnets of the two magnetic circuit sections will attract each other, making it difficult to fix the two yoke sections in place.

[0019] In contrast, in the above-described configuration, the frame supports the two yoke bodies so that they are spaced apart in the alignment direction, while supporting the flanges of the yoke bodies in the axial direction, which makes it easy to fix the two yoke bodies at predetermined positions in the alignment direction and the axial direction.

[0020] Therefore, in a speaker having two magnetic circuit portions, it is possible to provide a configuration that allows the two magnets to be easily fixed in close positions to each other. [Effects of the Invention]

[0021] The speaker of the present invention has two magnetic circuit sections positioned so that the magnetic field of one magnetic circuit section influences the magnetic field of the other magnetic circuit section. The magnetization directions of the magnets in the two magnetic circuit sections are opposite to each other, and the directions of currents flowing through the coils of the two voice coil bodies are opposite to each other when viewed from the diaphragm.

[0022] This allows a magnetic flux loop to be formed between one magnetic circuit unit and the other magnetic circuit unit while preventing interference between the magnetic fluxes of the two magnetic circuit units. Therefore, magnetic flux efficiency can be improved even if the yoke portions of the two magnetic circuit units are close to each other. Therefore, a speaker that drives one diaphragm with two magnetic circuit units can be provided with a compact configuration that can efficiently drive the diaphragm. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view showing an example of a schematic configuration of a speaker. [Figure 2] FIG. 2 is an exploded perspective view of the speaker. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a diagram schematically showing the flow of magnetic flux in two magnetic circuit portions. [Figure 5] FIG. 5 is a plan view of the two magnetic circuit units and the two voice coil bodies as viewed from the diaphragm. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and their description will not be repeated. Furthermore, the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components, the dimensional ratios of the components, etc.

[0025] In the following description, the axial direction of the voice coil body 4 will be referred to as the "axial direction," the arrangement direction of the two voice coil bodies 4 will be referred to as the "arrangement direction," and the direction perpendicular to the axial direction and the arrangement direction will be referred to as the "width direction."

[0026] Furthermore, in the following description, the expressions "fix," "connect," and "attach" (hereinafter referred to as "fixing") include not only cases where members are directly fixed to each other, but also cases where members are fixed via other members. In other words, in the following description, the expression "fixing" includes both direct and indirect fixing of members to each other.

[0027] (Overall composition) FIG. 1 is a perspective view showing an example of the schematic configuration of speaker 1. FIG. 2 is an exploded perspective view of speaker 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. As shown in FIGS. 1 to 3, speaker 1 has a diaphragm 2 that is flat. Speaker 1 is mounted in, for example, a thin electrical device.

[0028] The speaker 1 has a diaphragm 2, two magnetic circuit units 3, two voice coil bodies 4, a frame unit 5, an edge unit 6, and a terminal board 7. In the speaker 1, the yoke units 31 of the two magnetic circuit units 3 are close to each other. In this specification, "the yoke units 31 are close to each other" means that the shortest distance between the yoke units 31 in the arrangement direction of the magnets 32 located within the yoke unit 31 is shorter than the length of the magnets 32 in the arrangement direction.

[0029] The diaphragm 2 is a member that converts vibrations into sound waves. The diaphragm 2 is made of, for example, synthetic resin, honeycomb metal, etc. In this embodiment, the diaphragm 2 has a rectangular shape when viewed in the thickness direction.

[0030] Two voice coil bodies 4, 4 are connected to the rear surface of the diaphragm 2. The two voice coil bodies 4, 4 are each moved in the axial direction by the magnetic field of the magnetic circuit unit 3. The axial movement of the two voice coil bodies 4, 4 causes the diaphragm 2 to vibrate in the axial direction.

[0031] An edge portion 6 is connected to the outer periphery of the diaphragm 2. The diaphragm 2 is attached to the frame portion 5 via the edge portion 6. In other words, the diaphragm 2 is supported by the frame portion 5.

[0032] As shown in FIGS. 2 and 3, the two magnetic circuit units 3, 3 are located on the rear side of the diaphragm 2. The two magnetic circuit units 3, 3 form magnetic fields that are independent of each other, and each moves one voice coil body 4, 4 in the axial direction. The two magnetic circuit units 3, 3 have the same configuration except that the magnetization directions of the magnets 32 are opposite to each other. Therefore, the following describes the configuration of one magnetic circuit unit 3. The configurations of the two magnetic circuit units 3, 3 and the magnetic fields of the two magnetic circuit units 3, 3 will be described later.

[0033] The magnetic circuit unit 3 includes a yoke unit 31, a magnet 32, a plate 33, and a magnetic gap G.

[0034] The yoke portion 31 is made of a magnetic material. Together with the plate 33, the yoke portion 31 forms a magnetic path for the magnetic flux generated by the magnet 32. The yoke portion 31 is located on the rear surface side of the diaphragm 2 and is supported by the frame portion 5. Details of the support structure of the yoke portion 31 by the frame portion 5 will be described later.

[0035] In this embodiment, the yoke portion 31 has a cylindrical yoke main body portion 311 with a bottom that opens toward the diaphragm 2, and a flange portion 312 that is located at the open end of the yoke main body portion 311 and extends outward when viewed in the axial direction.

[0036] Magnet 32 ​​and plate 33 are positioned in this order toward one side of the axial direction within yoke main body 311. The end face of magnet 32 ​​on the other side of the axial direction is in contact with the bottom surface of yoke main body 311. Yoke 31 is magnetized to have the same polarity as the end face of magnet 32 ​​with which it is in contact.

[0037] The magnet 32 ​​has a north pole on one side or the other in the axial direction and a south pole on the opposite side. The magnet 32 ​​is a ferrite magnet, a neodymium magnet, a samarium-cobalt magnet, an alnico magnet, etc. The type of magnet 32 ​​is not particularly limited.

[0038] The axial length of magnet 32 ​​is shorter than the depth of yoke main body 311. Therefore, when positioned within yoke main body 311, one axial side of magnet 32 ​​is located on the other axial side of the end of yoke main body 311 on the opening side. Note that the depth of yoke main body 311 is the axial length from the end face of yoke main body 311 on the axial opening side to the bottom surface of yoke main body 311. Plate 33 is stacked on one axial end face of magnet 32.

[0039] A gap is formed around the entire circumference between the outer periphery of magnet 32 ​​and the inner periphery of yoke main body 311 .

[0040] The plate 33 is made of a magnetic material and forms a magnetic path for the magnetic flux generated by the magnet 32 ​​together with the yoke portion 31.

[0041] Plate 33 is plate-shaped and is stacked on one axial side of magnet 32. The surface on one axial side of plate 33 and the end face on one axial side of yoke main body 311 are located at the same height in the axial direction. Plate 33 is magnetized to have the same polarity as the end face of magnet 32 ​​with which it is in contact. In other words, plate 33 has a polarity opposite to that of yoke portion 31.

[0042] Plate 33 has the same shape as one axial end face of magnet 32 ​​when viewed in the thickness direction. Therefore, a gap is formed around the entire circumference between the outer circumferential surface of plate 33 and the inner circumferential surface of yoke main body 311. This gap constitutes magnetic gap G. Voice coil body 4 is inserted into magnetic gap G.

[0043] In the magnetic circuit unit 3 configured as described above, a magnetic circuit is formed by the magnet 32, the yoke portion 31, and the plate 33. The magnetic flux flowing in the magnetic circuit passes through the magnetic gap G. That is, the magnetic flux flowing in the magnetic circuit passes through the voice coil body 4 inserted in the magnetic gap G. This causes the voice coil body 4 to move in the axial direction.

[0044] As shown in FIG. 2, in this embodiment, the yoke body 311 is cylindrical with a bottom, the magnet 32 ​​is columnar, and the plate 33 is disk-shaped. However, the yoke body and the magnet may have any shape as long as a predetermined gap is formed between the inner peripheral surface of the yoke body and the outer peripheral surface of the magnet over the entire circumference. The plate may have the same shape as the end of one side of the magnet in the axial direction. For example, the yoke body, magnet, and plate may have an elliptical or rectangular shape when viewed in the axial direction.

[0045] The two voice coil bodies 4, 4 vibrate the diaphragm 2. Each of the two voice coil bodies 4, 4 has a cylindrical shape extending in the axial direction. Each voice coil body 4 has a cylindrical bobbin and a coil formed by winding a conductive wire around the bobbin. One axial end of the voice coil body 4 is connected to the rear surface of the diaphragm 2. The other axial end of the voice coil body 4 is inserted into the magnetic gap G so as to be movable in the axial direction relative to the yoke portion 31 and the magnet 32.

[0046] Lead wires 41 of the conductor forming the voice coil body 4 are connected in parallel to a terminal board 7. A sound source (not shown) is connected to the terminal board 7. An electric signal from the sound source is sent to the voice coil body 4 via the terminal board 7. This electric signal flows through the voice coil body as a current. The voice coil body 4 moves axially within the magnetic gap G due to the magnetic field of the magnetic circuit section 3. This causes the diaphragm 2 to vibrate.

[0047] The frame portion 5 supports the two yoke portions 31 of the two magnetic circuit portions 3, the diaphragm 2, and the terminal plate 7. As shown in Figures 2 and 3, the frame portion 5 has a first frame portion 51 located on the other side in the axial direction, and a second frame portion 52 located on one side in the axial direction.

[0048] The frame portion 5 has a rectangular shape with one length longer than the other when viewed in the axial direction. The frame portion 5 is large enough to support a maximum of one magnetic circuit portion 3 in its short side direction and a maximum of two magnetic circuit portions 3 in its long side direction. That is, the length of the frame portion 5 in the short side direction is less than twice the maximum length of the yoke portion 31 in the short side direction. The length of the frame portion 5 in the long side direction is less than three times the maximum length of the yoke portion 31 in the long side direction.

[0049] The first frame portion 51 is made of a non-magnetic material and has a bottom wall 511 located at the other end in the axial direction, and a side wall 512 extending in the axial direction from the outer periphery of the bottom wall 511. That is, the first frame portion 51 has an internal storage space for storing the two magnetic circuit portions 3, 3.

[0050] Two through holes 51a, 51a are provided in the bottom wall 511 of the first frame portion 51. As shown in Fig. 3, the yoke portions 31 of the magnetic circuit portion 3 are inserted into and fixed to the two through holes 51a, 51a, respectively. A terminal plate 7 is attached to the other side of the first frame portion 51 in the axial direction.

[0051] 3, the two through holes 51a, 51a are inserted into the two yoke sections 31, 31 at the other axial side of the flanges 312 of the yoke main sections 311. In this embodiment, when inserted into the through hole 51a, the outer circumferential surface of the yoke main section 311 contacts the inner circumferential surface of the through hole 51a. In addition, the flanges 312 contact the portion of the bottom wall 511 that is located around the through hole 51a when viewed in the axial direction.

[0052] The second frame portion 52 is located on one side of the first frame portion 51 in the axial direction. The second frame portion 52 extends in an annular shape along the end face of the first frame portion 51 on the opening 51b side. That is, the second frame portion 52 has a rectangular frame shape and has a rectangular opening 52a. The diaphragm 2 is attached to the second frame portion 52 via an edge portion 6 so as to be located inside the opening 52a when viewed in the axial direction.

[0053] The edge portion 6 is located between the inner periphery of the second frame portion 52 and the outer periphery of the diaphragm 2, and supports the diaphragm 2 so that it can be displaced in the axial direction relative to the frame portion 5. The edge portion 6 is made of a flexible material, such as foam rubber. The edge portion 6 functions to return the diaphragm 2, which has been driven by the voice coil body 4 and displaced in the axial direction, to its original position.

[0054] (Configuration of two magnetic circuit parts and magnetic field) Next, the magnetic field generated by the two magnetic circuit sections 3 of the speaker 1 will be described with reference to Figures 4 and 5. Figure 4 is a diagram schematically showing the flow of magnetic flux in the two magnetic circuit sections 3, 3 of the speaker 1. Figure 5 is a plan view of the two magnetic circuit sections 3, 3 and the two voice coil bodies 4, 4 as viewed from the diaphragm 2. In Figure 4, the flow of magnetic flux is indicated by dashed arrows. Furthermore, the direction in which the voice coil body 4 moves when a current flows is indicated by a hollow arrow. In Figure 5, the direction of current flowing in the coil is indicated by a solid arrow.

[0055] As described above, the two magnetic circuit portions 3, 3 of the speaker 1 form magnetic fields that are independent of each other. That is, in the speaker 1, the first magnetic circuit portion 3a, which is one of the two magnetic circuit portions 3, 3, forms one magnetic field, and the second magnetic circuit portion 3b, which is the other, forms another magnetic field. Also, in the speaker 1, the yoke portions 31, 31 of the two magnetic circuit portions 3, 3 are close to each other. Therefore, in the speaker 1, the magnetic field of the first magnetic circuit portion 3a affects the magnetic field of the second magnetic circuit portion 3b.

[0056] In the speaker 1, the magnetization direction of the magnet 32 ​​of the first magnetic circuit portion 3a and the magnetization direction of the magnet 32 ​​of the second magnetic circuit portion 3b are opposite to each other. For example, the magnet 32 ​​of the first magnetic circuit portion 3a has a north pole on one side in the axial direction and a south pole on the other side. The magnet 32 ​​of the second magnetic circuit portion 3b has a south pole on one side in the axial direction and a north pole on the other side.

[0057] Therefore, in the speaker 1, the magnetic flux of the first magnetic circuit portion 3a and the magnetic flux of the second magnetic circuit portion 3b do not interfere with each other. That is, the magnetic flux of the first magnetic circuit portion 3a can flow toward the second magnetic circuit portion 3b. Therefore, leakage magnetic flux is reduced in the first magnetic circuit portion 3a. Furthermore, the magnetic flux of the second magnetic circuit portion 3b can flow toward the first magnetic circuit portion 3a. Therefore, leakage magnetic flux is reduced in the second magnetic circuit portion 3b.

[0058] Furthermore, by arranging the two magnets 32 in this manner, leakage magnetic flux generated in the first magnetic circuit portion 3a can be induced to the second magnetic circuit portion 3b, and leakage magnetic flux generated in the second magnetic circuit portion 3b can be induced to the first magnetic circuit portion 3a. This reduces the overall amount of leakage magnetic flux, thereby increasing the amount of effective magnetic flux. This makes it possible to achieve a compact configuration with improved magnetic flux efficiency.

[0059] 5, in the speaker 1, the directions of current flowing through the two voice coil bodies 4, 4 are opposite to each other when viewed from the diaphragm 2. For example, the direction of current flowing through the first voice coil body 4a, which is disposed within the magnetic gap G of the first magnetic circuit portion 3a, is clockwise when viewed from the diaphragm 2. The direction of current flowing through the second voice coil body 4b, which is disposed within the magnetic gap G of the second magnetic circuit portion 3b, is counterclockwise when viewed from the diaphragm 2.

[0060] As a result, when a current flows through the first voice coil body 4a, the first voice coil body 4a moves to one side in the axial direction. When a current flows through the second voice coil body 4b, the second voice coil body 4b moves to one side in the axial direction. In other words, the first voice coil body 4a and the second voice coil body 4b are driven in the same direction. Therefore, one diaphragm 2 can be driven efficiently by two magnetic circuit units 3, 3.

[0061] Therefore, in the speaker 1 in which one diaphragm 2 is driven by two magnetic circuit portions 3, 3, it is possible to provide a compact configuration that can drive the diaphragm 2 efficiently.

[0062] (Support structure for two yoke sections by the frame section) Next, the support structure of the two yoke portions 31, 31 by the frame portion 5 will be described with reference to FIGS.

[0063] As described above, the first frame portion 51 has two through holes 51a in the bottom wall 511, into which the two yoke main bodies 311 are respectively inserted. The other axial side of the yoke main body 311 is inserted into each through hole 51a. The two flange portions 312 are located on one axial side of the two through holes 51a. The outer circumferential surface of the yoke main body 311 contacts the inner circumferential surface of each through hole 51a. The other axial surfaces of the two flange portions 312 contact the surface on one axial side of the bottom wall 511 of the first frame portion 51.

[0064] As a result, the two yoke portions 31, 31 are positioned at predetermined positions relative to the first frame portion 51 in the arrangement direction, width direction, and axial direction.

[0065] In this embodiment, when the two yoke portions 31 are inserted into the two through-holes 51a, respectively, the flange portions 312 of the two yoke portions 31 are in contact with each other, and therefore the two yoke main bodies 311 are spaced apart from each other.

[0066] When the yoke portions of two magnetic circuit units come into contact with each other in a configuration in which their magnetic fields affect each other, if the contact area between the yoke portions is large, the magnetic flux distribution in each magnetic circuit unit may be disturbed, potentially reducing the magnetic flux efficiency.

[0067] In contrast, in the above-described configuration, the flange portions 312, 312 are in contact with each other, but the yoke main bodies 311, 311 are not in contact with each other. This prevents the contact area between the yoke portions 31, 31 from increasing. This prevents the magnetic flux distribution in each of the two magnetic circuit portions 3, 3 from becoming distorted. This prevents a decrease in the magnetic flux efficiency in each magnetic circuit portion 3.

[0068] A portion of the bottom wall 511 of the first frame portion 51 is located between the opposing portions of the two yoke main bodies 311 in the arrangement direction of the two yoke portions 31. A portion of the bottom wall 511 of the first frame portion 51 is in axial contact with portions of the two flange portions 312 that are adjacent in the arrangement direction.

[0069] When the magnets 32, 32 of the two magnetic circuit parts 3, 3 are located close to each other and have opposite magnetization directions, as in the speaker 1, the two magnets 32, 32 attract each other, making it difficult to fix the two yoke parts 31, 31 in the predetermined positions.

[0070] In contrast, the portion of the bottom wall 511 of the first frame portion 51 supports the two yoke main bodies 311, 311 so as to separate them in the arrangement direction, while supporting the flange portion 312 of the yoke portion 31 in the axial direction. This makes it possible to easily fix the two yoke portions 31, 31 at predetermined positions in the arrangement direction and the axial direction.

[0071] Therefore, in the speaker 1 in which one diaphragm 2 is driven by two magnetic circuit portions 3, 3, it is possible to provide a compact and easily fixable configuration.

[0072] The exemplary speaker 1 described above includes a diaphragm 2, two magnetic circuit units 3, 3 located on the rear side of the diaphragm 2, each having a magnet 32, a yoke 31, and a magnetic gap G formed between the magnet 32 ​​and the yoke 31, two voice coil bodies 4, 4 each having one axial end connected to the rear side of the diaphragm 2 and the other axial end inserted into the magnetic gap G, and moving axially within the magnetic gap G relative to the magnet 32 ​​and yoke 31 to vibrate the diaphragm 2, and a frame 5 supporting the yoke 31 of the two magnetic circuit units 3, 3 and the diaphragm 2. The two magnetic circuit units 3, 3 are positioned so that the magnetic field of one magnetic circuit unit 3 affects the magnetic field of the other magnetic circuit unit 3. The magnetization directions of the magnets 32 in the two magnetic circuit units 3, 3 are opposite to each other. The directions of current flowing through the two voice coil bodies 4, 4 are opposite to each other when viewed from the diaphragm 2.

[0073] In a speaker with two magnetic circuit units, the amount of magnetic flux that drives the diaphragm is greater than in a speaker with one magnetic circuit unit, and this improves the efficiency of driving the diaphragm. However, if the magnetization directions of the magnets in the two magnetic circuit units are the same and the yoke units of the two magnetic circuit units are close to each other and their magnetic fields affect each other, the magnetic fluxes of the two magnetic circuit units will interfere with each other, increasing leakage flux and reducing magnetic flux efficiency.

[0074] In the above-described configuration, the magnetization directions of the two magnets 32 are opposite to each other, so interference between the magnetic fluxes of the two magnetic circuit units 3 is prevented, and a magnetic flux loop can be formed by the magnetic flux of one magnetic circuit unit 3 and the magnetic flux of the other magnetic circuit unit 3. Therefore, even if the yoke units 31 of the two magnetic circuit units 3 are close to each other, the magnetic flux efficiency can be improved.

[0075] Furthermore, because the directions of the currents flowing through the two voice coil bodies 4, 4 are opposite to each other when viewed from the diaphragm 2, the voice coil bodies 4, 4 move in the same direction. This provides a configuration in which one diaphragm 2 can be efficiently driven by two magnetic circuit sections 3, 3.

[0076] Therefore, in the speaker 1 in which one diaphragm 2 is driven by two magnetic circuit portions 3, 3, it is possible to provide a compact configuration that can drive the diaphragm 2 efficiently.

[0077] In addition, in this embodiment, each yoke portion 31 has a cylindrical yoke main body portion 311 with a bottom that opens toward the diaphragm 2, and a flange portion 312 that is located at the open end of the yoke main body portion 311 and extends outward when viewed in the axial direction.

[0078] When the yoke portions of two magnetic circuit units come into contact with each other in a configuration in which their magnetic fields affect each other, if the contact area between the yoke portions is large, the magnetic flux distribution in each magnetic circuit unit may be disturbed, potentially reducing the magnetic flux efficiency.

[0079] In contrast, the above-described configuration allows the flange portions 312, 312 to be in contact with each other, but the yoke main bodies 311, 311 to be prevented from contacting each other. This prevents the contact area between the yoke portions 31, 31 from increasing. This prevents the magnetic flux distribution in each magnetic circuit portion 3 from being disturbed. This prevents the magnetic flux efficiency in each magnetic circuit portion 3 from decreasing.

[0080] In addition, in this embodiment, the frame portion 5 supports, in the alignment direction, the portions of the outer surfaces of the yoke main bodies 311 of the two magnetic circuit portions 3, 3 that face each other in the alignment direction of the yoke main bodies 311, 311, and also supports, in the axial direction, the portions of the flange portions 312 of the two magnetic circuit portions 3, 3 that are adjacent to each other in the alignment direction.

[0081] When two magnetic circuit sections 3, 3 are positioned so that the magnetic field of one magnetic circuit section 3 affects the magnetic field of the other magnetic circuit section 3, the magnets 32, 32 of the two magnetic circuit sections 3, 3 are attracted to each other. This makes it difficult to fix the two yoke sections 31, 31 in a predetermined position. In contrast, in the above-described configuration, the frame section 5 supports the two yoke main sections 311, 311 so that they are spaced apart in the alignment direction, while supporting the flange section 312 of the yoke section 31 in the axial direction. This makes it easy to fix the two yoke sections 31, 31 in a predetermined position in the alignment direction and the axial direction.

[0082] Therefore, in the speaker 1 having the two magnetic circuit portions 3, 3, it is possible to provide a configuration that allows the two magnets 32, 32 to be easily fixed in close positions to each other.

[0083] (Other embodiments) Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiments, and it is possible to appropriately modify the above-described embodiments within the scope of the spirit of the present invention.

[0084] In the above embodiment, the flange portions 312, 312 of the yoke portions 31 of the two magnetic circuit units 3, 3 are in contact with each other. That is, the two yoke portions 31, 31 are in contact with each other. However, the two yoke portions need only be located in positions where the magnetic field of one of the two magnetic circuit units affects the magnetic field of the other magnetic circuit unit. For example, the shortest distance between the two yoke portions in the arrangement direction of the magnets of the two magnetic circuit units may be shorter than the length of each magnet in the arrangement direction of the two magnetic circuit units.

[0085] This provides a configuration in which the magnetic flux of one of the two magnetic circuit units is induced to the other magnetic circuit unit, and the magnetic flux of the other magnetic circuit unit is induced to the one magnetic circuit unit, thereby providing a configuration in which the leakage magnetic flux of the one magnetic circuit unit can be easily captured by the other magnetic circuit unit, and the leakage magnetic flux of the other magnetic circuit unit can be easily captured by the one magnetic circuit unit.

[0086] In the above embodiment, the flange portions 312, 312 of the yoke portions 31 of the two magnetic circuit portions 3, 3 are in contact with each other. However, the flange portions do not have to be in contact with each other. There may be a small gap between the flange portions at the portion where the two flange portions are closest to each other. For example, there may be a gap between the flange portions that is smaller than the thickness of the yoke main body.

[0087] In the above embodiment, the magnetic circuit unit 3 includes a plate 33. However, the magnetic circuit unit does not have to include a plate. That is, the plate does not have to be stacked on one side of the magnet in the axial direction. In this case, it is preferable that the axial length of the magnet is equal to the depth of the yoke main body. Note that in order to reduce leakage magnetic flux and improve magnetic efficiency, it is preferable that the plate be located on one side of the magnet in the axial direction.

[0088] In the above embodiment, the yoke portion 31 has a flange portion 312. However, the yoke portion does not have to have a flange portion. However, in order to position the yoke portion relative to the frame portion, it is preferable that the yoke portion has a flange portion.

[0089] In the above embodiment, the two yoke portions 31, 31 of the two magnetic circuit portions 3, 3 are inserted into the two through holes 51 a, 51 a of the first frame portion 51, thereby being positioned at predetermined positions in the alignment direction, width direction, and axial direction relative to the frame portion 5. However, the two yoke portions may be positioned at predetermined positions relative to the frame portion by other methods. For example, the two yoke portions may be positioned at predetermined positions by being supported by multiple protrusions protruding from the bottom wall of the first frame portion to one side in the axial direction.

[0090] The frame preferably has a portion that supports, in the axial direction, portions of the outer circumferential surfaces of the yoke main bodies of the two magnetic circuit units that face each other in the arranging direction of the yoke main bodies.The frame preferably also has a portion that supports, in the axial direction, portions of the flanges of the two magnetic circuit units that are adjacent in the arranging direction. [Industrial Applicability]

[0091] The present invention can be used in a speaker in which one diaphragm is vibrated by two voice coil assemblies arranged relative to two magnetic circuit portions. [Explanation of symbols]

[0092] 1 speaker 2 diaphragm 3 Magnetic circuit section 3a First magnetic circuit section 3b Second magnetic circuit section 4 Voice coil body 4a First voice coil body 4b Second voice coil body 5 Frame section 6 Edge 7 Terminal board 31 York 32 Magnet 33 Plate 41 Lead Line 51 First frame section 51a Through hole 51b aperture 52 Second frame section 52a aperture 311 Yoke body 312 Flange 511 Bottom wall 512 Side wall G Magnetic gap

Claims

1. A vibration plate; two magnetic circuit units each having a magnet, a cylindrical yoke unit that houses the magnet, a plate stacked on the magnet, and a magnetic gap formed between the plate and the yoke unit, the two magnetic circuit units being located on the back side of the single diaphragm; two voice coil bodies, each having one axial end connected to a rear surface of the one diaphragm and the other axial end inserted into the magnetic gap, which move in the axial direction relative to the magnet and the yoke portion within the magnetic gap, thereby vibrating the one diaphragm; a frame portion that supports the yoke portions of the two magnetic circuit portions and the one diaphragm; A speaker having The two magnetic circuit portions are positioned so that the magnetic field of one magnetic circuit portion influences the magnetic field of the other magnetic circuit portion, the magnetization directions of the magnets in the two magnetic circuit portions are opposite to each other; The directions of currents flowing through the two voice coil bodies are opposite to each other when viewed from the single diaphragm. Speaker.

2. 2. The speaker according to claim 1, the shortest distance between the two yoke portions in the direction in which the magnets of the two magnetic circuit portions are arranged is shorter than the length of each magnet in the two magnetic circuit portions in the direction in which the magnets are arranged; Speaker.

3. 3. The speaker according to claim 1, The yoke portions each include: a cylindrical yoke body having a bottom and an opening facing the single diaphragm; a flange portion located at an open end of the yoke body and extending outward as viewed in the axial direction; and, having Speaker.

4. 4. The speaker according to claim 3, the frame portion supports, in the arranging direction, portions of the outer circumferential surfaces of the yoke main bodies of the two magnetic circuit units that face each other in the arranging direction of the yoke main bodies, and supports, in the axial direction, portions of the flange portions of the two magnetic circuit units that are adjacent to each other in the arranging direction. Speaker.

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