Speaker

Abstract

The present invention provides a speaker with which the magnetic flux density of a second magnetic gap can easily be secured.　A magnetic circuit 40 included in the speaker 10 forms a first magnetic path 71 and a second magnetic path 72. The magnetic circuit 40 includes: a cylindrical magnetic member 43 that forms a section of the first magnetic path 71 between an outer formation surface G1b of a first magnetic gap G1 and an inner formation surface G2a of a second magnetic gap G2; and bypass magnetic path formation parts 41, 42, 45 that form a section of the first magnetic path 71 between an outer formation surface G2b of the second magnetic gap G2 and an inner formation surface G1a of the first magnetic gap G1. A first space 61 separating the cylindrical magnetic member 43 and the bypass magnetic path formation parts 41, 42, 45 in the radial direction is formed on the lower side of the first magnetic gap G1.

Description

Speaker

[0001] The present disclosure relates to a speaker.

[0002] The speaker disclosed in Patent Document 1 includes a magnetic circuit having a first magnetic gap and a second magnetic gap. Both the first magnetic gap and the second magnetic gap are open on one axial side (upper side). The second magnetic gap is located radially outward and below the first magnetic gap.

[0003] International Publication No. 2022 / 040350

[0004] The present disclosure aims to provide a speaker that includes a magnetic circuit having a first magnetic gap and a second magnetic gap, and that makes it easy to ensure magnetic flux density in the second magnetic gap.

[0005] A speaker according to a first aspect is a speaker comprising: a first driving unit including a first coil; a second driving unit including a second coil having a diameter larger than that of the first coil; and a magnetic circuit having a first magnetic gap in which the first coil is disposed and a second magnetic gap in which the second coil is disposed, wherein the first magnetic gap and the second magnetic gap are both open to an upper side which is one axial side, and the second magnetic gap is located below the first magnetic gap which is the other axial side, and the magnetic circuit has a first magnetic path which passes through both the first magnetic gap and the second magnetic gap, and a second magnetic path which passes through the first magnetic gap and the second magnetic gap. and a second magnetic path that passes through only the second magnetic gap in the air gap, the magnetic circuit having a cylindrical magnetic member that forms a portion of the first magnetic path between the outer forming surface of the first magnetic gap and the inner forming surface of the second magnetic gap, and a first magnetic path magnet that mainly provides magnetic flux to the first magnetic path, a detour magnetic path forming portion that forms a portion of the first magnetic path between the outer forming surface of the second magnetic gap and the inner forming surface of the first magnetic gap, and a second magnetic path magnet that mainly provides magnetic flux to the second magnetic path, and a first space that radially separates the cylindrical magnetic member and the detour magnetic path forming portion is formed below the first magnetic gap.

[0006] In this aspect, the speaker includes a first driving unit including a first coil, a second driving unit including a second coil, and a magnetic circuit having a first magnetic gap in which the first coil is disposed and a second magnetic gap in which the second coil is disposed. The second coil has a larger diameter than the first coil. Both the first magnetic gap and the second magnetic gap are open on one axial side, i.e., an upper side. The second magnetic gap is located below the first magnetic gap, i.e., the other axial side.

[0007] In this aspect, the magnetic circuit forms a first magnetic path and a second magnetic path. The first magnetic path is a magnetic path that passes through both the first magnetic gap and the second magnetic gap. The second magnetic path is a magnetic path that passes only through the second magnetic gap. The magnetic circuit includes a cylindrical magnetic member that forms a portion of the first magnetic path between the outer surface of the first magnetic gap and the inner surface of the second magnetic gap, and a detour magnetic path forming portion that forms a portion of the first magnetic path between the outer surface of the second magnetic gap and the inner surface of the first magnetic gap. The detour magnetic path forming portion has a first magnetic path magnet that mainly provides magnetic flux to the first magnetic path. Therefore, the first magnetic path magnet can ensure the magnetic flux density of the first magnetic gap and the second magnetic gap.

[0008] In this embodiment, the magnetic circuit includes a second magnetic path magnet. The second magnetic path magnet mainly provides magnetic flux to the second magnetic path. Therefore, the second magnetic path magnet can ensure the magnetic flux density of the second magnetic gap.

[0009] In this aspect, a space (first space) that radially separates the cylindrical magnetic member and the bypass magnetic path forming portion is formed below the first magnetic gap, which makes it difficult for a magnetic path (third magnetic path) that passes only through the first magnetic gap out of the first and second magnetic gaps to be formed, making it easier to ensure the magnetic flux density of the second magnetic gap.

[0010] In the embodiment described below, the first drive unit is a drive unit for outputting sound, and the second drive unit is a drive unit for canceling out vibration of the entire speaker caused by the first drive unit. However, the first drive unit and the second drive unit of this embodiment are not limited to these drive units. For example, both the first drive unit and the second drive unit may be drive units for outputting sound. Alternatively, the second drive unit may be a drive unit for outputting sound, and the first drive unit may be a drive unit for canceling out vibration of the entire speaker caused by the second drive unit.

[0011] A speaker according to a second aspect is the speaker according to the first aspect, wherein the first space is a space into which the first coil can enter.

[0012] In this aspect, the first space is a space into which the first coil can enter, and therefore, the first space can be used as a space into which the first coil can enter, making it easy to reduce the size of the speaker in the vertical direction.

[0013] In the speaker of the third aspect, in the second aspect, the magnet for the second magnetic path is composed of an annular magnet, and a second space into which the first coil can enter is formed radially inward of the annular magnet and below the first space.

[0014] In this embodiment, the second magnetic path magnet is an annular magnet. A second space into which the first coil can enter is formed radially inward of the annular magnet and below the first space. This makes it possible to create a space below the first space into which the first coil can enter, making it easier to downsize the speaker in the vertical direction.

[0015] A speaker according to a fourth aspect is any one of the first to third aspects, in which the bypass magnetic path forming portion comprises an upper magnetic member arranged above the first magnetic path magnet, and a lower magnetic member arranged below the first magnetic path magnet.

[0016] In this aspect, the detour magnetic path forming portion includes an upper magnetic member arranged above the first magnetic path magnet and a lower magnetic member arranged below the first magnetic path magnet. Therefore, since the first magnetic path magnet is sandwiched between the upper and lower magnetic members, a decrease in the magnetic force of the first magnetic path magnet can be suppressed. Furthermore, in a magnetic circuit having two magnetic gaps, leakage magnetic flux in the first magnetic gap can be suppressed, thereby increasing the magnetic flux density in the first magnetic gap.

[0017] A speaker according to a fifth aspect is the speaker of the fourth aspect, wherein the first space is formed between the cylindrical magnetic member and the lower magnetic member.

[0018] In this aspect, the first space is formed between the cylindrical magnetic member and the lower magnetic member, so that the cylindrical magnetic member and the lower magnetic member can be separated by the first space.

[0019] A sixth aspect of the speaker is the fourth or fifth aspect, in which the magnet for the second magnetic path is an annular magnet, and the lower magnetic member has an outer forming surface of the second magnetic gap.

[0020] In this embodiment, the second magnetic path magnet is composed of an annular magnet. The lower magnetic member has an outer surface that defines the second magnetic gap. This results in a structure in which a portion of the lower magnetic member passes radially inside the annular magnet that constitutes the second magnetic path magnet. As a result, the volume of the magnet (annular magnet) that constitutes the second magnetic path magnet can be reduced.

[0021] A speaker according to a seventh aspect is any one of the fourth to sixth aspects, wherein a recess recessed upward is formed at the radial center of the lower surface of the lower magnetic member.

[0022] In this aspect, a recess recessed upward is formed in the radial center of the lower surface of the lower magnetic member, which allows for a reduction in the weight of the magnetic circuit and, as a result, the weight of the speaker.

[0023] The speaker according to an eighth aspect is the seventh aspect, wherein the upper end of the recess is positioned above the lower surface of the second magnetic path magnet.

[0024] In this aspect, the upper end of the recess is located above the lower surface of the second magnetic path magnet. This allows the magnetic circuit and speaker to be even lighter. From the perspective of reducing the weight of the magnetic circuit and speaker, it is more preferable that the upper end of the recess is located above the upper surface of the second magnetic path magnet.

[0025] The speaker of the ninth aspect is any one of the first to eighth aspects, in which the first drive unit is a drive unit for producing sound, and the second drive unit is a drive unit for canceling out vibration of the entire speaker caused by the first drive unit.

[0026] In this aspect, the first drive unit is a drive unit for producing sound, and the second drive unit is a drive unit for canceling out the vibration of the entire speaker caused by the first drive unit. Therefore, the action of the second drive unit can suppress the vibration of the entire speaker. Specifically, by reversing the vibration of the first drive unit and the second drive unit, the vibration of the first drive unit transmitted to the frame can be canceled out, and the generation of unnecessary vibration transmitted to the frame can be suppressed.

[0027] According to the present disclosure, a speaker is provided that includes a magnetic circuit having a first magnetic gap and a second magnetic gap, and that makes it easy to ensure magnetic flux density in the second magnetic gap.

[0028] 1 is a cross-sectional end view of a speaker according to an embodiment, a cross-sectional end view of a magnetic circuit included in the speaker according to an embodiment, and a cross-sectional end view of a magnetic circuit according to a modified example.

[0029] First, an embodiment of a speaker according to the present disclosure will be described with reference to FIGS. 1 and 2. FIG.

[0030] FIG. 1 is a cross-sectional end view of a speaker 10 according to this embodiment, taken along a plane passing through a central axis AX.

[0031] The speaker 10 is mounted, for example, on the door of an automobile. The speaker 10 is, for example, a woofer or subwoofer, and is capable of reproducing low frequencies with a large input.

[0032] The speaker 10 has a structure that is symmetrical about a central axis AX in its main portion.

[0033] In the following description, the direction parallel to the central axis AX is referred to as the axial direction, one axial side is referred to as the upper side, and the other axial side is referred to as the lower side. The direction perpendicular to the central axis AX is referred to as the radial direction, with the radial side closer to the central axis AX referred to as the axial inner side and the radial side farther from the central axis AX referred to as the axial outer side.

[0034] The speaker 10 has a first drive unit 20 that vibrates to produce sound, a second drive unit 30 that vibrates to offset the vibration of the entire speaker 10 caused by the first drive unit 20, a magnetic circuit 40, and a frame 50 that supports these.

[0035] (First Driving Unit 20 ) The first driving unit 20 includes a first bobbin 21 , a first coil 22 , a diaphragm 24 , an edge 25 , a cap 26 , a coupler 23 , and a first damper 27 .

[0036] The first bobbin 21 has a cylindrical shape. The first coil 22 is formed on the outer peripheral surface of the lower end of the first bobbin 21.

[0037] The diaphragm 24 is a member that radiates sound by vibrating. The diaphragm 24 has a circular hole in the center and extends radially outward and upward from the inner edge that defines the circular hole. The inner edge of the diaphragm 24 is joined to the coupler 23. The outer edge of the diaphragm 24 is connected to the frame 50 via an edge 25.

[0038] The first damper 27 supports the first bobbin 21 so that it can vibrate in the axial direction. The first damper 27 is provided radially outward of the first bobbin 21. The first damper 27 is composed of a single elastic body 27A. The elastic body 27A has a circular hole in its center and is an annular disk-shaped elastic body that extends radially outward from the inner edge that defines the circular hole. The inner edge of the elastic body 27A is joined to the outer edge of the coupler 23, and the outer edge of the elastic body 27A is joined to the frame 50.

[0039] The cap 26 is a member that vibrates to radiate sound. The cap 26 covers the first bobbin 21 and the coupler 23 from above. The outer edge of the cap 26 is joined to the upper surface of the diaphragm 24.

[0040] The coupler 23 is a member that vibrates to radiate sound. The coupler 23 is a member that is joined to the outer periphery of the first bobbin 21, and connects the first bobbin 21 to the diaphragm 24 and also connects the first bobbin 21 to the first damper 27.

[0041] (Second Driving Unit 30 ) The second driving unit 30 includes a second bobbin 31 , a second coil 32 , a second damper 37 , a spacer 38 , and a weight 39 .

[0042] The second bobbin 31 has a cylindrical shape. The second bobbin 31 has a larger diameter than the first bobbin 21. The second coil 32 is formed on the outer peripheral surface of the lower end of the second bobbin 31. In the inactive state (a state in which the speaker 10 is not activated) shown in FIG. 1 , the upper end of the second bobbin 31 is located above the lower end of the first bobbin 21.

[0043] The second damper 37 supports the second bobbin 31 so that it can vibrate in the axial direction. The second damper 37 is provided radially outward of the second bobbin 31. The second damper 37 is composed of a first elastic body 37A and a second elastic body 37B that are spaced apart in the axial direction. The first elastic body 37A and the second elastic body 37B are both annular, disk-shaped elastic bodies that have a circular hole in their centers and extend radially outward from the inner edge that defines the circular hole. The inner edge portions of the first elastic body 37A and the second elastic body 37B are bonded to the outer peripheral surface of the second bobbin 31. The outer edge portions of the first elastic body 37A and the second elastic body 37B are bonded to the frame 50 together with a spacer 38 that maintains the axial distance between the first elastic body 37A and the second elastic body 37B.

[0044] The weight 39 functions to increase the mass of the vibrating portion supported by the second damper 37. Increasing the mass of the vibrating portion supported by the second damper 37 makes it possible to reduce the amplitude of the second drive unit 30 while maintaining the effect of canceling out the vibration of the entire speaker 10 caused by the second drive unit 30 (unwanted vibrations generated in the frame 50 by driving the first drive unit 20). The weight 39 has an annular shape. The weight 39 is provided near the inner edge of the second damper 37. The weight 39 is provided between the first elastic body 37A and the second elastic body 37B.

[0045] 2, the magnetic circuit 40 includes an upper magnetic member 41, a first magnetic path magnet 42, a cylindrical magnetic member 43, a second magnetic path magnet 44, and a lower magnetic member 45. These magnetic members 41, 43, and 45 and the magnets 42 and 44 are joined together with an adhesive or the like.

[0046] The magnetic circuit 40 has a first magnetic gap G1 and a second magnetic gap G2. Both the first magnetic gap G1 and the second magnetic gap G2 are open on the upper side. The second magnetic gap G2 is located radially outward and below the first magnetic gap G1.

[0047] The magnetic circuit 40 is integrally formed. That is, the magnetic circuit 40 includes the first magnetic gap G1 and the second magnetic gap G2.

[0048] The magnetic circuit 40 forms a first magnetic path 71 and a second magnetic path 72. The first magnetic path 71 is a magnetic path that passes through both the first magnetic gap G1 and the second magnetic gap G2. The second magnetic path 72 is a magnetic path that passes through only the second magnetic gap G2 out of the first magnetic gap G1 and the second magnetic gap G2.

[0049] The portion of the first magnetic path 71 between the outer forming surface G1b of the first magnetic gap G1 and the inner forming surface G2a of the second magnetic gap G2 is formed by the cylindrical magnetic member 43. The portion of the first magnetic path 71 between the outer forming surface G2b of the second magnetic gap G2 and the inner forming surface G1a of the first magnetic gap G1 is formed by the lower magnetic member 45, the first magnetic path magnet 42, and the upper magnetic member 41. Hereinafter, the lower magnetic member 45, the first magnetic path magnet 42, and the upper magnetic member 41 may be collectively referred to as the detour magnetic path forming portions 41, 42, 45. Note that the inner forming surface of the magnetic gap refers to the surface located radially inward of the magnetic gap, and the outer forming surface of the magnetic gap refers to the surface located radially outward of the magnetic gap.

[0050] The portion of the second magnetic path 72 that does not overlap with the first magnetic path 71 is formed by the second magnetic path magnet 44. The cylindrical magnetic member 43 and the detour magnetic path forming portions 41, 42, 45 are connected by the second magnetic path magnet 44, thereby forming the second magnetic path 72 that passes through the second magnetic gap G2 but does not pass through the first magnetic gap G1. The cylindrical magnetic member 43 and the detour magnetic path forming portions 41, 42, 45 are connected only by the second magnetic path magnet 44.

[0051] The lower magnetic member 45 has a bottom portion 45 a, a cylindrical portion 45 b extending upward from the outer edge of the bottom portion 45 a, a protrusion 45 c extending upward from the center of the bottom portion 45 a, and a flange 45 d extending radially outward from the upper end of the cylindrical portion 45 b. The flange 45 d is attached to the frame 50 (see FIG. 1 ).

[0052] An upwardly recessed recess 45e is formed at the radial center of the lower surface of the lower magnetic member 45. The recess 45e has a side surface 45e1 and a bottom surface 45e2. The bottom surface 45e2 is a flat surface whose normal direction faces downward. The side surface 45e1 is inclined with respect to the axial direction.

[0053] The first magnetic path magnet 42 is disposed on the upper surface of the protrusion 45c of the lower magnetic member 45. The first magnetic path magnet 42 has a cylindrical shape. The first magnetic path magnet 42 mainly applies magnetic flux to the first magnetic path 71.

[0054] The second magnetic path magnet 44 is disposed on the upper surface of the bottom portion 45a of the lower magnetic member 45. The second magnetic path magnet 44 is an annular magnet. The second magnetic path magnet 44, which is an annular magnet, is disposed so as to surround the convex portion 45c of the lower magnetic member 45. In other words, the convex portion 45c of the lower magnetic member 45 is disposed radially inward of the second magnetic path magnet 44. The second magnetic path magnet 44 mainly provides magnetic flux to the second magnetic path 72.

[0055] A first space 61 is formed between the outer peripheral surface of the protrusion 45c of the lower magnetic member 45 and the inner peripheral surface of the cylindrical magnetic member 43. The first space 61 is located below the first magnetic gap G1. The first space 61 is a space into which the first coil 22 can enter.

[0056] A space (second space 62) is formed between the outer peripheral surface of the protrusion 45c of the lower magnetic member 45 and the inner peripheral surface of the second magnetic path magnet 44. The second space 62 is located below the first magnetic gap G1. The second space 62 is a space into which the first coil 22 can enter.

[0057] The cylindrical magnetic member 43 is disposed on the upper surface of the second magnetic path magnet 44. The cylindrical magnetic member 43 has a cylindrical tube portion 43a and an outer protrusion portion 43b that protrudes radially outward from the lower end of the tube portion 43a. The inner circumferential surface at the upper end of the tube portion 43a functions as the outer forming surface G1b of the first magnetic gap G1. The radially outer surface of the outer protrusion portion 43b functions as the inner forming surface G2a of the second magnetic gap G2. The inner diameter of the tube portion 43a is approximately the same as the inner diameter of the second magnetic path magnet 44. The outer diameter of the tube portion 43a is smaller than the outer diameter of the second magnetic path magnet 44. The radially outer surface of the outer protrusion portion 43b (the inner forming surface G2a of the second magnetic gap G2) is located radially outward from the outer circumferential surface of the second magnetic path magnet 44.

[0058] The upper magnetic member 41 is disposed on the upper surface of the first magnetic path magnet 42. The upper magnetic member 41 has a generally cylindrical shape. The diameter of the upper magnetic member 41 is larger than the diameter of the first magnetic path magnet 42. The outer peripheral surface of the upper magnetic member 41 functions as the inner forming surface G1a of the first magnetic gap G1.

[0059] A recess 41a recessed downward is formed at the radial center of the top surface of the upper magnetic member 41. This allows the magnetic field to be concentrated toward the first magnetic gap G1. Furthermore, by reducing the apparent cross-sectional area of ​​the upper magnetic member 41, which serves as the iron core, it is possible to suppress the generation of inductance, i.e., the generation of AC magnetic flux, thereby improving sound quality. This configuration also reduces weight.

[0060] (Frame 50) As shown in FIG. 1 , the frame 50 has a first support portion 51 that supports the outer edge portion of the edge 25, a second support portion 52 that supports the outer edge portion of the first damper 27, a third support portion 53 that supports the outer edge portion of the second damper 37, and a fourth support portion 54 that supports the magnetic circuit 40. The first support portion 51, the second support portion 52, and the third support portion 53 are joined to the edge 25, the first damper 27, and the second damper 37 at their upwardly facing surfaces, respectively. The magnetic circuit 40 is mechanically fixed to the fourth support portion 54. The first support portion 51 is located radially outward from the second support portion 52, the second support portion 52 is located radially outward from the third support portion 53, and the third support portion 53 is located radially outward from the fourth support portion 54. The first support portion 51 is located above the second support portion 52 , the second support portion 52 is located above the third support portion 53 , and the third support portion 53 is located above the fourth support portion 54 .

[0061] Next, the relationship between the magnetic circuit 40 and the first and second drive units 20 and 30 will be described.

[0062] As shown in FIG. 1 , the first coil 22 of the first driving unit 20 is disposed in the first magnetic gap G1. The first coil 22 is connected to a transmission path. The action of an electric signal from the transmission path and the magnetic field of the first magnetic gap G1 causes the first bobbin 21 to vibrate together with the first coil 22, which in turn vibrates the first driving unit 20, including the diaphragm 24. This causes sound to be emitted. At this time, a vibration force is generated in the speaker 10 in response to the vibration of the first driving unit 20. This vibration force is transmitted via the frame 50, causing the entire speaker 10 and the object to which the speaker 10 is attached (for example, the panel of a side door of an automobile) to vibrate.

[0063] The second coil 32 of the second driving unit 30 is disposed in the second magnetic gap G2. The second coil 32 is connected to a transmission path, and the action of an electric signal from the transmission path and the magnetic field of the second magnetic gap G2 causes the second bobbin 31 to vibrate together with the second coil 32, which in turn vibrates the second driving unit 30 including the weight 39. The first driving unit 20 and the second driving unit 30 are configured to operate in opposite phases to each other. This cancels out the excitation forces generated in response to the vibration of the first driving unit 20, thereby suppressing vibration of the entire speaker 10.

[0064] <Operation and Effect> Next, the operation and effect of this embodiment will be described.

[0065] 1 , the speaker 10 includes a first driving unit 20 including a first coil 22, a second driving unit 30 including a second coil 32, and a magnetic circuit 40 having a first magnetic gap G1 in which the first coil 22 is disposed and a second magnetic gap G2 in which the second coil 32 is disposed. The second coil 32 has a larger diameter than the first coil 22. The first magnetic gap G1 and the second magnetic gap G2 are both open to the upper side, which is one axial side. The second magnetic gap G2 is located below the first magnetic gap G1, which is the other axial side.

[0066] In this embodiment, as shown in FIG. 2 , the magnetic circuit 40 forms a first magnetic path 71 and a second magnetic path 72. The first magnetic path 71 is a magnetic path that passes through both the first magnetic gap G1 and the second magnetic gap G2. The second magnetic path 72 is a magnetic path that passes only through the second magnetic gap G2. The magnetic circuit 40 includes a cylindrical magnetic member 43 that forms a portion of the first magnetic path 71 between the outer surface G1b of the first magnetic gap G1 and the inner surface G2a of the second magnetic gap G2, and detour magnetic path forming portions 41, 42, and 45 that form a portion of the first magnetic path 71 between the outer surface G2b of the second magnetic gap G2 and the inner surface G1a of the first magnetic gap G1. The detour magnetic path forming portions 41, 42, and 45 include a first magnetic path magnet 42 that mainly forms the first magnetic path 71. Therefore, the first magnetic path magnet 42 can ensure the magnetic flux density of the first magnetic gap G1 and the second magnetic gap G2.

[0067] In this embodiment, the magnetic circuit 40 also includes a second magnetic path magnet 44. The second magnetic path magnet 44 forms the first magnetic path 71 and the second magnetic path 72, and mainly forms the second magnetic path 72. Therefore, the second magnetic path magnet 44 can ensure the magnetic flux density of the second magnetic gap G2.

[0068] In this embodiment, a space (first space 61) is formed below the first magnetic gap G1, radially separating the cylindrical magnetic member 43 from the detour magnetic path forming portions 41, 42, 45. This makes it difficult to form a magnetic path (third magnetic path) that passes only through the first magnetic gap G1 out of the first magnetic gap G1 and the second magnetic gap G2, and as a result, it becomes easier to ensure the magnetic flux density of the second magnetic gap G2.

[0069] In the present embodiment, the first space 61 is a space into which the first coil 22 can enter. Therefore, the first space 61 can be used as a space into which the first coil 22 can enter, which makes it easier to reduce the size of the speaker 10 in the vertical direction.

[0070] Furthermore, in this embodiment, the second magnetic path magnet 44 is configured as an annular magnet. A second space 62, into which the first coil 22 can enter, is formed radially inward of the annular magnet and below the first space 61. This allows a space below the first space 61 into which the first coil 22 can enter, making it easier to downsize the speaker 10 in the vertical direction. The inner diameter of the second magnetic path magnet 44 may be smaller than the inner diameter of the cylindrical portion 43a. The outer surface G1b of the first magnetic gap G1 may also be smaller than the inner diameter of the cylindrical portion 43a. In particular, in this embodiment, the inner diameter of the cylindrical magnetic member 43 and the inner diameter of the second magnetic path magnet 44 are substantially the same, further suppressing the formation of a third magnetic path and making it easier to ensure the magnetic flux density of the first magnetic gap G1 and the second magnetic gap G2.

[0071] Furthermore, in this embodiment, the detour magnetic path forming parts 41, 42, 45 include an upper magnetic member 41 arranged above the first magnetic path magnet 42, and a lower magnetic member 45 arranged below the first magnetic path magnet 42. Therefore, the first magnetic path magnet 42 is sandwiched between the upper magnetic member 41 and the lower magnetic member 45, which makes it possible to suppress a decrease in the magnetic force of the first magnetic path magnet 42.

[0072] In this embodiment, the first space 61 is formed between the cylindrical magnetic member 43 and the lower magnetic member 45. Therefore, the cylindrical magnetic member 43 and the lower magnetic member 45 can be separated by the first space 61.

[0073] Furthermore, in this embodiment, the second magnetic path magnet 44 is configured as an annular magnet. The lower magnetic member 45 has an outer forming surface G2b of the second magnetic gap G2. This results in a structure in which a portion of the lower magnetic member 45 (the convex portion 45c) passes radially inside the annular magnet that constitutes the second magnetic path magnet 44. As a result, the volume of the magnet (annular magnet) that constitutes the second magnetic path magnet 44 can be reduced.

[0074] In this embodiment, a recess 45e recessed upward is formed in the radial center of the lower surface of the lower magnetic member 45. This allows for a reduction in the weight of the magnetic circuit 40. As a result, the weight of the speaker 10 can be reduced.

[0075] Furthermore, in this embodiment, the upper end (bottom surface 45e2) of the recess 45e is located higher than the lower surface of the second magnetic path magnet 44. This allows for even greater weight reduction of the magnetic circuit 40 and the speaker 10. In particular, in this embodiment, the upper end (bottom surface 45e2) of the recess 45e is located higher than the upper surface of the second magnetic path magnet 44, which significantly reduces the weight of the magnetic circuit 40 and the speaker 10.

[0076] 1, in this embodiment, the first drive unit 20 is a drive unit for producing sound, and the second drive unit 30 is a drive unit for canceling out the vibration of the entire speaker 10 caused by the first drive unit 20. Therefore, the vibration of the entire speaker 10 can be suppressed.

[0077] (Modification) Next, a magnetic circuit 80 according to a modification will be described with reference to Fig. 3. Note that descriptions of parts common to the magnetic circuit 40 will be omitted where appropriate.

[0078] 3, the magnetic circuit 80 includes an upper magnet 81, a first magnetic member 82, a cylindrical magnetic member 83, a lower magnet 84, and a second magnetic member 85. The upper magnet 81 and the lower magnet 84 are arranged so that their like poles face each other, i.e., so that they repel each other.

[0079] The magnetic circuit 80 has a first magnetic gap G1 and a second magnetic gap G2.

[0080] The magnetic circuit 80 forms a first magnetic path 71 and a second magnetic path 72 .

[0081] The portion of the first magnetic path 71 between the outer forming surface G1b of the first magnetic gap G1 and the inner forming surface G2a of the second magnetic gap G2 is formed by a cylindrical magnetic member 83. The portion of the first magnetic path 71 between the outer forming surface G2b of the second magnetic gap G2 and the inner forming surface G1a of the first magnetic gap G1 is formed by a second magnetic member 85, a radially inner portion 84a of the lower magnet 84, a first magnetic member 82, and an upper magnet 81. That is, in the magnetic circuit 80 according to the modified example, the second magnetic member 85, the radially inner portion 84a of the lower magnet 84, the first magnetic member 82, and the upper magnet 81 function as the detour magnetic path forming portions 81, 82, 84a, 85. The upper magnet 81 and the radially inner portion 84a of the lower magnet 84 mainly provide magnetic flux to the first magnetic path 71 and correspond to the "first magnetic path magnet."

[0082] The portion of the second magnetic path 72 that does not overlap with the first magnetic path 71 is formed by the radially outer portion 84b of the lower magnet 84. The radially outer portion 84b of the lower magnet 84 mainly provides magnetic flux to the second magnetic path 72 and corresponds to the "second magnetic path magnet." The cylindrical magnetic member 83 and the detour magnetic path forming portions 81, 82, 84a, and 85 are connected by the radially outer portion 84b of the lower magnet 84, thereby forming the second magnetic path 72 that passes through the second magnetic gap G2 but does not pass through the first magnetic gap G1. The cylindrical magnetic member 83 and the detour magnetic path forming portions 81, 82, 84a, and 85 are connected only by the radially outer portion 84b of the lower magnet 84.

[0083] The second magnetic member 85 has a bottom portion 85a, a cylindrical portion 85b standing upward from the outer edge of the bottom portion 85a, and a flange 85d extending radially outward from the upper end of the cylindrical portion 85b.

[0084] The lower magnet 84 is disposed on the upper surface of the bottom portion 85a of the second magnetic member 85. The lower magnet 84 is a cylindrical magnet.

[0085] The cylindrical magnetic member 83 is disposed on the upper surface of the lower magnet 84. The cylindrical magnetic member 83 has a cylindrical tube portion 83a and an outer protrusion portion 83b that protrudes radially outward from the lower end of the tube portion 83a. The inner circumferential surface at the upper end of the tube portion 83a functions as the outer defining surface G1b of the first magnetic gap G1. The radially outer surface of the outer protrusion portion 83b functions as the inner defining surface G2a of the second magnetic gap G2.

[0086] The first magnetic member 82 is disposed on the upper surface of the lower magnet 84. The first magnetic member 82 has a cylindrical main body 82a and an outer protrusion 82b that protrudes radially outward from the upper end of the main body 82a. The outer peripheral surface of the outer protrusion 82b of the first magnetic member 82 functions as the inner forming surface G1a of the first magnetic gap G1.

[0087] The upper magnet 81 is disposed on the upper surface of the first magnetic member 82. The upper magnet 81 is a cylindrical magnet.

[0088] An annular space is formed between the inner circumferential surface of the cylindrical magnetic member 83 and the outer circumferential surface of the first magnetic member 82. Within this space, the space between the outer circumferential surface of the outer protrusion 82b of the first magnetic member 82 and the inner circumferential surface of the cylindrical magnetic member 83 forms the first magnetic gap G1, and the space below the second magnetic gap G2 forms the first space 61. The first space 61 is a space into which the first coil 22 can enter. The first space 61 radially separates the cylindrical magnetic member 83 and the bypass magnetic path forming portions 81, 82, 84a, 85 (specifically, the first magnetic member 82).

[0089] (Other Modifications) In the magnetic circuit 80, the radially inner portion 84a and the radially outer portion 84b of the lower magnet 84 may be configured as two separate magnets. That is, the lower magnet 84 may be configured as two magnets: a cylindrical inner magnet arranged radially inside, and an annular outer magnet arranged radially outside the inner magnet. In this case, a space (second space, see second space 62 in FIG. 2 ) into which the first coil 22 can enter may be formed between the radially inner portion 84a (inner magnet) of the lower magnet 84 and the radially outer portion 84b (outer magnet) of the lower magnet 84.

[0090] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. The following is a supplementary explanation for clarity.

[0091] In the above embodiment, the first driving unit 20 includes the coupler 23 that connects the first bobbin 21 and the diaphragm 24 and also connects the first bobbin 21 and the first damper 27. However, the first driving unit of the present disclosure is not limited to this and does not need to include a coupler. In other words, the first bobbin 21 and the diaphragm 24 may be directly connected, or the first bobbin 21 and the first damper 27 may be directly connected.

[0092] In the above embodiment, the first space 61 is a space into which the first coil 22 can enter. However, the first space of the present disclosure is not limited to this, and may be a space into which the first coil cannot enter.

[0093] In the above-described embodiments, the magnetic circuits 40 and 80 have flanges 45d and 85d, respectively. However, the magnetic circuits of the present disclosure are not limited to this and may not have flanges.

[0094] REFERENCE SIGNS LIST 10 Speaker 20 First driving unit 22 First coil 30 Second driving unit 32 Second coil 40 Magnetic circuit 41, 42, 45 Detour magnetic path forming portion 41 Upper magnetic member 42 Magnet for first magnetic path 43 Cylindrical magnetic member 44 Magnet for second magnetic path 45 Lower magnetic member 45e Recess 45e2 Bottom surface (upper end of recess) 61 First space 62 Second space 71 First magnetic path 72 Second magnetic path 80 Magnetic circuit 81, 82, 84a, 85 Detour magnetic path forming portion 81 First magnet (magnet for first magnetic path) 82 First magnetic member 83 Cylindrical magnetic member 84 Second magnet 84a Radially inner portion (magnet for first magnetic path) 84b Radially outer portion (magnet for second magnetic path) 85 Second magnetic member G1 First magnetic gap G1a Inner forming surface G1b Outer forming surface G2 Second magnetic gap G2a Inner forming surface G2b Outer forming surface

Claims

1. A speaker comprising: a first driving unit having a first coil; a second driving unit having a second coil with a diameter larger than that of the first coil; and a magnetic circuit having a first magnetic gap in which the first coil is disposed and a second magnetic gap in which the second coil is disposed, wherein both the first magnetic gap and the second magnetic gap are open on the upper side which is one side in the axial direction, the second magnetic gap is located on the lower side which is the other side in the axial direction with respect to the first magnetic gap, the magnetic circuit forms a first magnetic path passing through both of the first magnetic gap and the second magnetic gap, and a second magnetic path passing through only the second magnetic gap among the first magnetic gap and the second magnetic gap, the magnetic circuit includes a cylindrical magnetic member forming a portion between an outer forming surface of the first magnetic gap and an inner forming surface of the second magnetic gap in the first magnetic path, a first magnet for the first magnetic path mainly providing magnetic flux to the first magnetic path, a detour magnetic path forming portion forming a portion between an outer forming surface of the second magnetic gap and an inner forming surface of the first magnetic gap in the first magnetic path, and a second magnet for the second magnetic path mainly providing magnetic flux to the second magnetic path, and a first space is formed below the first magnetic gap to radially separate the cylindrical magnetic member and the detour magnetic path forming portion.

2. The speaker according to claim 1, wherein the first space is a space into which the first coil can enter.

3. The speaker according to claim 2, wherein the second magnet for the second magnetic path is constituted by an annular magnet, and a second space into which the first coil can enter is formed below the first space and inside the radial direction of the annular magnet.

4. The speaker according to claim 1, wherein the detour magnetic path forming portion includes an upper magnetic member disposed above the first magnet for the first magnetic path and a lower magnetic member disposed below the first magnet for the first magnetic path.

5. The speaker according to claim 4, wherein the first space is formed between the cylindrical magnetic member and the lower magnetic member.

6. The speaker according to claim 4, wherein the second magnet for the second magnetic path is constituted by an annular magnet, and the lower magnetic member has an outer forming surface of the second magnetic gap.

7. The speaker according to claim 4, wherein a concave portion recessed upward is formed at the radial center of the lower surface of the lower magnetic member.

8. The upper end of the concave portion is located above the lower surface of the magnet for the second magnetic path. The speaker according to claim 7.

9. The first driving unit is a driving unit for producing sound, and the second driving unit is a driving unit for canceling the vibration of the entire speaker caused by the first driving unit. The speaker according to claim 1.

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