Speaker

Abstract

To provide a speaker for facilitating securing a magnetic flux density of a second magnetic gap.SOLUTION: A first magnetic path 71 and a second magnetic path 72 are formed in a magnetic circuit 40 included in a speaker 10. The magnetic circuit 40 includes: a cylindrical magnetic member 43 for forming a portion between an outer formation surface G1b of a first magnetic gap G1 and an inner formation surface G2a of a second magnetic gap G2 in the first magnetic path 71; and detour magnetic path formation parts 41, 42, 45 for forming a portion between an outer formation surface G2b of the second magnetic gap G2 and an inner formation surface G1a of the first magnetic gap G1 in the first magnetic path 71. A first space 61 for radially separating the cylindrical magnetic member 43 from the detour magnetic path formation parts 41, 42, 45 is formed under the first magnetic gap G1.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a speaker.

Background Art

[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 outside and below the first magnetic gap.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure aims to provide a speaker including a magnetic circuit having a first magnetic gap and a second magnetic gap, and in which it is easy to ensure the magnetic flux density of the second magnetic gap.

Means for Solving the Problems

[0005] The speaker according to the first aspect includes 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. The first magnetic gap and the second magnetic gap are both open upward, which is one side in the axial direction. The second magnetic gap is located below, which is the other side in the axial direction, than 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, and has a first magnet for mainly applying magnetic flux to the first magnetic path. The magnetic circuit includes 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 mainly applying magnetic flux to the second magnetic path. 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 diameter larger than that of the first coil. The first magnetic gap and the second magnetic gap are both open upward, which is one side in the axial direction. The second magnetic gap is located below, which is the other side in the axial direction, than the first magnetic gap.

[0007] In addition, 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 through only the second magnetic gap among the first magnetic gap and the second magnetic gap. The magnetic circuit includes a cylindrical magnetic member that forms a portion between the outer formation surface of the first magnetic gap and the inner formation surface of the second magnetic gap in the first magnetic path, and a detour magnetic path forming portion that forms a portion between the outer formation surface of the second magnetic gap and the inner formation surface of the first magnetic gap in the first magnetic path. And the detour magnetic path forming portion has a magnet for the first magnetic path that mainly provides magnetic flux to the first magnetic path. Therefore, the magnet for the first magnetic path can ensure the magnetic flux density of the first magnetic gap and the second magnetic gap.

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

[0009] In addition, in this aspect, a space (first space) that radially separates the cylindrical magnetic member and the detour magnetic path forming portion is formed below the first magnetic gap. Therefore, it becomes difficult to form a magnetic path (third magnetic path) that passes through only the first magnetic gap among the first magnetic gap and the second magnetic gap. As a result, it becomes easier to ensure the magnetic flux density of the second magnetic gap.

[0010] In the embodiments described later, the first driving unit is a driving unit for generating sound, and the second driving unit is a driving unit for canceling the vibration of the entire speaker by the first driving unit. However, the first driving unit and the second driving unit of this aspect are not limited to these driving units. For example, both the first driving unit and the second driving unit may be driving units for generating sound. Also, the second driving unit may be a driving unit for generating sound, and the first driving unit may be a driving unit for canceling the vibration of the entire speaker by the second driving unit.

[0011] In the second aspect, in the first aspect, 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. Therefore, since the first space can be used as a space into which the first coil can enter, it is easy to miniaturize the speaker in the vertical direction.

[0013] In 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 below the first space inside the radial direction of the annular magnet.

[0014] In this 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 below the first space inside the radial direction of the annular magnet. Therefore, since a space into which the first coil can enter can also be created below the first space, it is easy to miniaturize the speaker in the vertical direction.

[0015] In the fourth aspect, in any one of the first to third aspects, the detour magnetic path forming portion includes an upper magnetic member disposed above the magnet for the first magnetic path and a lower magnetic member disposed below the magnet for the first magnetic path.

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

[0017] In the fifth aspect, in the fourth aspect, 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. Therefore, the cylindrical magnetic member and the lower magnetic member can be separated by the first space.

[0019] The speaker according to the sixth aspect is, in the fourth or fifth aspect, wherein the magnet for the second magnetic path is formed of an annular magnet, and the lower magnetic member has an outer formation surface of the second magnetic gap.

[0020] In this aspect, the magnet for the second magnetic path is formed of an annular magnet. The lower magnetic member has an outer formation surface of the second magnetic gap. Therefore, a part of the lower magnetic member passes through the radially inner side of the annular magnet constituting the magnet for the second magnetic path. As a result, the volume of the magnet (annular magnet) constituting the magnet for the second magnetic path can be reduced.

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

[0022] In this aspect, a recess that is recessed upward is formed at the radial center of the lower surface of the lower magnetic member. Therefore, the magnetic circuit can be lightened. As a result, the speaker can be lightened.

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

[0024] In this aspect, the upper end of the recess is located above the lower surface of the magnet for the second magnetic path. Therefore, the magnetic circuit and the speaker can be further lightened. From the viewpoint of lightening the magnetic circuit and the speaker, it is more preferable that the upper end of the recess is located above the upper surface of the magnet for the second magnetic path.

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

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

Advantages of the Invention

[0027] According to the present disclosure, there is provided a speaker including a magnetic circuit having a first magnetic gap and a second magnetic gap, which can easily secure the magnetic flux density of the second magnetic gap.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

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

[0030] FIG. 1 is a cross-sectional view of a plane passing through the central axis AX of the speaker 10 according to the present embodiment.

[0031] The speaker 10 is mounted on, for example, the door of an automobile. The speaker 10 is, for example, a woofer or a subwoofer, and can reproduce bass at a large input.

[0032] The speaker 10 has a structure that is axially symmetric with respect to the central axis AX in its main part.

[0033] In the following description, the direction parallel to the central axis AX is referred to as the axial direction, one side in the axial direction is referred to as the upper side, and the other side in the axial direction is referred to as the lower side. Further, the direction perpendicular to the central axis AX is referred to as the radial direction, the side approaching the central axis AX in the radial direction is referred to as the inner side in the axial direction, and the side moving away from the central axis AX in the radial direction is referred to as the outer side in the axial direction.

[0034] The speaker 10 includes a first driving part 20 that vibrates to produce sound, a second driving part 30 that vibrates to cancel out the vibration of the entire speaker 10 caused by the first driving part 20, a magnetic circuit 40, and a frame 50 that supports these components.

[0035] (First Driving Part 20) The first driving part 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 side at 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 at the center and has a shape that extends radially outward and upward from the inner edge portion forming the circular hole. The inner edge portion of the diaphragm 24 is joined to the coupler 23. The outer edge portion of the diaphragm 24 is connected to the frame 50 via the edge 25.

[0038] The first damper 27 supports the first bobbin 21 so as to be axially vibratable. The first damper 27 is provided on the outer side in the radial direction 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 at the center and is an elastic body having an annular disc shape that extends radially outward from the inner edge portion forming the circular hole. The inner edge portion of the elastic body 27A is joined to the outer edge portion of the coupler 23, and the outer edge portion of the elastic body 27A is joined to the frame 50.

[0039] The cap 26 is a member that radiates sound by vibrating. 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 radiates sound by vibrating. The coupler 23 is a member joined to the outer peripheral side of the first bobbin 21, connects the first bobbin 21 and the diaphragm 24, and connects the first bobbin 21 and the first damper 27.

[0041] (Second drive unit 30) The second drive 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 side at the lower end of the second bobbin 31. In the non-operating state shown in FIG. 1 (the state where the speaker 10 is not operating), 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 as to be axially vibratable. The second damper 37 is provided on the radially outer side 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 arranged with an axial distance therebetween. Both the first elastic body 37A and the second elastic body 37B have a circular hole in the center and are elastic bodies having an annular disc shape extending radially outward from the inner edge portion forming the circular hole. The inner edge portions of the first elastic body 37A and the second elastic body 37B are joined 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 joined to the frame 50 together with a spacer 38 for maintaining 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. By increasing the mass of the vibrating portion supported by the second damper 37, it is possible to reduce the amplitude amount of the second drive unit 30 while maintaining the effect of canceling out the vibration of the entire speaker 10 by the second drive unit 30 (unnecessary vibration generated in the frame 50 due to the drive of the first drive unit 20). The weight 39 has an annular shape. The weight 39 is provided near the inner edge portion of the second damper 37. The weight 39 is provided between the first elastic body 37A and the second elastic body 37B.

[0045] (Magnetic circuit 40) As shown in FIG. 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, 45 and magnets 42, 44 are joined by 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 upward. The second magnetic gap G2 is located radially outside and below the first magnetic gap G1.

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

[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 of 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 among the first magnetic gap G1 and the second magnetic gap G2.

[0049] Among the first magnetic path 71, the portion between the outer formation surface G1b of the first magnetic gap G1 and the inner formation surface G2a of the second magnetic gap G2 is formed by the cylindrical magnetic member 43. Among the first magnetic circuit 71, the portion between the outer formation surface G2b of the second magnetic gap G2 and the inner formation surface G1a of the first magnetic gap G1 is formed by the lower magnetic member 45, the magnet 42 for the first magnetic circuit, and the upper magnetic member 41. Hereinafter, the lower magnetic member 45, the magnet 42 for the first magnetic circuit, and the upper magnetic member 41 may be collectively referred to as the bypass magnetic circuit forming portion 41, 42, 45. Note that the inner formation surface of the magnetic gap means the surface located on the radially inner side of the magnetic gap, and the outer formation surface of the magnetic gap means the surface located on the radially outer side of the magnetic gap.

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

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

[0052] A concave portion 45e that is recessed upward is formed at the radial center on the lower surface of the lower magnetic member 45. The concave portion 45e has a side surface 45e1 and a bottom surface 45e2. The bottom surface 45e2 is a plane whose normal direction is downward. The side surface 45e1 is inclined with respect to the axial direction.

[0053] The magnet 42 for the first magnetic circuit is disposed on the upper surface of the convex portion 45c of the lower magnetic member 45. The magnet 42 for the first magnetic circuit has a cylindrical shape. The magnet 42 for the first magnetic circuit mainly provides magnetic flux to the first magnetic circuit 71.

[0054] The magnet 44 for the second magnetic circuit is disposed on the upper surface of the bottom 45a of the lower magnetic member 45. The magnet 44 for the second magnetic circuit is an annular magnet. The magnet 44 for the second magnetic circuit, which is an annular magnet, is disposed so as to surround the convex portion 45c of the lower magnetic member 45. That is, the convex portion 45c of the lower magnetic member 45 is disposed inside the second magnetic circuit magnet 44 in the radial direction. The magnet 44 for the second magnetic circuit mainly provides magnetic flux to the second magnetic circuit 72.

[0055] A first space 61 is formed between the outer peripheral surface of the convex portion 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 convex portion 45c of the lower magnetic member 45 and the inner peripheral surface of the magnet 44 for the second magnetic circuit. 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 magnet 44 for the second magnetic circuit. The cylindrical magnetic member 43 has a cylindrical portion 43a having a cylindrical shape, and an outer protruding portion 43b protruding radially outward from the lower end portion of the cylindrical portion 43a. The inner peripheral surface at the upper end of the cylindrical portion 43a functions as an outer formation surface G1b of the first magnetic gap G1. The radially outer surface of the outer protruding portion 43b functions as an inner formation surface G2a of the second magnetic gap G2. The inner diameter of the cylindrical portion 43a is substantially the same as the inner diameter of the magnet 44 for the second magnetic circuit. The outer diameter of the cylindrical portion 43a is smaller than the outer diameter of the magnet 44 for the second magnetic circuit. The radially outer surface of the outer protruding portion 43b (the inner formation surface G2a of the second magnetic gap G2) is located radially outside the outer peripheral surface of the magnet 44 for the second magnetic circuit.

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

[0059] At the radial center on the upper surface of the upper magnetic member 41, a concave portion 41a that is recessed downward is formed. Thereby, the direction of the magnetic field can be concentrated on the first magnetic gap G1. Further, by reducing the apparent cross-sectional area of the upper magnetic member 41 that serves as the iron core, the generation of inductance, that is, the generation of alternating magnetic flux can be suppressed, and high sound quality can be achieved. Also, with this configuration, weight reduction is achieved.

[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, respectively, on the surfaces facing upward. The magnetic circuit 40 is mechanically fixed to the fourth support portion 54. The first support portion 51 is located radially outside the second support portion 52, the second support portion 52 is located radially outside the third support portion 53, and the third support portion 53 is located radially outside 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 driving portion 20 and the second driving portion 30 will be described.

[0062] As shown in FIG. 1, a first coil 22 of a first driving unit 20 is disposed in a first magnetic gap G1. The first coil 22 is connected to a transmission path. Due to the action of an electric signal from the transmission path and the magnetic field of the first magnetic gap G1, the first bobbin 21 vibrates together with the first coil 22. As a result, the first driving unit 20 including the diaphragm 24 and the like vibrates. Thereby, sound is radiated. 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 through the frame 50 and causes the entire speaker 10 and the object to which the speaker 10 is attached (for example, a panel of a side door of an automobile) to vibrate.

[0063] A second coil 32 of a second driving unit 30 is disposed in a second magnetic gap G2. The second coil 32 is connected to a transmission path. Due to the action of an electric signal from the transmission path and the magnetic field of the second magnetic gap G2, the second bobbin 31 vibrates together with the second coil 32. As a result, the second driving unit 30 including the weight 39 vibrates. The first driving unit 20 and the second driving unit 30 are configured to operate in opposite phases to each other. Therefore, the vibration force generated in response to the vibration of the first driving unit 20 can be canceled, and the vibration of the entire speaker 10 can be suppressed.

[0064] <Function and Effect> Next, the function and effect of the present embodiment will be described.

[0065] In the present embodiment, as shown in FIG. 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, 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 diameter of the second coil 32 is larger than that of the first coil 22. Both the first magnetic gap G1 and the second magnetic gap G2 are open on the upper side which is one side in the axial direction. The second magnetic gap G2 is located on the lower side which is the other side in the axial direction than the first magnetic gap G1.

[0066] Also, in the present 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 through only the second magnetic gap G2 among the first magnetic gap G1 and the second magnetic gap G2. The magnetic circuit 40 includes a cylindrical magnetic member 43 that forms a portion between the outer formation surface G1b of the first magnetic gap G1 and the inner formation surface G2a of the second magnetic gap G2 in the first magnetic path 71, and detour magnetic path forming portions 41, 42, 45 that form a portion between the outer formation surface G2b of the second magnetic gap G2 and the inner formation surface G1a of the first magnetic gap G1 in the first magnetic path 71. And the detour magnetic path forming portions 41, 42, 45 have a first magnetic path magnet 42 that mainly forms the first magnetic path 71. Therefore, the magnetic flux density of the first magnetic gap G1 and the second magnetic gap G2 can be ensured by the first magnetic path magnet 42.

[0067] Also, in the present embodiment, the magnetic circuit 40 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 magnetic flux density of the second magnetic gap G2 can be ensured by the second magnetic path magnet 44.

[0068] Also, in the present embodiment, a space (first space 61) that radially separates the cylindrical magnetic member 43 and the detour magnetic path forming portions 41, 42, 45 is formed below the first magnetic gap G1. For this reason, it becomes difficult to form a magnetic path (third magnetic path) that passes through only the first magnetic gap G1 among 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] Also, in the present embodiment, the first space 61 is a space into which the first coil 22 can enter. Therefore, since the first space 61 can be used as a space into which the first coil 22 can enter, it is easy to miniaturize the speaker 10 in the vertical direction.

[0070] Also, in the present embodiment, the magnet 44 for the second magnetic path is formed of an annular magnet. And, a second space 62 into which the first coil 22 can enter is formed below the first space 61 inside the radial direction of the annular magnet. Therefore, since a space into which the first coil 22 can enter can also be created below the first space 61, it is easy to reduce the size of the speaker 10 in the vertical direction. Note that the inner diameter of the magnet 44 for the second magnetic path may be formed smaller than the inner diameter of the cylindrical portion 43a. Also, the outer formation surface G1b of the first magnetic gap G1 may be made smaller than the inner diameter of the cylindrical portion 43a. In particular, in the present embodiment, since the inner diameter of the cylindrical magnetic member 43 and the inner diameter of the magnet 44 for the second magnetic path are substantially the same, formation of the third magnetic path can be further suppressed, and it becomes easier to secure the magnetic flux density of the first magnetic gap G1 and the second magnetic gap G2.

[0071] Also, in the present embodiment, the detour magnetic path forming portions 41, 42, 45 include an upper magnetic member 41 disposed above the magnet 42 for the first magnetic path, and a lower magnetic member 45 disposed below the magnet 42 for the first magnetic path. Therefore, since the magnet 42 for the first magnetic path is sandwiched between the upper magnetic member 41 and the lower magnetic member 45, a decrease in the magnetic force of the magnet 42 for the first magnetic path can be suppressed.

[0072] Also, in the present 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] Also, in the present embodiment, the magnet 44 for the second magnetic path is formed of an annular magnet. The lower magnetic member 45 has an outer formation surface G2b of the second magnetic gap G2. Therefore, a part (protrusion 45c) of the lower magnetic member 45 passes through the inside in the radial direction of the annular magnet constituting the magnet 44 for the second magnetic path. As a result, the volume of the magnet (annular magnet) constituting the magnet 44 for the second magnetic path can be reduced.

[0074] In addition, in the present embodiment, a concave portion 45e that is recessed upward is formed at the radial center on the lower surface of the lower magnetic member 45. Therefore, the magnetic circuit 40 can be lightened. As a result, the speaker 10 can be lightened.

[0075] In addition, in the present embodiment, the upper end (bottom surface 45e2) of the concave portion 45e is located above the lower surface of the second magnetic path magnet 44. Therefore, the magnetic circuit 40 and the speaker 10 can be further lightened. In particular, in the present embodiment, since the upper end (bottom surface 45e2) of the concave portion 45e is located above the upper surface of the second magnetic path magnet 44, the magnetic circuit 40 and the speaker 10 are significantly lightened.

[0076] In addition, in the present embodiment, as shown in FIG. 1, the first driving unit 20 is a driving unit for emitting sound, and the second driving unit 30 is a driving unit for canceling the vibration of the entire speaker 10 by the first driving unit 20. Therefore, the vibration of the entire speaker 10 can be suppressed.

[0077] (Modification example) Next, with reference to FIG. 3, the magnetic circuit 80 according to the modification example will be described. Note that descriptions of portions common to the magnetic circuit 40 will be omitted as appropriate.

[0078] As shown in FIG. 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 such that their like poles face each other, that is, 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] Among the first magnetic circuit 71, the portion between the outer formation surface G1b of the first magnetic gap G1 and the inner formation surface G2a of the second magnetic gap G2 is formed by the cylindrical magnetic member 83. Among the first magnetic circuit 71, the portion between the outer formation surface G2b of the second magnetic gap G2 and the inner formation surface G1a of the first magnetic gap G1 is formed by 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. 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 supply magnetic flux to the first magnetic circuit 71 and correspond to the "magnet for the first magnetic circuit".

[0082] Among the second magnetic circuit 72, the portion that does not overlap with the first magnetic circuit 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 supplies magnetic flux to the second magnetic circuit 72 and corresponds to the "magnet for the second magnetic circuit". By connecting the cylindrical magnetic member 83 and the detour magnetic path forming portions 81, 82, 84a, 85 by the radially outer portion 84b of the lower magnet 84, a second magnetic circuit 72 that passes through the second magnetic gap G2 and does not pass through the first magnetic gap G1 is formed. The cylindrical magnetic member 83 and the detour magnetic path forming portions 81, 82, 84a, 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 erected 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 portion 83a having a cylindrical shape and an outer protruding portion 83b protruding radially outward from the lower end portion of the cylindrical portion 83a. The inner peripheral surface at the upper end portion of the cylindrical portion 83a functions as the outer formation surface G1b of the first magnetic gap G1. The radially outer surface of the outer protruding portion 83b functions as the inner formation 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 portion 82a and an outer protruding portion 82b protruding radially outward from the upper end portion of the main body portion 82a. The outer peripheral surface of the outer protruding portion 82b of the first magnetic member 82 functions as the inner formation 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 peripheral surface of the cylindrical magnetic member 83 and the outer peripheral surface of the first magnetic member 82. Among this space, the space between the outer peripheral surface of the outer protruding portion 82b of the first magnetic member 82 and the inner peripheral surface of the cylindrical magnetic member 83 becomes the first magnetic gap G1, and the space below the second magnetic gap G2 becomes 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 from the bypass magnetic path forming portions 81, 82, 84a, 85 (specifically, the first magnetic member 82).

[0089] (Other Modification Examples) In the magnetic circuit 80, the radially inner portion 84a and the radially outer portion 84b of the lower magnet 84 may be configured by two mutually divided magnets. That is, the lower magnet 84 may be configured by two magnets, a columnar inner magnet disposed radially inward and an annular outer magnet disposed radially outside the inner magnet. In this case, a space (second space, refer to the 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) and the radially outer portion 84b (outer magnet) of the lower magnet 84.

[0090] As described above, the preferred embodiments of the present disclosure have been described, but the present disclosure is not limited to the above embodiments. The following is a supplementary note for reference.

[0091] In the above embodiment, the first driving unit 20 has a 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 may not have a coupler. That is, 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 embodiment, the magnetic circuits 40 and 80 have flanges 45d and 85d. However, the magnetic circuit of the present disclosure is not limited to this and may not have a flange.

Explanation of Reference Numerals

[0094] 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 the first magnetic circuit 43 Cylindrical magnetic member 44 Magnet for the second magnetic circuit 45 Lower magnetic member 45e Concave portion 45e2 Bottom surface (upper end of the concave portion) 61 First space 62 Second space 71 First magnetic circuit 72 Second magnetic circuit 80 Magnetic circuit 81, 82, 84a, 85 Detour magnetic circuit forming portion 81 First magnet (magnet for the first magnetic circuit) 82 First magnetic member 83 Cylindrical magnetic member 84 Second magnet 84a Radial inner portion (magnet for the first magnetic circuit) 84b Radial outer portion (magnet for the second magnetic circuit) 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 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, 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, A speaker comprising: Both the first magnetic gap and the second magnetic gap are open upward, which is one side in the axial direction, The second magnetic gap is located below on the other side in the axial direction than the first magnetic gap, The magnetic circuit, A first magnetic path passing through both the first magnetic gap and the second magnetic gap, A second magnetic path passing only through the second magnetic gap among the first magnetic gap and the second magnetic gap, and forming, The magnetic circuit, 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, Having a first magnetic path magnet mainly providing magnetic flux to the first magnetic path, and 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, A second magnetic path magnet mainly providing magnetic flux to the second magnetic path, Comprising, A first space that radially separates the cylindrical magnetic member and the detour magnetic path forming portion is formed below the first magnetic gap, Speaker.

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

3. The second magnetic path magnet is composed of an annular magnet, A second space into which the first coil can enter is formed below the first space on the radially inner side of the annular magnet, The speaker according to claim 2.

4. The detour magnetic path forming portion, An upper magnetic member disposed above the first magnetic path magnet, A lower magnetic member disposed below the first magnetic path magnet, Comprising, The speaker according to claim 1.

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

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

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

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

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

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