Sound-emitting member of a speaker and speaker device

Abstract

A speaker device 1 is provided with a center cap 11 including a dome portion 11a formed of a rotated body shape obtained by rotating a quarter elliptic arc Ea in a manner such that when a straight line extending from the quarter elliptic arc Ea to be perpendicular to the long axis Al thereof but different from the short axis As is a rotating axis Ar, the range of the quarter elliptic arc Ea from an intersection P1 with the rotating axis Ar to an intersection P2 with the long axis Al is rotated.

Description

Technical Field

[0001] The present disclosure relates to a sound emitting member of a speaker and a speaker device.

Background Art

[0002] In a cone-type speaker, a center cap is provided at the central portion of a conical diaphragm. The center cap is a dome-shaped sound emitting member that vibrates together with the cone portion, and tends to mainly affect sounds of medium pitch or higher. Also, in a dome-type speaker such as a tweeter, a dome-shaped sound emitting member functions as a main diaphragm.

[0003] For example, Patent Document 1 discloses a cone-type speaker having a bullet-shaped center cap at the central portion of a conical diaphragm. In the speaker of Patent Document 1, since the bullet-shaped center cap has high mechanical strength in the sound pressure radiation direction, the high-frequency resonance frequency moves to a higher frequency range and a sharp peak dip occurs. On the other hand, the bullet-shaped center cap of Patent Document 1 suppresses the peak dip in the high frequency range by making the radius of curvature of the central portion smaller than the radius of curvature of other portions and providing a highly flexible portion in these other portions.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, a bullet-shaped center cap such as that of Patent Document 1 has a long length in the sound pressure radiation direction due to its structure, that is, the overall height of the center cap is increased, which hinders the miniaturization of the speaker. For example, a speaker used in a portable speaker requires a thin center cap, and further improvement in high-frequency characteristics is also desired.

[0006] The present disclosure has been made to solve such problems, and an object thereof is to provide a sound radiating member of a speaker and a speaker device that can achieve both improvement in high-frequency characteristics and thinning.

Means for Solving the Problems

[0007] In order to achieve the above object, the sound radiating member of the speaker according to the present disclosure includes a dome portion having a rotating body shape obtained by rotating a straight line that is perpendicular to the major axis and different from the minor axis on a quarter ellipse arc about a rotation axis, from the intersection with the rotation axis to the intersection with the major axis within the quarter ellipse arc.

[0008] In the above-described sound radiating member of the speaker, a cylindrical portion having the rotation axis as a central axis may be connected to the opening edge of the dome portion.

[0009] In the above-described sound radiating member of the speaker, a flange portion that extends radially with respect to the rotation axis may be provided from the tip edge of the cylindrical portion.

[0010] Further, in order to achieve the above object, the speaker device according to the present disclosure includes the above-described sound radiating member of the speaker and a cylindrical voice coil bobbin that fits into the opening of the sound radiating member.

[0011] In the above-described speaker device, a conical diaphragm connected to the outer peripheral surface of the voice coil bobbin may be further provided.

Advantages of the Invention

[0012] According to the sound-emitting member and the speaker device of the present disclosure using the above means, it is possible to achieve both improvement in high-frequency characteristics and thinning.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0015] (First Embodiment) FIG. 1 is a perspective view of a speaker device 1 according to the first embodiment. FIG. 2 is a side cross-sectional view of the speaker device 1. Hereinafter, the configuration of the speaker device 1 of the first embodiment will be described with reference to these drawings.

[0016] The speaker device 1 of this embodiment is a cone-type speaker equipped with a center cap, and has a vibrating portion 10 and a magnetic circuit portion 20. Hereinafter, in this embodiment, the speaker device 1 will be described with the vibrating portion 10 side on the central axis O1 as the front side and the magnetic circuit portion 20 side as the back side. Sound is radiated from the vibrating portion 10 toward the front side.

[0017] The vibrating portion 10 includes a center cap 11, a cone-shaped diaphragm 12, and an edge portion 13. A center cap 11, which is a dome-shaped sound radiating member, is disposed at the central portion of the vibrating portion 10, and a cone-shaped diaphragm 12 extends radially from the central portion. An edge portion 13 is formed at the outer peripheral edge of the cone-shaped diaphragm 12. The outer peripheral edge of the edge portion 13 is connected to a frame 14. The frame 14 has a cross-sectional concave shape in which the diameter gradually decreases toward the back side, and the back side end portion of the frame 14 is connected to the yoke 21 of the magnetic circuit portion 20.

[0018] The materials of each part in the vibrating portion 10 are not particularly limited. For example, the center cap 11 and the cone-shaped diaphragm 12 can be made of various materials such as paper-based, polymer-based, metal-based, or composite-based materials combining these and ceramic-based materials. Also, the edge portion 13 can be made of a relatively highly elastic polymer-based material such as rubber or resin. In addition, natural fiber-based or synthetic fiber-based materials may be used as the materials of each part in the vibrating portion 10. Furthermore, the base material of each part in the vibrating portion 10 may be coated with a coating such as a rubber coat.

[0019] The frame 14 can be made of a metal-based material. The magnetic circuit portion 20 includes a yoke 21, a first magnet 22, a main plate 23, a second magnet 24, and a top plate 25. Inside the bottomed cylindrical yoke 21, the first magnet 22, the main plate 23, the second magnet 24, and the top plate 25 are laminated along the central axis O1 direction.

[0020] Specifically, the yoke 21 has a disk-shaped bottom portion 21b, a cylindrical portion 21a erected from the periphery of the bottom portion 21b, and a cylindrical convex portion 21c protruding forward from the central portion of the bottom portion 21b. A first magnet 22 having the same diameter as the convex portion 21c is laminated on the top surface (front surface) of the convex portion 21c. A cylindrical main plate 23 having a diameter slightly larger than that of the first magnet 22 is laminated on the first magnet 22. A second magnet 24 having the same diameter as the first magnet 22 is laminated on the main plate 23, and a top plate 25 having the same diameter is further laminated on the second magnet 24. The thicknesses of these members in the direction of the central axis O1 are gradually reduced in the order of the main plate 23, the first magnet 22, the second magnet 24, and the top plate 25. Note that the diameters and thicknesses of the convex portion of the yoke, the first magnet, the main plate, the second magnet, and the top plate are merely examples and are not limited to this shape and dimensions.

[0021] A cylindrical voice coil bobbin 26 extending forward with the central axis O1 as the axis is disposed between the outer peripheral surface of the main plate 23 and the inner peripheral surface of the cylindrical portion 21a of the yoke 21. A voice coil 27 is wound around the outer peripheral surface of the voice coil bobbin 26 at a position facing the outer peripheral surface of the main plate 23. The voice coil bobbin 26 is supported by the frame 14 via an elastic damper 28 and is vibratable in the direction of the central axis O1. Note that a cone-type speaker without the damper 28 may also be used.

[0022] The magnetic circuit portion 20 forms a so-called repulsive magnetic circuit in which the first magnet 22 and the second magnet 24, which are permanent magnets, are arranged such that the like poles face each other, and the voice coil 27 is disposed in the repulsive magnetic field generated on the outer peripheral side of the main plate 23 made of a magnetic material disposed between the two magnets 22 and 24. Although not shown, the voice coil 27 is connected to a signal transmission circuit. Upon receiving a signal from the signal transmission circuit, the voice coil bobbin 26 vibrates together with the voice coil 27, and the vibration is transmitted to the center cap 11 and the conical diaphragm 12 to cause vibration, thereby radiating sound.

[0023] The conical diaphragm 12 of the vibrating part 10 is adhesively bonded to the outer peripheral surface on the front side of the voice coil bobbin 26 with an adhesive, and the center cap 11 is fitted (externally fitted) into the opening on the front side of the voice coil bobbin 26.

[0024] Fig. 3 shows a structural explanatory diagram consisting of a plan view and a side cross-sectional view of the center cap 11. Hereinafter, the center cap 11 will be described in more detail based on the same figure.

[0025] The center cap 11 of the present embodiment is composed of a dome portion 11a, a cylindrical portion 11b, and a flange portion 11c.

[0026] As shown in Fig. 3, the dome portion 11a has a shape of a solid of revolution of a partial elliptical arc. Specifically, the dome portion 11a is formed by rotating a part of the quarter-elliptical arc Ea (hereinafter referred to as the quarter-elliptical arc Ea) obtained by cutting an ellipse E shown by a two-dot chain line in Fig. 3 with the major axis Al (semi-major axis) and the minor axis As (semi-minor axis) shown by solid lines, around a rotation axis Ar parallel to the minor axis As. The rotation axis Ar is a straight line parallel to the minor axis As passing through a position shifted (offset) from the intersection (origin) of the minor axis As and the major axis Al toward the tip side of the major axis (the direction of shortening the major axis). Then, in the quarter-elliptical arc Ea, the solid of revolution shape of the dome portion 11a is formed by rotating the partial elliptical arc between the intersection point P1 with the rotation axis Ar and the intersection point P2 with the major axis Al around the rotation axis Ar, and the hatched portion in Fig. 3 becomes the internal space of the dome portion 11a.

[0027] That is, the dome portion 11a is a rotating body formed by rotating a straight line that is perpendicular to the major axis Al and different from the minor axis As on the quarter-elliptical arc Ea around the rotation axis Ar, from the intersection point P1 with the rotation axis Ar to the intersection point P2 with the major axis Al within the quarter-elliptical arc Ea. When the dome portion 11a configured in this way is attached to the speaker device 1, it is arranged such that the rotation axis Ar coincides with the central axis O1. And the apex of the dome portion 11a is the intersection point P1 of the quarter-elliptical arc Ea and the rotation axis Ar, and the apex has a slightly pointed shape. Note that the height H from the opening to the apex on the central axis O1 of the dome portion 11a, that is, the length of the rotation axis Ar, is preferably shorter than the opening radius R, and the rotation axis Ar is located closer to the minor axis As than the center on the major axis Al of the quarter-elliptical arc Ea.

[0028] Also, the cylindrical portion 11b is a cylindrical portion that is connected to the opening edge of the dome portion 11a and has the rotation axis Ar as its central axis. The opening edge of the dome portion 11a is the intersection point P2 with the major axis Al on the quarter-elliptical arc Ea, and the cylindrical portion 11b extending along the rotation axis Ar direction from the opening edge extends in the normal direction of the opening edge of the dome portion 11a. Therefore, the cylindrical portion 11b is smoothly connected to the opening edge of the dome portion 11a without generating an inflection point.

[0029] The flange portion 11c is an enlarged diameter portion that expands radially with respect to the rotation axis Ar from the tip edge of the cylindrical portion 11b. Specifically, the flange portion 11c extends further toward the back side from the tip edge of the cylindrical portion 11b and smoothly curves radially outward. Note that the outer peripheral edge of the flange portion may be further curved upward.

[0030] The center cap 11 configured as described above is placed over the opening of the voice coil bobbin 26, and the inner peripheral surface of the cylindrical portion 11b and the outer peripheral surface of the opening edge of the voice coil bobbin 26 are adhered. That is, the adhesion surface between the center cap 11 and the voice coil bobbin 26 is parallel to the vibration direction. Further, as shown in FIG. 2, the adhesion portion between this center cap 11 and the voice coil bobbin 26 is separated from the adhesion portion between the cone-shaped diaphragm 12 and the voice coil bobbin 26, and the center cap 11 and the cone-shaped diaphragm 12 are not in direct contact. By not being in direct contact in this way, there is an advantage that the vibrations of the center cap 11 and the cone-shaped diaphragm 12 do not interfere with each other. On the other hand, it is not limited to this configuration, and a configuration in which the center cap and the cone-shaped diaphragm are in contact may be adopted.

[0031] FIG. 4 is a graph showing the frequency characteristics of the speaker device 1 according to the first embodiment and the speaker device of the first comparative example in (a), and a partial side cross-sectional view of the center cap of the first comparative example in (b). FIG. 5 is a graph showing the frequency characteristics based on the simulation results of the speaker device 1 according to the first embodiment and the speaker device of the second comparative example in (a), and a partial side cross-sectional view of the center cap of the second comparative example in (b). Hereinafter, the operation and effects of the speaker device 1 including the sound emitting member of the first embodiment will be described based on these figures.

[0032] In FIG. 4(a), the horizontal axis represents the frequency (unit: Hz), and the vertical axis represents the output sound pressure level of the speaker (unit: dB). The characteristics of the speaker device 1 of the first embodiment are shown by a solid line, and the characteristics of the speaker device of the first comparative example are shown by a dotted line.

[0033] The speaker device 1 of the present embodiment and the speaker device of the first comparative example differ only in the center cap. The center cap 101 of the first comparative example has a dome shape as shown in Fig. 4(b). In the side cross-section of the center cap 101 of the first comparative example, the top surface portion 101a has an arc shape with a constant curvature, and a conical surface 101b that expands radially outward is formed from the periphery of the top surface portion 101a toward the opening side (rear side). From the open end of the conical surface 101b, it has a flange portion 101c that is folded back to the front side. In this center cap 101 of the first comparative example, the flange portion 101c is adhered to the cone-shaped diaphragm and attached. Note that the center cap 11 of the speaker device 1 of the first embodiment having the characteristics shown in Fig. 4(a) is made of aluminum, and the center cap 101 of the first comparative example is made of a polymer (resin) film.

[0034] In the speaker device of the first comparative example shown by the dotted line in Fig. 4(a), a peak occurs around 10 kHz on the high-frequency side, and a dip occurs around 12.5 kHz, and the high-frequency characteristics are non-uniform. In contrast, in the speaker device 1 of the first embodiment shown by the solid line in Fig. 4(a), the peak around 10 kHz in the comparative example disappears, the dip around 12.5 kHz is also suppressed, and it can be seen that the high-frequency characteristics are made uniform.

[0035] Fig. 5(a) shows the frequency (unit: Hz) on the horizontal axis and the output sound pressure level of the speaker (unit: dB) on the vertical axis. The characteristics of the speaker device 1 of the first embodiment are shown by the solid line, and the characteristics of the speaker device of the second comparative example are shown by the dotted line.

[0036] The speaker device 1 of the present embodiment and the speaker device of the second comparative example differ only in the center cap. The center cap 201 of the second comparative example has a dome shape as shown in FIG. 5(b). In the side cross section of the center cap 201 of the second comparative example, the entire dome portion 201a forms an arc shape with a constant curvature, and a flange portion 201b folded back to the front side extends from the open end of the dome portion 201a. In this center cap 201 of the second comparative example, the flange portion 201b is adhered to and attached to the cone diaphragm. Note that the center cap 11 of the speaker device 1 of the first embodiment having the characteristics shown in FIG. 5(a) is made of aluminum, and the center cap 201 of the second comparative example is also made of aluminum.

[0037] In the speaker device of the second comparative example indicated by the dotted line in FIG. 5(a), a peak occurs around 10 kHz on the high-frequency side, and a dip occurs around 15 kHz, resulting in non-uniform high-frequency characteristics. On the other hand, in the speaker device 1 of the first embodiment indicated by the solid line in FIG. 5(a), the peak around 10 kHz in the second comparative example disappears, and the dip around 15 kHz is also suppressed while moving to around 12.5 kHz, indicating that the high-frequency characteristics are made uniform.

[0038] As described above, in the speaker device 1 of the present embodiment, the dome portion 11a of the center cap 11 has a shape of a partial elliptical arc rotating body, and by shortening the length in the direction of the central axis O1 and slightly sharpening the apex, the shape rigidity can be improved.

[0039] In addition, since the center caps 101 and 201 of the first and second comparative examples are attached to the diaphragm, vibrations are transmitted from the voice coil to the center caps 101 and 201 via the diaphragm. Further, the center cap 101 of the first comparative example has an inflection point in the dome portion. On the other hand, the center cap 11 of the present embodiment has no inflection point from the apex to the opening edge in the dome portion 11a, and further has a shape that is continuously connected to the cylindrical portion 11b at the opening edge without an inflection point. Further, since the cylindrical portion 11b extending in parallel with the vibration direction of the voice coil bobbin 26 is formed, the transmission efficiency from the voice coil bobbin 26 can be improved as compared with the center caps 101 and 201 of the comparative examples while increasing the rigidity of the center cap 11. Therefore, the split resonance of the center cap 11 can be prevented, and the high-frequency characteristics can be improved as shown in FIGS. 4(a) and 5(a).

[0040] Furthermore, since the center cap 11 is formed with a flange portion 11c that smoothly curves radially outward at the leading edge of the cylindrical portion 11b, the flange portion 11c functions as a guide when the center cap 11 is attached to the voice coil bobbin 26. Therefore, the center cap 11 can be easily fitted to the voice coil bobbin 26, and the attachment workability of the center cap 11 can be improved.

[0041] As described above, the center cap 11 of the first embodiment can achieve both improvement of high-frequency characteristics and thinning, and the speaker device 1 including the center cap 11 can also achieve both improvement of high-frequency characteristics and thinning.

[0042] (Second Embodiment) The speaker device 1 of the first embodiment described above is a cone-type speaker, but the speaker to which the sound-emitting member of the present invention can be applied is not limited to this, and can also be applied to a dome-type speaker such as a tweeter, for example.

[0043] FIG. 6 is a perspective view of the speaker device 2 according to the second embodiment, and FIG. 7 is a side sectional view of the speaker device 2. Hereinafter, the speaker device 2 of the second embodiment will be described based on these figures.

[0044] The speaker device 2 of the second embodiment is a dome-shaped speaker and has a vibrating portion 30 and a magnetic circuit portion 40. Hereinafter, in the speaker device 2, the side of the vibrating portion 30 on the central axis O2 will be described as the front side, and the side of the magnetic circuit portion 40 will be described as the back side. Sound is radiated from the vibrating portion 30 toward the front side.

[0045] The vibrating portion 30 includes a dome-shaped diaphragm 31 and an edge portion 32, and the edge portion 32 is connected to the periphery of the dome-shaped diaphragm 31. The outer peripheral edge of the edge portion 32 is sandwiched and fixed by a first frame 53 and a second frame 54.

[0046] The dome-shaped diaphragm 31 is a sound radiating member similar to the center cap 11 of the first embodiment, and is composed of a dome portion 31a, a cylindrical portion 31b, and a flange portion 31c. The configuration of each part is the same as that of the first embodiment, and the description thereof will be omitted. However, in the dome-shaped diaphragm 31 of the second embodiment, the edge portion 32 is adhered from the outer peripheral portion of the cylindrical portion 31b to the flange portion 31c.

[0047] The magnetic circuit portion 40 has a magnet 42 and a plate 43 laminated inside a bottomed cylindrical yoke 41, and a cylindrical voice coil bobbin 45 around which a voice coil 44 is wound is disposed between the plate 43 and the yoke 41.

[0048] The voice coil bobbin 45 extends in the direction of the central axis O2, and the outer peripheral surface on the front side is fitted and adhered to the inner peripheral surface of the cylindrical portion 31b of the dome-shaped diaphragm 31. Although not shown, the voice coil 44 is connected to a signal transmission circuit, and receives a signal from the signal transmission circuit to vibrate the voice coil bobbin 45 together with the voice coil 44, and the vibration is transmitted to the dome-shaped diaphragm 31 to radiate sound.

[0049] In the speaker device 2 of the second embodiment configured as described above, since the dome portion 31a of the dome-shaped diaphragm 31 has a partial elliptical arc-shaped rotating body shape, it is possible to improve the shape rigidity while shortening the length in the direction of the central axis O2. In addition, the same effects as those of the first embodiment can be achieved. The dome-shaped diaphragm 31 of the second embodiment can achieve both high-frequency characteristic improvement and thinning, and the speaker device 2 provided with the dome-shaped diaphragm 31 can also achieve both high-frequency characteristic improvement and thinning.

[0050] With the above, the description of the first and second embodiments of the present disclosure is completed, but the aspects of the present disclosure are not limited to these embodiments.

[0051] For example, the configuration of the magnetic circuit portion is not limited to the above embodiment, and other configurations of the magnetic circuit portion may be used.

Explanation of Reference Numerals

[0052] 1, 2 Speaker device 10, 30 Vibration portion 11 Center cap (sound emitting member) 11a, 31a Dome portion 11b, 31b Cylindrical portion 11c, 31c Flange portion 12 Cone-shaped diaphragm 13, 32 Edge portion 14 Frame 20, 40 Magnetic circuit portion 21, 41 Yoke 22 First magnet 23 Main plate 24 Second magnet 25 Top plate 26, 45 Voice coil bobbin 27, 44 Voice coil 28 Damper 31 Dome-shaped diaphragm (sound emitting member) 53 First frame 54 Second frame 42 Magnet 43 Plate

Claims

1. A sound radiating member of a speaker including a dome portion having a rotating body shape obtained by rotating, on a quarter elliptical arc, a straight line perpendicular to the major axis and different from the minor axis as a rotation axis, within a range from the intersection with the rotation axis to the intersection with the major axis among the quarter elliptical arc.

2. The sound radiating member of the speaker according to Claim 1, having a cylindrical portion with the rotation axis as a central axis, connected to an opening edge of the dome portion.

3. The sound radiating member of the speaker according to Claim 2, having a flange portion extending radially with respect to the rotation axis from a leading edge of the cylindrical portion.

4. A sound radiating member of the speaker according to any one of Claims 1 to 3, a cylindrical voice coil bobbin fitted into an opening of the sound radiating member, and a speaker device comprising the same.

5. The speaker device according to Claim 4, further comprising a conical diaphragm connected to an outer peripheral surface of the voice coil bobbin.

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