Exciter

Abstract

An exciter (1) includes a vibrator (2) including a yoke and a magnet, a frame (3) incorporating the vibrator (2) with a damper (4) therebetween, and a voice coil bobbin (5) disposed inside the frame (3) and having another end (5b) that extends to near the vibrator (2) and is provided with a voice coil (11). The frame (3) has an opening (3b), and the voice coil bobbin (5) is mounted on the edge of the opening (3b). One end (5a) of the voice coil bobbin (5) is opened to the outside of the frame (3). The voice coil bobbin (5) is provided with a vibrating member (10) that covers the opened portion.

Claims

1. An exciter comprising: a vibrator comprising a yoke and a magnet; a frame incorporating the vibrator so as to support the vibrator through a damper in such a manner that the vibrator can vibrate; and a cylindrical voice coil bobbin disposed in the frame and having one end mounted on the frame and another end extending to near the vibrator, the another end being provided with a voice coil, wherein the exciter can output a sound through a transmission medium having the frame disposed thereon when the vibrator vibrates in response to an acoustic signal flowing through the voice coil and vibration of the vibrator is transmitted to the frame through the damper, a ceiling surface of the frame has an opening, an outer circumferential surface of the one end of the voice coil bobbin is laterally fixed to and mounted on an edge of the opening provided in the ceiling surface of the frame in such a manner that inside of the cylindrical voice coil bobbin is opened to outside of the frame from the opening, and a vibrating member is disposed so as to cover an opened portion of the one end of the voice coil bobbin.

2. The exciter according to claim 1, wherein an outer surface of the frame is covered by a sound absorber.

3. The exciter according to claim 1, wherein the edge of the opening is provided with a damping member, and the voice coil bobbin is mounted to the edge of the opening through the damping member.

4. The exciter according to claim 1, wherein the voice coil bobbin is provided with a heat dissipating member for dissipating heat accumulated in an internal space of the frame through the voice coil bobbin.

5. The exciter according to claim 1, wherein the frame has a bottom opposite to the ceiling surface in a height direction of the exciter such that an entirety of the vibrator is provided between the ceiling surface and the bottom in the height direction.

6. An exciter comprising: a vibrator comprising a yoke and a magnet; a frame incorporating the vibrator so as to support the vibrator through a damper in such a manner that the vibrator can vibrate; and a cylindrical voice coil bobbin disposed in the frame and having one end mounted on the frame and another end extending to near the vibrator, the another end being provided with a voice coil, wherein the exciter can output a sound through a transmission medium having the frame disposed thereon when the vibrator vibrates in response to an acoustic signal flowing through the voice coil and vibration of the vibrator is transmitted to the frame through the damper, the frame has an opening, an outer circumferential surface of the one end of the voice coil bobbin is mounted on an edge of the opening in such a manner that inside of the cylindrical voice coil bobbin is opened to outside of the frame from the opening, a vibrating member is disposed so as to cover an opened portion of the one end of the voice coil bobbin, and an outer surface of the frame is covered by a sound absorber.

7. An exciter comprising: a vibrator comprising a yoke and a magnet; a frame incorporating the vibrator so as to support the vibrator through a damper in such a manner that the vibrator can vibrate; and a cylindrical voice coil bobbin disposed in the frame and having one end mounted on the frame and another end extending to near the vibrator, the another end being provided with a voice coil, wherein the exciter can output a sound through a transmission medium having the frame disposed thereon when the vibrator vibrates in response to an acoustic signal flowing through the voice coil and vibration of the vibrator is transmitted to the frame through the damper, the frame has an opening, an outer circumferential surface of the one end of the voice coil bobbin is mounted on an edge of the opening in such a manner that inside of the cylindrical voice coil bobbin is opened to outside of the frame from the opening, a vibrating member is disposed so as to cover an opened portion of the one end of the voice coil bobbin, and the voice coil bobbin is provided with a heat dissipating member for dissipating heat accumulated in an internal space of the frame through the voice coil bobbin.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a side sectional view showing an exciter of a first embodiment;

(2) FIG. 2 is a diagram showing an example in which the exciter of the first embodiment is installed on a table;

(3) FIG. 3 is a side sectional view showing an exciter of a second embodiment;

(4) FIG. 4 is a side sectional view showing an exciter of a third embodiment;

(5) FIG. 5 is a side sectional view showing a schematic configuration of a cone speaker;

(6) FIG. 6 is a side sectional view showing an example in which a conventional known exciter is installed on a flat plate; and

(7) FIG. 7 is a perspective view showing the rear side of the exciter shown in FIG. 6.

DESCRIPTION OF EMBODIMENTS

(8) Now, an exciter of the present invention will be described in detail using examples thereof.

First Embodiment

(9) FIG. 1 is a side sectional view showing a schematic configuration of an exciter of a first embodiment. In the description below, elements having the same functions as those of the exciter 200 described above are given the same reference signs.

(10) As shown in FIG. 1, an exciter 1 of the first embodiment includes a vibrator 2, a frame 3, a damper 4, a voice coil bobbin 5, and a vibrating member 10. The frame 3 is an approximately cylindrical hollow body having, in a ceiling surface 3a, an opening 3b corresponding to the outer diameter of the voice coil bobbin 5. A lower cylindrical part 3d of the frame 3 has a larger width than an upper cylindrical part 3c thereof. The frame 3 has a step 3e approximately in the center of the outer circumference thereof.

(11) The outer circumferential surface and outer ceiling surface of the frame 3 (the outer surfaces of the frame 3) are covered by a sound absorber 8. The sound absorber 8 has a function of suppressing (attenuating) unwanted vibration or the like (hereafter referred to as unwanted components) transmitted from the inside to the surface of the frame 3. The sound absorber 8 may be a vibration absorber such as urethane. The sound absorber 8 may also be a damping material obtained by bonding butyl rubber or the like to an aluminum sheet for suppressing vibration itself.

(12) A step 3f corresponding to the step 3e on the outer circumference is formed approximately in the center inside the frame 3. The step 3f has the damper 4 mounted thereon. The damper 4 has a structure similar to that of a damper 207 shown in FIG. 7. The damper 4 consists of multiple legs approximately in the shape of S. One end of each approximately S-shaped leg is connected to the step 3f of the frame 3, and the other end thereof is connected to the side of the vibrator 2. The damper 4 is formed of an elastic plate member. The use of the approximately S-shaped legs allows the vibration of the vibrator 2 to be transmitted to the frame 3 while preventing a reduction in the vibration as much as possible.

(13) The vibrator 2 mostly consists of the first yoke 201, the disc-shaped magnet 202, and the second yoke 203 described with reference to FIG. 6. The first yoke 201 is in the shape of a cylinder having a bottom. The disc-shaped magnet 202 is stacked in the center of the inner bottom of the first yoke 201. The second yoke 203 is stacked on the disc-shaped magnet 202. As with the disc-shaped magnet 202, the second yoke 203 has a disc-shaped flat surface. The diameter of the second yoke 203 is slightly larger than that of the disc-shaped magnet 202. The inner diameter of the cylindrical first yoke 201 is larger than the diameters of the disc-shaped magnet 202 and second yoke 203. Gaps are formed between the inner surface 201a of the first yoke 201 and the outer surfaces of the disc-shaped magnet 202 and second yoke 203 facing the inner surface 201a. Due to the configuration of the vibrator 2 described above, the damper 4 is mounted to the side 201b of the first yoke 201.

(14) The voice coil bobbin 5 is mounted on the edge of the opening 3b formed in the ceiling surface 3a of the frame 3. Specifically, the outer circumferential surface of an end 5a of the voice coil bobbin 5 and the edge of the opening 3b of the frame 3 are in contact with each other. The outer circumferential surface of the voice coil bobbin 5 is laterally fixed to the edge of the opening 3b of the frame 3. By fixing the voice coil bobbin 5 to the frame 3 in this manner, the cylindrical voice coil bobbin 5 is mounted in such a manner that the inside thereof is opened to the outside of the frame 3 from the opening 3b.

(15) The voice coil bobbin 5 is fixed in such a manner that the end 5a thereof protrudes slightly upward from the upper surface of the ceiling of the frame 3. The vibrating member 10 for use in the dome of a high-frequency speaker (tweeter) or the like is mounted on the protruding end 5a of the voice coil bobbin 5. The vibrating member 10 is formed of, for example, silk in the shape of a dome. The vibrating member 10 is mounted so as to cover the opened portion of the voice coil bobbin 5.

(16) The other end, 5b, of the voice coil bobbin 5 is disposed directly below the end 5a and extends into the gaps between the inner surface 201a of the first yoke 201 and the outer surfaces of the disc-shaped magnet 202 and second yoke 203. The outer circumferential surface of the extending other end, 5b, of the voice coil bobbin 5 facing the inner surface 201a of the first yoke 201 is provided with a voice coil 11.

(17) FIG. 2 shows an example in which the exciter 1 is installed on a table 13. The bottom 3g of the frame 3 of the exciter 1 is fixed to a surface 13a of the table 13 using, for example, a double-sided tape. An acoustic signal reproducing device (e.g., a CD player) 14 having an amplification function is installed, for example, in a position slightly distant from the exciter 1 on the surface 13a. An output of the acoustic signal reproducing device 14 and an end of the signal cable of the voice coil 11 are electrically connected through a speaker cable 15. With the exciter 1 installed on the surface 13a of the table 13 in this manner, the acoustic signal reproducing device 14 outputs an acoustic signal to the voice coil 11. When the voice coil 11 receives the acoustic signal, the voice coil bobbin 5 vibrates vertically (reciprocates in the direction in which it extends) due to the conduction of the acoustic signal by the voice coil 11 and a magnetic field generated by the disc-shaped magnet 202. The vibrator 2 also vibrates vertically.

(18) Due to the vertical vibration of the vibrator 2, the vibration of the acoustic signal is transmitted to the frame 3 through the damper 4. The vibration transmitted to the frame 3 is transmitted to the entire surface 13a through the bottom 3g of the frame 3. Thus, the entire table 13 outputs a sound as a transmission member (transmission medium).

(19) The vertical vibration of the voice coil bobbin 5 vibrates the vibrating member 10, such as silk, mounted on the end 5a of the voice coil bobbin 5. Thus, the acoustic signal (electrical signal) is converted into air vibration (physical vibration), and a sound is outputted (generated) through the vibrating member 10. Since the vibrating member 10 is formed of silk or the like, which is used in the dome of a high-frequency speaker, it can output a fine-grained, high-frequency sound, which is difficult to output or reproduce on the surface 13a, on the basis of the vibration of the vibrator 2 of the exciter 1.

(20) Further, the outer circumferential surface and outer ceiling surface of the frame 3 are covered by the sound absorber 8. Thus, even when the vibration of the voice coil bobbin 5 is transmitted to the frame 3 through the edge of the opening 3b, the occurrence of noise based on unwanted components on the outer surfaces of the frame 3 can be suppressed. This can prevent the output of noise based on unwanted components from the surface of the frame 3 and thus can improve the quality of the output sound of the exciter 1.

(21) As described above, the exciter 1 of the first embodiment can output a high-frequency sound with high quality thanks to the vibrating member 10 disposed on the end 5a of the voice coil bobbin 5, as does a high-frequency cone speaker. Also, the exciter 1 transmits the vibration of the vibrator 2 to the table 13 through the bottom 3g of the frame 3 and thus can output low/mid-frequency sounds more effectively. As seen above, the use of the exciter 1 of the first embodiment allows high-quality, low-to high-frequency sounds to be outputted in balance.

(22) Further, the exciter 1 of the first embodiment can output a fine-grained, high-frequency sound, which is difficult to output or reproduce using a conventional exciter, without having to additionally provide a high-frequency speaker (tweeter) or the like. Thus, it is possible to produce an effect of preventing a cost increase associated with the installation of a high-frequency speaker or the like and eliminating the need to consider the securing of the installation space, or the like.

(23) While the example in which silk or the like is used as the vibrating member 10 of the exciter 1 has been described above, a metal material such as aluminum may be used as the material of the vibrating member 10. The use of aluminum as the vibrating member 10 allows sound quality specific to aluminum to be obtained, as well as allows heat accumulated around the voice coil bobbin 5 to be released (dissipated) through the vibrating member 10 formed of aluminum.

(24) To further improve heat dissipation performance, it is preferred to use a high heat-dissipation material, such as aluminum, as the vibrating member 10, as well as to use a high heat-dissipation material, such as aluminum, as the voice coil bobbin 5. For example, aluminum sheets having high heat dissipation characteristics may be used as the voice coil bobbin 5 and vibrating member 10. If aluminum sheets are used, it is possible to effectively dissipate heat accumulated around the voice coil bobbin 5 (more specifically, inside the frame 3) when the exciter 1 is outputting a sound, by transferring the heat to the vibrating member 10.

Second Embodiment

(25) Next, an exciter of a second embodiment will be described. Elements having the same functions as those of the exciter 1 of the first embodiment are given the same reference signs and will not be described in detail.

(26) FIG. 3 is a side sectional view showing an example of the exciter of the second embodiment. As shown in FIG. 3, in an exciter 20 of the second embodiment, a damping member 21 for absorbing the vibration of the voice coil bobbin 5 is disposed on the edge of the opening 3b formed in the ceiling surface 3a of the frame 3. The voice coil bobbin 5 is mounted to the damping member 21.

(27) As seen above, the exciter 20 of the second embodiment differs from the exciter 1 of the first embodiment in that the voice coil bobbin 5 is mounted to the frame 3 through the damping member 21. The exciter 20 of the second embodiment also differs from the exciter 1 of the first embodiment in that a sound absorber 8 is not mounted on the outer circumferential surface and outer ceiling surface of the frame 3.

(28) As shown in FIG. 3, in the exciter 20 of the second embodiment, the voice coil bobbin 5 is mounted to the frame 3 through the damping member 21 formed of a rubber member or the like. This can prevent the micro-vibration of the voice coil bobbin 5 from being transmitted to the frame 3 through the edge of the opening 3b and thus can prevent noise based on unwanted components from occurring on the surface of the frame 3 or the like due to the micro-vibration of the voice coil bobbin 5. As a result, the quality of an output sound of the exciter 20 can be improved.

(29) Further, the damping member 21 can prevent unwanted components from being transmitted to the frame 3. This eliminates the need to mount a sound absorber 8 on the outer circumferential surface and outer ceiling surface of the frame 3 and thus allows for the simplification of the structure and a reduction in cost.

Third Embodiment

(30) Next, an exciter of a third embodiment will be described. Elements having the same functions as those of the exciter 1 or 20 of the first or second embodiment are given the same reference signs and will not be described in detail.

(31) FIG. 4 is a side sectional view showing an example of the exciter of the third embodiment. As shown in FIG. 4, an exciter 30 of the third embodiment has a structure in which an annular heat dissipating member 31 is disposed around the center of the outer circumferential surface of a voice coil bobbin 5. As seen above, the exciter 30 of the third embodiment differs from the exciters 1, 20 of the first and second embodiments in that the heat dissipating member 31 is disposed on the voice coil bobbin 5.

(32) It is preferred to use a material that does not hamper the vibration of the voice coil bobbin 5, as the heat dissipating member 31 disposed on the voice coil bobbin 5. For example, a light-weight, high-heat dissipation member, such as an aluminum sheet, is preferably used as the heat dissipating member 31.

(33) As shown in FIG. 4, the voice coil bobbin 5 is mounted to the frame 3 through the damping member 21. Thus, the vibration of the voice coil bobbin 5 itself is significantly restricted compared to a cone speaker. For example, there is a problem that heat is more likely to be accumulated in a space between the outer circumferential surface of the voice coil bobbin 5 and the inner surface of the frame 3. For this reason, the heat dissipating member 31 is disposed around the center of the outer circumferential surface of the voice coil bobbin 5 in the space between the voice coil bobbin 5 and frame 3. Thus, the heat dissipation performance of the inside of the exciter 30 can be improved.

(34) To improve heat dissipation performance, it is preferred to dispose the heat dissipating member 31, as well as to use a high heat dissipation material as the voice coil bobbin 5 as described above. For example, if an aluminum sheet is used as the heat dissipating member 31, heat can be dissipated effectively by using aluminum also as the voice coil bobbin 5.

(35) As described above, the exciters of the first to third embodiments include the hollow frame 3 having the bottom 3g for contacting the table 13 or the like (a transmission medium for outputting a sound) and having the opening 3b in the ceiling surface 3a. The vibrator 2 including the first yoke 201, disc-shaped magnet 202 and second yoke 203 is mounted to the inside of the frame 3 through the damper 4 so as to be capable of vibration. Thus, vibration associated with an acoustic signal can be transmitted to the table 13 or the like through the bottom 3g. As a result, the use of the exciters of the first to third embodiments allows the entire surface 13a of the table 13 to output low-to-high full frequency sounds.

(36) The end 5a of the voice coil bobbin 5 is mounted on the opening 3b of the frame 3. The dome-shaped vibrating member 10 is disposed so as to cover the opened portion of the end 5a of the voice coil bobbin 5. The other end 5b of the voice coil bobbin 5 extends to near the second yoke 203, and the voice coil 11 is disposed on the outer circumferential surface of the other end 5b. Owing to this configuration, a high-frequency sound can be outputted by vibrating the vibrating member 10. In particular, silk or the like, which is used in the dome of a high-frequency speaker or the like, is used as the vibrating member 10. Thus, it is possible to output and reproduce a fine-grained, high-frequency sound, which is difficult to output or reproduce with only the vibration of the vibrator 2.

(37) In the exciter 1 of the first embodiment, the outer circumferential surface and outer ceiling surface of the frame 3 (the outer surfaces of the frame 3) are covered by the sound absorber 8. This can prevent the micro-vibration of the voice coil bobbin 5 from being transmitted to the frame 3 and thus noise from occurring from the surface of the frame 3 or the like.

(38) In the exciters 20, 30 of the second and third embodiments, the voice coil bobbin 5 is mounted to the frame 3 through the damping member 21 formed of a rubber member or the like. This can prevent the micro-vibration of the voice coil bobbin 5 from being transmitted to the frame 3 through the edge of the opening 3b and thus can prevent noise from occurring from the surface of the frame 3 or the like.

(39) In the exciter 30 of the third embodiment, the heat dissipating member 31 is disposed around the center of the outer circumferential surface of the voice coil bobbin 5. Thus, the heat dissipation performance of the exciter 30 (voice coil bobbin 5) can be improved.

(40) While the exciter of the present invention has been described in detail with reference to the drawings, the exciter of the present invention is not limited to the examples given in the first to third embodiments. It is apparent that those skilled in the art can conceive of various changes or modifications thereto without departing from the scope set forth in the claims.

(41) For example, the configuration in which the heat dissipating member 31 is disposed in the exciter 20 of the second embodiment has been described as the exciter 30 of the third embodiment. However, the heat dissipating member 31 is not limited to be disposed only in the exciter 20 of the second embodiment. For example, the heat dissipating member 31 may be disposed in the exciter 1 of the first embodiment. Even if the heat dissipating member 31 is disposed in the exciter 1 of the first embodiment, the heat dissipation performance of the exciter 1 (voice coil bobbin 5) can be improved, as seen in the exciter 30 of the third embodiment.

REFERENCE SIGNS LIST

(42) 1, 20, 30, 200 exciter 2 vibrator 3, 104, 205 frame 4, 105, 207 damper 5, 106, 210 voice coil bobbin 3a ceiling surface (of frame) 3b opening (of frame) 3c upper cylindrical part (of frame) 3d lower cylindrical part (of frame) 3e, 3f step (of frame) 3g bottom (of frame) 5a, 210a end (of voice coil bobbin) 5b, 210b other end (of voice coil bobbin) 8 sound absorber 10 vibrating member 11, 110, 211 voice coil 13 table (transmission medium) 13a surface of table 14 acoustic signal reproducing device 15 speaker cable 21 damping member 31 heat dissipating member 100 cone speaker 101, 201 first yoke 101a bottom (of first yoke) 101b cylinder (of first yoke) 102 ring magnet 102a opening (of ring magnet) 103, 203 second yoke 103a opening (of second yoke) 103b open surface (of second yoke) 104a edge (of frame) 104b opening (of frame) 106a end (of voice coil bobbin) 106b end (of voice coil bobbin) 107 edge 108 cone 109 dome 201a inner surface (of first yoke) 201b side (of first yoke) 202 disc-shaped magnet 205a ceiling surface (of frame) 205b lower end (of frame) 207a one end (of damper) 207b other end (of damper) 207c multiple legs (of damper) 214 high-frequency speaker 220 flat plate