JP2008147732A - Bone conduction speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bone conduction speaker which can be made small in size and light in weight while maintaining efficiency of bone conduction, can simplify manufacturing stages, and can reduce the manufacturing cost. <P>SOLUTION: The bone conduction speaker is composed of: a case base 2 where a recessed portion 25 having a nearly circular bottom surface 20 is formed; a voice coil 3 put in the recessed portion 25; a diaphragm 4 which is fitted to a fixation portion 22 constituting an internal wall 23 of the recessed portion 25 of the case base 2 and laid over the voice coil 3 put in the recessed portion 25; a magnet 5 fitted at a nearly center position 40 on the top surface side of the diaphragm 4; and a cover 7 fitted onto the case base 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bone conduction speaker. More specifically, the present invention relates to a bone conduction speaker that can be reduced in size and weight while maintaining the efficiency of bone conduction, and can reduce the manufacturing cost.

  Usually, sound vibrations transmitted by sound waves are transmitted to the eardrum in the ear. There are three bones (ear ossicles) in the eardrum, and the vibration of the eardrum is transmitted to the cochlea like a screw through this bone. The cochlea has limba fluid, and the vibration of this lymph fluid is transmitted to the auditory nerve while turning into an electrical signal, and the brain recognizes the sound. On the other hand, bone conduction omits the process in which the vibration in the above mechanism passes through the eardrum and the ossicle. That is, sound vibrations are sent directly to the cochlea through the skull, and even hearing-impaired people with abnormalities in the eardrum or ear ossicles can hear the sound reliably through this bone conduction if the cochlea and auditory nerve are normal. it can. A speaker applying this principle is a bone conduction speaker (see, for example, Patent Document 1).

  Although a wide variety of bone conduction speakers have been developed, the conventional one is composed of a case base, a yoke, a magnet, a voice coil, and a vibration member. Most vibration members have a form in which a large number of plates are stacked on top of each other, and the magnets are arranged side by side on the side of the voice coil. Therefore, the conventional bone conduction speaker has a problem that it is wider and heavier than ordinary headphones and earphones. In addition, with such a structure, there is a problem that the manufacturing process is complicated and expensive, and the unit price is high.

  In particular, in recent years, bone conduction speakers have been required to be smaller and lighter so that they can be used by attaching them to mobile phones and MP3 players. However, at present, they are smaller and lighter without reducing the efficiency of bone conduction. The reality is that nothing has been realized.

JP 2003-340370 A

  Therefore, in view of the above-mentioned situation, the present invention intends to solve the problem that it is possible to reduce the size and weight while maintaining the efficiency of bone conduction, simplify the manufacturing process, and reduce the manufacturing cost. The point is to provide a bone conduction speaker.

  In order to solve the above-mentioned problems, the present invention comprises a case base in which a recess having a substantially circular bottom surface is formed, a voice coil housed in the recess, and an inner wall of the recess in the case base. A diaphragm attached to the fixed portion that extends over the voice coil housed in the recess, a magnet attached to a substantially central position on the upper surface side of the diaphragm, and an upper portion of the case base The bone conduction speaker characterized by having comprised the lid body attached and comprising was comprised.

  Here, it is preferable that a pole screw projecting upward from a substantially central portion of the bottom surface of the recess is provided integrally with the case base, and the voice coil is disposed around the pole screw, specifically, the pole screw is What is necessary is just to integrally mold with the said case base using a metal material.

  Further, it is preferable that the inner wall surface of the concave portion is formed into a curved surface substantially parallel to the outer peripheral surface of the voice coil to be accommodated.

  Further, it is preferable that at least one long hole penetrating vertically is provided along the periphery of the magnet mounting position on the diaphragm.

  Furthermore, the magnet is a rectangular parallelepiped, and a metal cover that covers from the upper surface of the magnet to at least a part of the side surface is provided on the inner surface side of the lid. The metal cover is preferably made of a nonmagnetic material. And the recessed part which receives the magnet covered with the said metal cover is provided in the position corresponding to the said cover inner surface.

  Further, it is preferable that a pair of the fixing portions are provided at positions facing each other with the concave portion interposed therebetween, and both end portions of the diaphragm are fixed to the upper surface of each fixing portion.

  According to the bone conduction speaker of the present invention formed as described above, it is a structure in which a magnet is attached to a substantially central position on the upper surface of the diaphragm provided on the upper side of the voice coil, without requiring a complicated attachment structure, By reducing the weight and size of each component, the overall weight and size can be easily reduced, the manufacturing process can be simplified, and the manufacturing cost can be reduced. In particular, since the magnet is not located on the side of the voice coil, it can be made small enough to be easily connected to a small electronic device such as a mobile phone, PDA, or MP3 player. Become.

  In addition, a pole screw is formed on the case base, a voice coil is arranged here, and a diaphragm and a magnet are positioned on the upper part. Therefore, even if no magnet is arranged on the side of the voice coil, the bone The efficiency of conduction is not lowered, and sufficient efficiency can be maintained.

  In addition, a pole screw that protrudes above the approximate center of the bottom of the recess is integrated with the case base, and the voice coil is placed around the pole screw, maintaining excellent bone conduction efficiency while supporting downsizing. In particular, if the pole screw is integrally formed with the case base using a metal material, the manufacturing efficiency can be improved and the cost can be further reduced.

  In addition, since the inner wall surface of the concave portion is formed into a curved surface substantially parallel to the outer peripheral surface of the stored voice coil, excellent vibration efficiency can be maintained without impairing vibration of the voice coil.

  In addition, since at least one elongated hole penetrating vertically is provided along the periphery of the magnet mounting position on the diaphragm, the amplitude of the diaphragm can be increased to increase bone conduction efficiency.

  Further, the magnet is a rectangular parallelepiped, and a metal cover that covers at least a part of the side surface from the upper surface of the magnet to the inner surface side of the lid, particularly a metal cover made of a non-magnetic material, The magnet's magnetic lines can be concentrated on the voice coil side to increase the vibration efficiency and prevent the magnetic field lines from being exposed to the outside so that the magnetic force generated by the bone conduction speaker does not affect the human body. it can.

  Moreover, since the recessed part which receives the magnet covered with the said metal cover was provided in the position corresponding to the said cover body inner surface, bone conduction can be efficiently transmitted to a human body through the said cover body.

  In addition, a pair of the fixing portions are provided at positions facing each other across the recess, and both end portions of the diaphragm are fixed to the upper surface of each fixing portion, so that the vibration of the voice coil in the recess can be reliably ensured by a simple structure. A structure that can be transmitted to the diaphragm is realized.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  1 is a perspective view showing a bone conduction speaker according to a representative embodiment of the present invention, FIG. 2 is a longitudinal sectional view, FIG. 3 is an exploded sectional view, and FIG. 4 is an exploded perspective view. In the figure, reference numeral 1 is a bone conduction speaker, 2 is a case base, 3 is a voice coil, 4 is a diaphragm, 5 is a magnet, 6 is a metal cover, and 7 is a lid.

  2 to 4, the bone conduction speaker 1 includes a case base 2 in which a recess 25 having a substantially circular bottom surface 20 is formed, a voice coil 3 housed in the recess 25, and a case base 2. The diaphragm 4 is attached to the fixed portion 22 constituting the inner wall 23 of the concave portion 25 and is provided on the upper side of the voice coil 3 accommodated in the concave portion 25, and the substantially central position 40 on the upper surface side of the diaphragm 4. And a lid 7 attached to the upper part of the case base 2.

  A pole screw 21 that protrudes upward is disposed at a substantially central portion of the bottom surface 20 of the recess of the case base 2. The pole screw 21 is provided integrally with the case base 2, and the voice coil 3 is disposed around the pole screw 21. In addition, a pair of fixing portions 22 and 22 are provided at positions facing each other across the concave portion 25 of the case base 2, and the inner wall 23 of the concave portion 25 formed by the fixing portion 22 is formed by the voice coil 3. Is formed in a curved surface that is substantially parallel to the outer peripheral surface of the voice coil 3 and has a slightly larger radius than the voice coil 3.

  Both end portions 44, 44 of the diaphragm 4 are fixed to the upper surface of each fixing portion 22, so that the diaphragm 4 is installed above the concave portion 25 in which the pole screw 21 is accommodated. The height of the upper surface of the fixed portion 22 is formed to be slightly higher than the height of the upper surface of the pole screw 21. Therefore, a fixed gap is formed between the diaphragm 4 and the pole screw 21 in a state where the diaphragm 4 is installed between the fixed portions 22 and 22. Thus, the case base 2 has the effect of simplifying several components into one by acting as a yoke in addition to the role of fixing and supporting the voice coil 3 and the like.

  Thus, in order to make the pole screw 21 also serve as a yoke and to minimize the manufacturing process and the manufacturing cost, the pole screw 21 is desirably integrally formed with the case base 2 using a metal material. Specifically, the metal material can be formed by cutting or casting.

  The voice coil 3 is coupled to the pole screw 21 of the case base 2. Here, the thickness (height) of the voice coil 3 is set to be approximately the same as the height of the pole screw 21. Therefore, a certain gap is formed between the upper surfaces of the voice coil 3 and the pole screw 21 and the diaphragm 4.

  Further, both end portions of the coil wire of the voice coil 3 are extended from the bottom surface 20 to the lower surface of the case base 2 and electrically connected to a terminal 27 installed with an insulator 26 interposed as shown in FIG. It is connected. A sound signal is input to the voice coil 3 through the terminal 27.

  The vibration plate 4 is formed of a substantially flat plate-like member, and has a substantially circular vibration region 4 a similar to the shape of the bottom surface 20 of the recess and a fixed region 4 b having a shape similar to the upper surface shape of the fixing portion 22. These are passed over the voice coil 3 to vibrate at a predetermined frequency while preventing the voice coil 3 from being detached. In this example, the mounting screws 43, 43 penetrating through the through holes 42, 42 formed in the fixing region 4b of the diaphragm 4 are fixed to the screw holes 24, 24 formed on the upper surfaces of the fixing portions 22, 22, respectively. By doing so, it is constructed between the upper surfaces of the fixing portions 22 and 22.

  A plurality of elongated holes 41 penetrating vertically are formed along the circumferential direction around the periphery of the vibration region 4a of the diaphragm 4, that is, around the central position 40 where the magnet 5 is attached. Thus, by forming at least one long hole 41 in the vibration region 4a, the vibration efficiency or the bone conduction efficiency of the vibration plate 4 is improved. In this example, a total of four long holes 41 are formed at vertical and horizontal symmetrical positions. However, the number of the long holes 41 may be less than four or five or more. Various forms such as the position of each side of the pentagon, the position of each side of the hexagon, and the position along the circle are possible.

  The magnet 5 is a rectangular parallelepiped, is fixed at a substantially central position 40 of the vibration region 4 a on the upper surface of the diaphragm 4, and interacts with the voice coil 3 (attraction or repulsion). This magnet 5 is fixed to the inner vibration region 4a surrounded by the long holes 41,..., But this position is suitable in terms of vibration efficiency or bone conduction efficiency. The magnet 5 is preferably formed in a region corresponding to the center of the voice coil 3 or the center of the pole screw 21 in order to increase the vibration efficiency or the bone conduction efficiency. Therefore, conventionally, it has been necessary to provide a large number of magnets, but in the present invention, only one is sufficient. Of course, the number of magnets 5 is not limited at all, and two or more magnets can be used. In addition to the rectangular parallelepiped shape, a triangular prism, a cylinder, a pentagonal prism, and other various shapes can be employed.

  On the other hand, a metal cover 6 that covers from the upper surface of the magnet 5 to at least a part of the side surface thereof is provided so that the magnetic lines of force of the magnet 5 can go to the voice coil 3. The metal cover 6 is made of a metal material that cannot penetrate the magnetic force lines, for example, a non-magnetic material so that the magnetic force lines of the magnet 5 can be concentrated on the voice coil 3 side. The covering portion 62 is covered and fixed pieces 63 and 63 extending on both sides. A concave portion 70 for receiving the covering portion 62 of the metal cover 6 together with the magnet 5 is provided at a position corresponding to the magnet 5 on the inner surface of the lid body 7, and a through hole 60 drilled in the fixing piece 63 is provided. By attaching the penetrating mounting screw 61 to the screw hole 71 formed on the inner surface side of the lid body 7, the mounting screw 61 is fixed to the inner surface side.

  The bone conduction speaker 1 according to the present embodiment having the above structure operates as follows.

  First, when a current signal corresponding to a predetermined audio signal is transmitted to the voice coil 3, the voice coil 3 vibrates at a predetermined frequency by the magnetic force or attractive force of the magnet 5, the pole screw 21, and the inner wall 23 of the recess.

  The diaphragm 4 positioned on the upper part of the voice coil 3 is vibrated together by vibration transmitted from the voice coil 3 via the fixed portion 22. At this time, the diaphragm 4 is formed with a large number of elongated holes 41,..., And thus vibrates with a larger amplification than the voice coil 3.

  The vibration phenomenon of the diaphragm 4 is transmitted to the magnet 5 and the metal cover 6 mounted thereon, and is transmitted to the scalp of the human body through the lid body 7. Thereby, even a hearing-impaired person who has an abnormality in the eardrum or the ossicle in the skull of the human body can surely hear the sound if the cochlea and the auditory nerve are normal.

  Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can of course be implemented in various forms without departing from the gist of the present invention.

  Results of measuring the exposure of the magnetic force generated from the bone conduction speaker 1 of the embodiment of the present invention configured as described above and the exposure of the magnetic force from the bone conduction speakers of Comparative Examples 1 to 3 of other structures. Are shown in FIGS. 5 and 6, respectively.

  FIG. 5A is a result of the measurement of the magnetic force exposure of the bone conduction speaker of the embodiment shown in FIGS. 1 to 4, and FIG. The bone conduction speaker of Japanese Patent Application No. 2005-334524, that is, an extension part is formed on the yoke, a voice coil and a central magnetic pole are formed on the yoke, and a diaphragm with an iron piece attached to the upper part is fixed, and a magnet is attached to the upper part The result of the exposure measurement of the magnetic force of the made bone conduction speaker is shown.

  FIG. 6A shows, as Comparative Example 2, in addition to the structure of Comparative Example 1 above, as a result of measuring the magnetic force exposure of a bone conduction speaker having a structure in which an iron plate is further placed on the magnet. Is a bone conduction speaker described in JP-A-2006-33787 as Comparative Example 3, that is, a voice coil is attached to the central magnetic pole of the yoke, and the magnet is arranged on the short side end portions on both sides of the yoke, The result of the exposure measurement of the magnetic force of the bone conduction speaker which has arrange | positioned the diaphragm fixing | fixed part on the outer side of each said magnet on the said magnet arrangement | positioning axis | shaft is shown.

  The measurement results in FIGS. 5 and 6 indicate that the smaller the number of dots in the left semicircle, the smaller the amount of magnetic force exposed to the outside. In addition, the magnetic field lines are shown in the semicircle on the right side of the figure. As can be seen from FIGS. 5 and 6, in the embodiment, the magnetic force exposed to the outside is remarkably smaller than those in Comparative Examples 1 to 3, and the lines of magnetic force are almost converged. Therefore, it can be seen that the influence on the human body is also reduced. In Comparative Example 1, the magnetic force leaks upward in the upward direction of the magnet. Further, in Comparative Example 2, the amount of leakage is reduced by the amount of the iron plate placed, and the amount of leakage is supplemented so as to go to the lower yoke side. However, there is a leakage amount, which is not an ideal magnetic circuit. Even in Comparative Example 3, there was leakage to the outside.

1 is a perspective view showing a bone conduction speaker according to a representative embodiment of the present invention. Sectional drawing which similarly shows a bone conduction speaker. The disassembled sectional view which similarly shows a bone conduction speaker. The disassembled perspective view which similarly shows a bone conduction speaker. The figure which shows the result of having measured the exposure of the magnetic force of Example 1 and Comparative Example 1. The figure which shows the result of having measured the exposure of the magnetic force of the comparative examples 2 and 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bone conduction speaker 2 Case base 3 Voice coil 4 Diaphragm 4a Vibration area 4b Fixing area 5 Magnet 6 Metal cover 7 Lid 20 Bottom 21 Pole screw 22 Fixing part 23 Inner wall 24 Screw hole 25 Recess 26 Insulator 27 Terminal 40 Center Position 41 Long hole 42 Through hole 43 Mounting screw 44 End 60 Through hole 61 Mounting screw 62 Covering part 63 Fixed piece 70 Recessed part 71 Screw hole

Claims (9)

A case base in which a recess having a substantially circular bottom surface is formed;
A voice coil housed in the recess;
A diaphragm attached to a fixed portion constituting an inner wall of the recess in the case base, and passed over the voice coil housed in the recess;
A magnet attached to a substantially central position on the upper surface side of the diaphragm;
A lid attached to the upper part of the case base;
Bone conduction speaker characterized by comprising.   The bone conduction speaker according to claim 1, wherein a pole screw protruding upward from a substantially central portion of the bottom surface of the recess is provided integrally with the case base, and the voice coil is disposed around the pole screw.   The bone conduction speaker according to claim 2, wherein the pole screw is integrally formed with the case base using a metal material.   The bone conduction speaker according to any one of claims 1 to 3, wherein an inner wall surface of the recess is formed into a curved surface substantially parallel to an outer peripheral surface of a voice coil to be accommodated.   The bone conduction speaker according to any one of claims 1 to 4, wherein at least one elongated hole penetrating vertically is provided along a periphery of a magnet mounting position on the diaphragm.   The bone conduction speaker according to any one of claims 1 to 5, wherein the magnet is a rectangular parallelepiped, and a metal cover that covers at least a part of the side surface of the magnet is provided on the inner surface side of the lid. .   The bone conduction speaker according to claim 6, wherein the metal cover is made of a non-magnetic material.   The bone conduction speaker according to claim 6 or 7, wherein a concave portion for receiving the magnet covered by the metal cover is provided at a corresponding position on the inner surface of the lid.   The bone conduction according to any one of claims 1 to 8, wherein a pair of the fixing portions are provided at positions facing each other across the concave portion, and both end portions of the diaphragm are fixed to the upper surface of each fixing portion, respectively. speaker.