Patent Publication Number: US-2007104346-A1

Title: Speaker

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a structure of a speaker.  
      The present application claims priority from Japanese Patent Application No. 2005-313133, the disclosure of which is incorporated herein by reference.  
      2. Description of the Related Art  
      Typically, various network elements such as choke coils, capacitors, or resistances are connected to a speaker in order to control acoustic signals or electric signals inputted to the speaker. Conventionally, the network elements are housed in a control box which is separately formed from a speaker frame. The network elements are connected via an extension cord to a relay terminal mounted on the speaker frame. For example, for a vehicle-mounted speaker, however, the wiring must be carried out after securing a space of control box to be mounted in a door or a console of the vehicle, that is, the conventional speaker has a disadvantage that a complicated mounting operation of the network elements is requested. Then, in Japanese Patent Application Laid-Open No. 2005-236424, a speaker P 1  having a network element N 1  directly mounted on a speaker frame F 2  is disclosed as shown in  FIG. 1 .  
      In the speaker P 1  as mentioned above, the network element N 1  is fixed on a rear surface of the speaker frame F 2 , protruding rearward. In other words, it is necessary to separately provide a fixing structure for fixing the network elements at a rear portion of the speaker frame. In the speaker as mentioned above, there may be a danger that the network element is damaged when or after mounting the speaker since it is protruded rearwards. In addition, the speaker as mentioned above has a disadvantage in which an extra space for mounting the network element is needed separately because of protruding rearwards.  
     SUMMARY OF THE INVENTION  
      The present invention is made for solving the above-mentioned problems. Specifically, an object of the present invention is to provide a speaker with a network element, a simple structure of which can prevent the network element from being damaged by an outer force, and another object is to provide a speaker with a network element which requires no extra mounting space and also no special fixing structure for the network element.  
      According to the present invention, there is provided a speaker having a diaphragm, an outer frame for supporting an outer end of the diaphragm, a voice coil bobbin provided with a voice coil on an outer surface thereof, and a damper for supporting an inner end of the diaphragm and the voice coil bobbin as described in the preamble of claim  1 . The speaker comprises a magnetic circuit, which is disposed at a sound emission side of the diaphragm, for driving the diaphragm, a magnetic circuit supporting member for supporting the magnetic circuit at a tip portion thereof protruding in a sound emission direction, the magnetic circuit supporting member being formed at a central portion inside the outer frame supporting the diaphragm, and a network element provided within the magnetic circuit supporting member in order to control acoustic signals inputted to the speaker. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      These and other objects and advantages of the present invention will become clearly understood from the following description with reference to the accompanying drawings, wherein:  
       FIG. 1  is a diagram showing a schematic construction of a conventional speaker;  
       FIG. 2  is a sectional view for explaining a speaker  1  according to a first embodiment of the present invention;  
       FIG. 3  is a sectional view for explaining a speaker  1   b  according to a second embodiment of the present invention;  
       FIG. 4  is a sectional view for explaining a speaker  1   c  according to a third embodiment of the present invention; and  
       FIG. 5  is a sectional view for explaining a speaker  1   d  according to a fourth embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      A speaker according to one embodiment of the present invention comprises a diaphragm, a magnetic circuit disposed at the sound emission side of the diaphragm for driving the diaphragm, a magnetic circuit supporting member located below the magnetic circuit within a speaker frame, and a network element provided inside the magnetic circuit supporting member to control acoustic signals inputted to the speaker. The magnetic circuit supporting member is disposed at an inside central portion of a frame member which supports the diaphragm and forms an entire or a part of the speaker outer frame. Further, the magnetic circuit supporting member penetrates a central portion of the diaphragm from a rear portion of the speaker, and supports the magnetic circuit at a tip thereof protruding into the sound emission side.  
      In the speaker as mentioned above, it is possible to prevent the network element such as choke coil, capacitor or resistance from breaking with the simple construction of speaker according to the present invention since the network element is provided within the magnetic circuit supporting member. The network element controls acoustic signals (electric signals) inputted, for example, to the voice coil or the like. Further, since there is provided the network element within the magnetic circuit supporting member, there is no need to provide an extra mounting space for mounting the network element. Additionally, there is no need also to separately provide a fixing structure for the network element.  
      Some embodiments of the speaker of the present invention will be explained hereinafter with reference to the attached drawings.  
     First Embodiment  
       FIG. 2  is a sectional view for explaining a speaker  1  concerned with a first embodiment of the present invention  
      As shown in  FIG. 2 , the speaker  1  of the present embodiment includes a frame body  10 A, a magnetic circuit supporting member  10 B, a first plate  11 , a magnet  12 , a second plate  13 , a supporting frame  14 , a yoke  15 , a voice coil bobbin  16 , a first voice coil  16 A, a second voice coil  16 B, a diaphragm  17 , an edge  18 , a damper  19 , and a network element  20 . The magnetic circuit supporting member  10 B corresponds to one embodiment of the magnetic circuit supporting member concerned with the present invention. The network element  20  corresponds to one embodiment of the network element concerned with the present invention. Also, a magnetic circuit  100  comprising, for example, the first plate  11 , the magnet  12 , the second plate  13 , the supporting frame  14 , and the yoke  15 , corresponds to one embodiment of the magnetic circuit concerned with the present invention. The respective sections will be explained hereinafter in detail.  
      As shown in  FIG. 2 , for example, the speaker  1  concerned with the present embodiment schematically comprises the substantially cup-shaped frame body  10 A which forms an outer wall portion of the speaker  1  and the substantially cylinder-shaped magnetic circuit supporting member  10 B which is integrally formed with the frame body  10 A to concentrically extend toward an opening side from a central depth portion thereof. The frame body  10 A and the magnetic circuit supporting member  10 B corresponds to a frame member  10  which forms an entire of or a part of speaker outer wall and supports a diaphragm  17 . In the present embodiment, a side surface  101  of the speaker frame provided with vent holes is formed adjacently to the frame body  10 A.  
      The magnetic circuit supporting member  10 B includes a recessed portion  110  therein which has an opening in an opposite direction of the sound emission side, and also the recessed portion  110  extends until around central portion of the magnetic circuit supporting member  10 B. Inside the recessed portion  110 , there is provided the network element  20 .  
      As shown in  FIG. 2 , the ring-shaped first plate  11  having a larger outer diameter than that of the magnetic circuit supporting member  10 B is concentrically fixed at a tip surface of the magnetic circuit supporting member  10 B. Also, the cylindrical magnet  12  having a smaller outer diameter than that of the first plate  11  is concentrically fixed at the sound emission side of the first plate  11 . Further, at the sound emission side of the magnet  12  is concentrically fixed the second plate  13  having the same outer diameter as one of the first plate  11 . In addition, the cylindrical supporting frame  14  having a larger outer diameter than the respective ones of the first plate  11 , the magnet  12  and the second plate  13  is concentrically fixed at the sound emission side of the second plate  13 .  
      The supporting frame  14  is provided with a circular-annular groove  14 A to have an opening formed concentrically with the body of supporting frame  14  and extended in the opposite direction of sound emission. The circular-annular groove  14 A has an inner diameter smaller and an outer diameter larger than the respective outer diameters of the first and second plates  11 ,  13 . The depth of the groove  14 A, i.e., the width of the supporting frame  14  toward a central axis (o) thereof, is set larger than amplitude of the diaphragm  17 . In the present embodiment, as shown in  FIG. 2 , the supporting frame  14  is fixed with a screw-shaped fixing member  120  located along the common central axis (o) of the first plate  11 , the magnet  12  and the second plate  13 .  
      The ring-shaped yoke  15  is concentrically fixed on a back surface of the supporting frame  14  as shown in  FIG. 2 . The yoke  15  has the same inner diameter as the outer diameter of the groove  14 A. Magnetic gaps  51  are formed between the inner peripheral surface of yoke  15  and the respective outer peripheral surfaces of the first and second plates  11 ,  13 , respectively. In such a way, the magnetic circuit  100  is formed by the first plate  11 , the magnet  12 , the second plate  13 , the supporting frame  14  and the yoke  15 .  
      The voice coil bobbin  16  is concentrically set in the direction of the central axis (o) between the frame body  10 A and the magnetic circuit  100  comprising the first plate  11 , the magnet  12  and the second plate  13  so that the voice coil bobbin  16  can be vibrated freely along the direction of the central axis (o). A front end portion of the voice coil bobbin  16  is inserted into the magnetic gap  51  which is formed between the first plate  11 , the second plate  13  and the yoke  15 .  
      In the magnetic gap  51 , the first voice coil  16 A and the second voice coil  16 B are wound around the outer peripheral surface of first plate  11  and the outer peripheral surface of second plate  13 , respectively. The inner peripheral portion of diaphragm  17  with a cone shape is fixed on an outer peripheral surface of the voice coil bobbin  16  at a rear end thereof, whilst the outer peripheral portion of diaphragm  17  is supported by the outer peripheral portion of front edge of the frame body  10 A through the edge  18 . The damper  19  is provided between the rear end of the voice coil bobbin  16  to which one end of the diaphragm  17  is attached and the frame body  10 A. The voice coil bobbin  16  and the diaphragm  17  are supported by the damper  19  so as to be vibrated freely along the direction of the central axis (o).  
      As already mentioned above, the network element  20  is fixed within the recessed portion  110  of the magnetic circuit supporting member  10 B at the back surface side of the frame  10 . The network element  20  is an electronic element for controlling the acoustic signal or electric signal inputted into the speaker, and comprises, for example, a choke coil, a capacitor or a resistance. In the embodiment of  FIG. 2 , the choke coil  21  is used as the network element  20 , a central axis of which is disposed substantially along the central axis (o) of the frame  10  or the magnetic circuit supporting member  10 B. In other words, the choke coil  21  as the network element  20  is wound around the central axis substantially parallel to the central axis (o) of the frame  10  or the magnetic circuit supporting member  10 B.  
      In the speaker  1  having the configuration as mentioned above, the acoustic signal (electric signal) is inputted from a terminal portion  130  provided on a side surface of the frame body  10 A through the network element  20 , so that electric current flows from the network element  20  to the first voice coil  16 A and the second voice coil  16 B. As a result, the voice coil bobbin  16  vibrates along the direction of the central axis (o) through an operation of a magnetic field formed by the magnet  12 , and thus the diaphragm  17  is vibrated to output sound wave (compression wave).  
      In such a way, according to the speaker of the present invention, the network element  20  is stored within the recessed portion surrounded by the magnetic circuit supporting member  10 B which supports the magnetic circuit  100  at a tip portion thereof. The magnetic circuit  100  for driving the diaphragm  17  is located at the sound emission side of the diaphragm  17 . The magnetic circuit supporting member  10 B forms an entire of or a part of the speaker&#39;s outer frame, and is disposed at a central portion of and an inside of the frame  10 , the tip portion of which protrudes in the direction of sound emission. As an effect thereof, any damage of the network element  20  can be prevented with s simple construction as mentioned above. Further, since the network element is disposed within the magnetic circuit supporting member  10 B, there is no need of providing an extra space for mounting the network element  20 . Additionally, any special construction for fixing the network element  20  is not necessary.  
      More specifically, the magnetic circuit supporting member  10 B includes the above-mentioned recessed portion  110  which has an opening in the direction opposite to the sound emission side. Through disposing the network element  20  within the recessed portion  110 , the speaker  1  of the present invention can be obtained.  
      Since the network element  20  can be integrally attached with the main body of speaker in such a way, the efficiency of attaching operation can be remarkably improved when adopting the speaker  1  as a vehicle-mounted speaker.  
      In addition, since the network element  20  is provided within the magnetic circuit supporting member  10 B, the influence of the network element  20  to the magnetic circuit  100  is decreased, thereby preventing any deterioration in performance of the speaker.  
      Further, according to the speaker  1  as mentioned above, the magnetic circuit  100  is disposed at the sound emission side of the diaphragm  17  with the cone shape, that is, inside a cone thereof, so that the speaker  1  can be formed thinner, which is advantageous when mounting it on the vehicle.  
     Second Embodiment  
       FIG. 3  is a sectional view for explaining a speaker  1   b  concerned with the second embodiment of the present invention. Whilst the choke coil  21  as the network element  20  of the speaker  1  concerned with the first embodiment is wound around the concentric central axis (o) with a magnetic circuit supporting member  10 B and the frame  10  within the magnetic circuit supporting member  10 B, the network element  20  of the speaker  1   b  concerned with the second embodiment are wound around another central axis  20 P which is located in the recessed portion  110  formed by the magnetic circuit supporting member  10 B. The central axis  20 P is substantially orthogonal to the central axis (o) of the frame  10  or the magnetic circuit supporting member  10 B. Specifically, the speaker  1   b  of the present embodiment adopts the choke coil  21  as the network element, which is wound around the central axis  20 P orthogonal to the central axis (o). As shown in  FIG. 3 , the other parts of the speaker  1   b  are substantially the same as those of the speaker  1 , and thus the same reference numerals as those in  FIG. 2  are assigned to the same parts.  
      Since the network element  20  is disposed in the direction orthogonal to the direction of thickness of speaker  1   b,  the height of magnetic circuit supporting member  10 B along the central axis (o) can be reduced more than that of the speaker  1  concerned with the first embodiment. Thereby, the thickness of the speaker  1   b  can be decreased.  
     Third Embodiment  
       FIG. 4  is a sectional view for explaining a speaker  1   c  concerned with the third embodiment of the present invention. As shown in  FIG. 4 , the speaker  1   c  has a plurality of network elements, i.e., the choke coil  21  and a capacitor  22 , within the magnetic circuit supporting member  10 B. The choke coil  21  is mounted along the central axis  21 P which is substantially parallel to the central axis (o) of the frame  10  or the magnetic circuit supporting member  10 B. Further, the capacitor  22  is located adjacently to the choke coil  21 , the central axis  22 P of which is also substantially parallel to the central axis (o) of the frame  10  or the magnetic circuit supporting member  10 B. Here, a longer axis of the capacitor  22  is set to become the central axis  22 P. The other parts of the speaker  1   c  are substantially the same as those of the speaker  1 ,  1   b,  then any explanation with regard to the same parts are omitted.  
      According to the speaker  1   c  of the third embodiment, a plurality of network elements can be provided therein, which is different from the speaker  1 ,  1   b  of the first and second embodiment.  
      In addition, since the choke coil  21  and the capacitor  22  are separately fixed within the magnetic circuit supporting member  10 B, in which the respective central axes of the choke coil  21  and the capacitor  22  are disposed substantially parallel to the central axis (o) of the frame  10  or the magnetic circuit supporting member  10 B. As a result, even if an inner diameter of the recessed portion  110  within the magnetic circuit supporting member  10 B in the central axis direction is small, a plurality of network elements can be located within the magnetic circuit supporting member  10 B.  
     Fourth Embodiment  
       FIG. 5  is a sectional view for explaining a speaker  1   d  concerned with the fourth embodiment of the present invention. As shown in  FIG. 5 , the speaker  1   d  has a plurality of network elements, i.e., the choke coil  21  and the capacitor  22 , within the magnetic circuit supporting member  10 B. The choke coil  21  is mounted along the central axis  21 P which is substantially orthogonal to the central axis (o) of the frame  10  or the magnetic circuit supporting member  10 B. Further, the capacitor  22  is located adjacently to the choke coil  21 , the central axis  22 P of which is also substantially orthogonal to the central axis (o) of the frame  10  or the magnetic circuit supporting member  10 B. Additionally, the capacitor  22  is disposed at an inner side of the choke coil  21 , i.e., at the side of sound emission. The other parts of the speaker  1   d  are substantially the same as those of the speaker  1 ,  1   b,    1   c,  then the explanation with regard to the same parts are omitted.  
      As mentioned above, the speaker  1   d  concerned with the present embodiment has the plurality of network elements  20 , i.e., the choke coil  21  and the capacitor  22  within the magnet circuit supporting member  10 B, in which the choke coil  21  and the capacitor  22  are separately attached adjacently to each other, each central axis of which is substantially orthogonal to the central axis (o) of the frame  10  or the magnetic circuit supporting member  10 B. As a result thereof, compared with the third embodiment, the length of the magnetic circuit supporting member  10 B along the central axis (o) is further reduced, so that the thickness of the speaker  1   d  can be decreased.  
      Moreover, the present invention is not limited to the above mentioned embodiments.  
      That is, although the choke coil  21  and the capacitor  22  were explained as the network element  20  in above description, the present invention is not limited to such a configuration. For example, the network elements  20  may include a various kind of electronic elements such as resistance, amplifier element, switching element, or transistor, other than the choke coil  21  and the capacitor  22 . Through these network elements  20 , the acoustic signal (electric signal) inputted into the voice coil can be controlled more accurately.  
      Further, although the speaker with the cone-shaped diaphragm was explained in the above mentioned embodiments, the present invention is not limited to this configuration. That is, the diaphragm may have a various kind of shapes, such as cone, dome, plane, circle, or ellipse.  
      Moreover, although the speaker with an electrically conductive type driving system was used for explanation in the above mentioned embodiments, the present invention is not limited to this configuration. A various kind of driving systems, for example, such as electromagnetic type, electrostatic type or piezoelectric type may be adopted. Further, the magnetic circuit may be either one of an inner magnet type or an outer magnet type. In a word, the most important matter for the present invention is that the network element/elements  20  is/are provided within the magnetic circuit supporting member  10 B.  
      In such a way, according to the speaker of the present invention, the network element  20  is provided within the magnetic circuit supporting member  10 B which supports the magnetic circuit  100  at a tip portion thereof. The magnetic circuit  100  for driving the diaphragm  17  is located at the sound emission side of the diaphragm  17 . The magnetic circuit supporting member  10 B forms an entire of or a part of the speaker&#39;s outer frame, and is disposed at a central portion of and an inside of the frame  10 , the tip portion of which protrudes in the direction of sound emission. As an effect thereof, any damage of the network element  20  can be prevented with a simple construction as mentioned above. Further, since the network element is provided within the magnetic circuit supporting member  10 B, there is no need of providing an extra space for attaching the network element  20 . Additionally, any special construction for fixing the network element  20  is not necessary in the present invention.  
      While the present invention has been described in connection with the preferred specific embodiments thereof, it will be understood that the description is intended to illustrate and does not limit the scope of the present invention, which is defined just by the following claims.