Abstract:
The present invention is to provide a speaker having a long voice coil bobbin and a plurality of dampers, wherein each of the dampers is formed with a central hole for connecting to the long voice coil bobbin at a position adjacent to a lower or upper end of a cone frame of the speaker for enabling the long voice coil bobbin to stably vibrate due to the balance effect of the dampers. In addition, since a ratio of 3˜6 is defined between the length of the long voice coil bobbin and winding length of a voice coil unit of the speaker, the long voice coil bobbin is able to perform the true frequency and amplitude of mega bass more precisely and transmit the vibration to a diaphragm of the speaker for enhancing the vibration strength of the diaphragm and improving the sound quality and volume of the speaker effectively.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a speaker, more particularly to a speaker having a long voice coil bobbin and a plurality of dampers, wherein a first damper and a second damper made of corrugated damping membranes are formed with a central hole respectively for connecting to the long voice coil bobbin at a position adjacent to a lower or upper surface of a cone frame of the speaker, so as to enable the long voice coil bobbin to stably and reciprocally vibrate in the speaker due to the balance effect of the first and second dampers. In addition, since a better ratio is defined between the length of the long voice coil bobbin and winding length of a voice coil unit of the speaker, the weight of the long voice coil bobbin is greater than that of the voice coil bobbin of a traditional speaker having the same power, so as to enable the long voice coil bobbin to perform the true frequency and amplitude of mega bass more precisely and to transmit the vibration to a diaphragm of the speaker for enhancing the vibration strength of the diaphragm and the sound quality and volume of the speaker. 
       BACKGROUND OF THE INVENTION 
       [0002]    Generally, a consumer electronic product (such as a mobile phone, a navigation device, a speaker, an audio device, a walkman, a handheld game console or the like) is provided with at least one speaker for playing sounds including music or voices. Recently, with the development of electronic technologies, various consumer electronic products are rapidly developed and improved to meet the trend of compactness and miniaturization. Therefore, each of the consumer electronic products only can be provided with a speaker with smaller size, such that the sound volume played by the speaker is apparently lower. Especially, the speaker can not provide outstanding performance in the portion of low frequencies. As a result, when a user uses such a consumer electronic products to play sounds, the user can not hear clear and resonant sounds, and can not fully enjoy the powerful bass efficiency of the speaker. 
         [0003]    Referring now to  FIG. 1 , a traditional speaker structure  10  is illustrated. As shown, the traditional speaker structure  10  comprises a frame body  11 , a metal gasket  16 , an annular magnet  12 , a voice coil bobbin  13 , a damper  14 , a diaphragm  15  and a T-shape yoke  17 , wherein the frame body  11  is formed with a receiving space  111  therein. A central position of a lower surface of the frame body  11  is formed with a first through hole  112 , while a central position of an upper surface of the metal gasket  16  is formed with a second through hole  161 . The upper surface of the metal gasket  16  is attached to the lower surface of the frame body  11 , so that the second through hole  161  can be communicated with the first through hole  112 . A central position of an upper surface of the annular magnet  12  is formed with a third through hole  121 , and the upper surface of the annular magnet  12  is attached to a lower surface of the metal gasket  16 , so that the third through hole  121  can be communicated with the second through hole  161 . A first end of the voice coil bobbin  13  is wound with a voice coil unit  131 , and the length of the voice coil bobbin  13  is twice (generally, 2 to 2.5 times) as long as the winding length of the voice coil unit  131 . The first end of the voice coil bobbin  13  and the voice coil unit  131  thereon pass through the first through hole  112  and the second through hole  161 , and received in the third through hole  121  of the annular magnet  12 . Thus, the annular magnet  12  surrounds the first end of the voice coil bobbin  13  and the voice coil unit  131  thereon, while a second end of the voice coil bobbin  13  is received in the receiving space  111  of the frame body  11 . The damper  14  is a concentric corrugated membrane sleeved on the second end of the voice coil bobbin  13 . An outer edge of the damper  14  is horizontally connected to an inner periphery of the frame body  11 . The diaphragm  15  is attached to an inner periphery of one side end of the frame body  11 , and extended toward the receiving space  111 , wherein a central position of the diaphragm  15  is connected to the second end of the voice coil bobbin  13 . The T-shape yoke  17  is made of metal material, and a central position of an upper surface of the T-shape yoke  17  is extended upward to form a pole  171 , wherein the upper surface of the T-shape yoke  17  is attached to a lower surface of the annular magnet  12 , so that the pole  171  can insert into an inner space of one end of the voice coil bobbin  13 . Therefore, when an electric current passes through the voice coil unit  131 , the voice coil unit  131  will be energized to generate an electromagnetic effect, wherein magnetic lines of forces generated by the voice coil unit  131  as well as the annular magnet  12 , the metal gasket  16  and the T-shape yoke  17  surrounding the voice coil unit  131  can commonly generate attractive and repulsive forces. Therefore, according to variation of the strength and direction of the electric current of sound signals inputted into the voice coil unit  131 , the voice coil bobbin  13  wound with the voice coil unit  131  will reciprocally vibrate. As a result, the diaphragm  15  will simultaneously vibrate corresponding to the vibration of the voice coil bobbin  13 , so that the traditional speaker structure  10  can generate sounds. 
         [0004]    However, in the traditional speaker structure  10 , because the length of the voice coil bobbin  13  is only 2 to 2.5 times of the winding length of the voice coil unit  131  wound on the voice coil bobbin  13 , the length of the voice coil bobbin  13  is too short and the weight thereof is too light. Thus, when the voice coil unit  131  is energized to generate the attractive and repulsive forces between the voice coil unit  131  and the annular magnet  12 , the voice coil bobbin  13  wound with the voice coil unit  131  reacts against the attractive and repulsive forces too sensitively and rapidly due to insufficient length and weight of the voice coil bobbin  13 . As a result, the voice coil bobbin  13  can not fully transmit vibrations to the diaphragm  15 , so that the vibration strength of the diaphragm  15  is insufficient. It may cause that the bass strength generated by the traditional speaker structure  10  is relatively low, resulting in losing the sound quality. Thus, the traditional speaker structure  10  can not perform true bass effect. 
         [0005]    Furthermore, since the cross-sectional angle between the reciprocal vibration pathway of the voice coil bobbin  13  of the traditional speaker structure  10  and the frame body  11  (i.e. an inclination angle of an outer periphery of the frame body  11 ) is too large, the impact force generated due to the reciprocal vibration of the voice coil bobbin  13  can not be efficiently buffered. Meanwhile, the counterforce generated due to the impact force causes the annular magnet  12 , the metal gasket  16  and the T-shape yoke  17  mounted below the frame body  11  to transiently move toward a reverse direction, so that the partial vibration strength of the diaphragm  15  will be neutralized. In addition, the annular magnet  12 , the metal gasket  16  and the T-shape yoke  17  of the traditional speaker structure  10  are used to provide the kinetic energy for the reciprocal vibration of the voice coil bobbin  13 . Thus, when the voice coil bobbin  13  wound with the voice coil unit  131  generates the reciprocal vibration according to the variation of the electric current inputted into the voice coil unit  131  to cause the simultaneous vibration of the diaphragm  15  with the voice coil bobbin  13 , the voice coil bobbin  13  and the diaphragm  15  will generate the impact force to the frame body  11  due to the reciprocal vibration, and the frame body  11  can not fully buffer the impact force generated by the reciprocal vibration of the voice coil bobbin  13  and the diaphragm  15  due to the cross-sectional angle of the frame body  11  and the included angle of the reciprocally linear vibration pathway of the voice coil bobbin  13  are too large angles. As a result, the frame body  11  is easily affected by the impact force to generate a resonance effect, so as to neutralize the partial vibration strength of the diaphragm  15 , resulting in the distortion of the sound quality generated by the traditional speaker structure  10 . 
         [0006]    As a result, it is important for the inventor to think how to develop an innovative speaker to solve the foregoing problems existing in the traditional speaker structure by increasing the length of a long voice coil bobbin in the speaker to provide a better ratio between the length of the long voice coil bobbin and the winding length of a voice coil unit thereon and to extend the frequency range and amplitude of the long voice coil bobbin, so as to increase the vibration strength of a diaphragm of the speaker and carry out the extension effect of the frequency range of the speaker, for the purpose of enhancing the sound quality of the speaker. 
         [0007]    It is therefore tried by the inventor to develop a speaker having a long voice coil bobbin and a plurality of dampers, so that a user can enjoy clearer sounds and best bass effect when the user listens to sounds played by the speaker. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    An object of the present invention is to provide a speaker having a long voice coil bobbin and a plurality of dampers, wherein the speaker comprises a cone frame, a magnetic element (such as an assembly of a magnet and a yoke), a long voice coil bobbin, a first damper, a second damper and a diaphragm. The cone frame is made of a one-piece metal plate formed by punching or casting, and an upper surface of the cone frame is formed with an opening. A receiving space is defined in the cone frame, and a central position of a lower surface of the cone frame is formed with a through hole. A central position of an upper surface of the magnetic element is provided with a receiving recess, and the upper surface of the magnetic element is attached to the lower surface of the cone frame, so that the receiving recess is communicated with the through hole. The long voice coil bobbin is a hollow tube, wherein a first end thereof is wound with a voice coil unit which is at least one metal wire wound on the first end of the long voice coil bobbin by a predetermined manner. The length of the long voice coil bobbin is at least 3 to 6 times of the winding length of the voice coil unit, while the outer diameter of the long voice coil bobbin and the voice coil unit is slightly smaller than the inner diameter of the through hole and the receiving recess. Thus, the first end of the long voice coil bobbin and the voice coil unit wound thereon can pass through the through hole and extend downward out of the cone frame for inserting into the receiving recess of the magnetic element, while a second end of the long voice coil bobbin is received in the receiving space of the cone frame. The first damper and the second damper are concentric corrugated damping membranes, each of which is formed with a central hole. An inner edge of the central hole of the first damper is sleeved and mounted on a position of the long voice coil bobbin adjacent to the lower surface of the cone frame, while an inner edge of the central hole of the second damper is sleeved and mounted on a position of the long voice coil bobbin adjacent to the upper surface of the cone frame. Outer edges of the first and second dampers are horizontally connected to an inner periphery of the cone frame. The diaphragm is attached to an inner edge of the opening of the cone frame, and extended toward the receiving space, wherein a central portion of the diaphragm is connected to the second end of the long voice coil bobbin. Therefore, when an electric current passes through the voice coil unit on the first end of the long voice coil bobbin to energize the voice coil unit, the voice coil unit will generate magnetic lines of force, wherein the magnetic lines of force generated by the voice coil unit and magnetic lines of force generated by the magnetic element can commonly generate attractive and repulsive forces, so as to actuate the long voice coil bobbin to reciprocally vibrate and to cause the diaphragm to simultaneously vibrate corresponding to the vibration of the long voice coil bobbin for oscillating the ambient air in front of the speaker to generate sounds. Meanwhile, the long voice coil bobbin will stably and reciprocally vibrate in the through hole on the lower surface of the cone frame based on the balance effect of the first and second dampers. Because the maximum length of the voice coil bobbin of the traditional speaker is only 2.5 times of the winding length of the voice coil unit wound thereon, the weight of the voice coil bobbin is insufficient. Therefore, when the voice coil unit of the traditional speaker is energized to generate the attractive and repulsive forces between the voice coil unit and the magnetic element, the voice coil bobbin reacts against the attractive and repulsive forces too sensitively and rapidly due to the insufficient weight of the voice coil bobbin. As a result, it may cause that the bass strength generated by the traditional speaker structure is relatively low to cause the loss of the sound quality, so that the traditional speaker structure can not perform true bass effect. Because the speaker of the present invention has the long voice coil bobbin and a better ratio is defined between the length of the long voice coil bobbin and the winding length of the voice coil unit, the weight of the long voice coil bobbin in the speaker of the present invention is greater than that of the voice coil bobbin of the traditional speaker having the same power. Therefore, when the long voice coil bobbin in the speaker of the present invention is actuated to reciprocally vibrate by the attractive and repulsive forces generated between the voice coil unit and the magnetic element, the reaction time of the long voice coil bobbin reacting against the attractive and repulsive forces is several milliseconds slower than that of the voice coil bobbin of the traditional speaker. As a result, the long voice coil bobbin can perform the true frequency and amplitude of mega bass more precisely, and the vibration can be transmitted to the diaphragm, so that the vibration strength of the diaphragm is sufficient to oscillate the ambient air to perform the true mega bass effect, for the purpose of substantially enhancing the sound quality and volume of the speaker of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0009]    The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein 
           [0010]      FIG. 1  is a cross-sectional view of a traditional speaker structure; 
           [0011]      FIG. 2  is an exploded perspective view of a speaker having a long voice coil bobbin and a plurality of dampers according to a preferred embodiment of the present invention; and 
           [0012]      FIG. 3  is an assembled cross-sectional view of the speaker having a long voice coil bobbin and a plurality of dampers according to the preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    The present invention is a speaker having a long voice coil bobbin and a plurality of dampers. Referring now to  FIG. 2 , in a preferred embodiment of the present invention, a speaker  20  comprises a cone frame  21 , a magnetic element  22 , a long voice coil bobbin  23 , a first damper  24 , a second damper  25  and a diaphragm  26 , wherein the cone frame  21  is made of a one-piece metal plate formed by punching or casting. An upper surface of the cone frame  21  is formed with an opening  211 , and a receiving space  212  is defined in the cone frame  21 , while a central position of a lower surface of the cone frame  21  is formed with a through hole  213 . 
         [0014]    As describe above, the magnetic element  22  comprises a first yoke  221 , an annular magnet  222  and a second yoke  226 , wherein the first yoke  221  is made of metal material, such as iron, and a central position of an upper surface of the first yoke  221  is formed with a first receiving hole  223 . The upper surface of the first yoke  221  is attached to the lower surface of the cone frame  21 , so that the first receiving hole  223  of the first yoke  221  is communicated with the through hole  213  of the cone frame  21 . A central position of an upper surface of the annular magnet  222  is formed with a second receiving hole  224 , and the upper surface of the annular magnet  222  is attached to a lower surface of the first yoke  221 , so that the second receiving hole  224  of the annular magnet  222  is communicated with the first receiving hole  223  of the first yoke  221 . Thus, a receiving recess  225  is defined between the second receiving hole  224  and the first receiving hole  223 , while the receiving recess  225  is communicated with the through hole  213 . The second yoke  226  is made of metal material, such as iron, and a central position of an upper surface of the second yoke  226  is formed with a central pole  227  (i.e. central post) made of metal material, so that the cross section of the second yoke  226  is T-shape. The outer diameter of the central pole  227  is slightly smaller than the inner diameter of the long voice coil bobbin  23  and the inner diameter of the receiving recess  225 . The upper surface of the second yoke  226  is attached to a lower surface of the annular magnet  222 , while the central pole  227  can pass through the receiving recess  225  and insert into the one end of the long voice coil bobbin  23 . 
         [0015]    Referring now to  FIGS. 2 and 3 , the long voice coil bobbin  23  is a hollow tube, wherein the aforesaid end of the long voice coil bobbin  23 , also referred to as the first end, is peripherally wound with a voice coil unit  231  which is at least one metal wire wound on the first end of the long voice coil bobbin  23  by a predetermined manner. The length of the long voice coil bobbin  23  is at least 3 to 6 times of the winding length of the voice coil unit  231 , while the outer diameter of the long voice coil bobbin  23  and the outer diameter of the voice coil unit  231  are slightly smaller than the inner diameter of the through hole  213  and the inner diameter of the receiving recess  225  (i.e. the first receiving hole  223  and the second receiving hole  224 ). Thus, the first end of the long voice coil bobbin  23  and the voice coil unit  231  wound thereon can pass through the through hole  213  and extend downward out of the cone frame  21  for inserting into a peripheral space around the central pole  227  of the second yoke  226  and being received in the receiving recess  225  of the magnetic element  22 , while a second end of the long voice coil bobbin  23  opposite to the first end is received in the receiving space  212  of the cone frame  21 . 
         [0016]    As described above, the first damper  24  and the second damper  25  are concentric corrugated damping membranes, wherein the first damper  24  is formed with a first central hole  241 , and the second damper  25  is formed with a second central hole  251 . An inner edge of the first central hole  241  of the first damper  24  is sleeved and mounted on a position of the long voice coil bobbin  23  adjacent to the lower surface of the cone frame  21 , while an inner edge of the second central hole  251  of the second damper  25  is sleeved and mounted on a position of the long voice coil bobbin  23  adjacent to the upper surface of the cone frame  21 . Outer edges of the first damper  24  and second damper  25  are horizontally connected to an inner periphery of the cone frame  21 . Furthermore, the diaphragm  26  is attached to an inner edge of the opening  211  of the cone frame  21 , and extended toward the receiving space  212 , wherein a central portion of the diaphragm  26  is connected to the second end of the long voice coil bobbin  23 . 
         [0017]    Therefore, when an electric current passes through the voice coil unit  231  on the first end of the long voice coil bobbin  23  to energize the voice coil unit  231 , the voice coil unit  231  will generate magnetic lines of force, wherein the magnetic lines of force generated by the voice coil unit  231  and magnetic lines of force generated by the magnetic element  22  can commonly generate attractive and repulsive forces, so as to actuate the long voice coil bobbin  23  to reciprocally vibrate and to cause the diaphragm  26  to simultaneously vibrate corresponding to the vibration of the long voice coil bobbin  23  for oscillating the ambient air in front of the speaker  20  to generate sounds. Meanwhile, the long voice coil bobbin  23  will stably and reciprocally vibrate in the through hole  213  on the lower surface of the cone frame  21  based on the balance effect of the first and second dampers  24 ,  25 . Because the speaker  20  of the present invention has the long voice coil bobbin  23  and a better ratio is defined between the length of the long voice coil bobbin  23  and the winding length of the voice coil unit  231  (the length of the long voice coil bobbin  23  is at least 3 to 6 times of the winding length of the voice coil unit  231 ), the weight of the long voice coil bobbin  23  in the speaker  20  of the present invention is greater than that of the voice coil bobbin of the traditional speaker having the same power. Therefore, when the long voice coil bobbin  23  in the speaker  20  of the present invention is actuated to reciprocally vibrate by the attractive and repulsive forces generated between the voice coil unit  231  and the magnetic element  22 , the reaction time of the long voice coil bobbin  23  reacting against the attractive and repulsive forces is several milliseconds slower than that of the voice coil bobbin of the traditional speaker. As a result, the long voice coil bobbin  23  can extend the ranges of frequency and amplitude, and transmit vibrations to the diaphragm  26 , so that the vibration strength of the diaphragm  26  is sufficient to oscillate the ambient air to increase the extension effect of frequency and amplitude. As a result, the sound quality of the speaker  20  of the present invention can be substantially enhanced, wherein the transmission speed and effect are based on the length, the weight, the material of the long voice coil bobbin  23  and the material, the weight and the winding length of the voice coil unit  231 . 
         [0018]    Referring to  FIG. 2  again, in the preferred embodiment, the long voice coil bobbin  23  is further formed with a plurality of heat dissipating holes  232  thereon. In operation, the voice coil unit  231  on the long voice coil bobbin  23  will generate heat during the electric power passes through the resistance of the voice coil unit  231 , and the heat will be transmitted to the speaker  20  via the long voice coil bobbin  23 , resulting in raising the temperature of the speaker  20 . Thus, the heat dissipating holes  232  can be used to increase the air circulation in the long voice coil bobbin  23  and the contact area between the long voice coil bobbin  23  and the ambient air. Meanwhile, the heat dissipation efficiency of the long voice coil bobbin  23  can be increased, so as to prevent the long voice coil bobbin  23  from be over-heated, aged or burned. The amount and the diameter of the heat dissipating holes  232  can be increased or reduced according to actual desire, wherein the heat dissipating holes  232  may be completely removed in some special cases. 
         [0019]    Referring to  FIG. 2  again, in the preferred embodiment, the lower surface of the cone frame  21  is radially and equidistantly formed with a plurality of first screw holes  214  close to an edge of the through hole  213 , while the upper surface of the magnetic element  22  is formed with a plurality of second screw holes  228  corresponding to the first screw holes  214 . Furthermore, the speaker  20  further comprises a plurality of fastening screws  215 , each of which passes through the corresponding first and second screw holes  214 ,  228  in turn, so as to fasten the lower surface of the cone frame  21  to the upper surface of the magnetic element  22 . 
         [0020]    In addition, in the preferred embodiment, a central position of an upper surface of the diaphragm  26  is formed with a tweeter cap (i.e. a dust cap)  261  corresponding the second end of the long voice coil bobbin  23 . The long voice coil bobbin  23  comprises an inner layer  233  and an outer layer  234 . The inner layer  233  and the outer layer  234  are made of different material. For example, the material of the inner layer  233  of the long voice coil bobbin  23  can be ASV aluminum, metal material or composite material, wrapped material, etc., and the material of the outer layer  234  can be rubber, resin, etc. The friction coefficient of the surface of the inner layer  233  of the long voice coil bobbin  23  is smaller than that of the surface of the outer layer  234  of the long voice coil bobbin  23 . Therefore, when the long voice coil bobbin  23  in the speaker  20  is actuated to reciprocally vibrate due to the attractive and repulsive forces generated between the voice coil unit  231  and the magnetic element  22 , the flow speed of the air inside the long voice coil bobbin  23  is greater than that of the air outside the long voice coil bobbin  23  because the friction coefficient of the surface of the inner layer  233  of the long voice coil bobbin  23  is smaller than that of the surface of the outer layer  234  of the long voice coil bobbin  23 . After this, the long voice coil bobbin  23  causes the air to impact the diaphragm  26  and the tweeter cap  261 . Because the speed of the air of the surface of the inner layer  233  of the long voice coil bobbin  23  for impacting the tweeter cap  261  is several milliseconds faster than that of the air of the surface of the outer layer  234  of the long voice coil bobbin  23  for impacting the tweeter cap  261 , the true frequency and amplitude of the midrange and tweeter can be precisely performed. As a result, not only the outer layer  234  of the long voice coil bobbin  23  of the speaker  20  can generate a bass effect more real than the traditional speaker structure, but also the inner layer  233  of the long voice coil bobbin  23  performs the true frequency and amplitude of the midrange and tweeter. Thus, various ranges of sounds generated by the speaker  20  can be more perfect than that of the traditional speaker structure. 
         [0021]    Moreover, in other embodiments of the present invention, it should be noted that the first yoke  221 , the annular magnet  222  and the second yoke  226  can be further received in the receiving space  212  of the cone frame  21 , if necessary. 
         [0022]    The present invention has been described with the preferred embodiments thereof and it is understood that many changes and modifications to the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.