Patent Publication Number: US-2006008108-A1

Title: Loudspeaker structure

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      This invention relates to a loudspeaker structure, and more particularly to a loudspeaker capable of improving acoustic effect and reducing thickness without changing the output power and the anti-magnet effect.  
      2. Description of the Prior Arts  
      As shown in  FIG. 1 , a conventional inner-magnet loudspeaker structure includes a frame  11  that is interiorly provided from inside outward with a voice coil  12 , an elastic wave  13 , a nylon thread  14  and a cone paper  15 . A dust-proof cover  16  is provided at the center inside of the cone paper  15 , and a terminal  17  is arranged on the outer periphery of the frame  11  for exterior electrical connection. On an outer end of the frame  11  is sequentially provided a front piece  18 , a magnet  19  and a yoke iron  21 . And a conventional outer-magnet loudspeaker structure is shown in  FIG. 2  and the difference is that on an outer end of the frame  11  is sequentially provided a front piece  22 , a first magnet  23 , a rear piece  24 , a second magnet  25  and an anti-magnet cover  26 . However, both the inner-magnet and the outer-magnet loudspeaker still have some defects that are to be explained as follows:  
      First, the inner-magnet and the outer-magnet loudspeaker use the cone paper  15  as vibration device, and the front pieces  18 ,  22 , the magnets  19 ,  23 ,  25  and the other components are assembled on and protrude out of the outer end of the frame  11 . In this case, the thickness of the loudspeaker is increased, so that the loudspeaker is inapplicable to products of small size, such as TFT (thin film transistor) type flat LCD (liquid crystal display), LCD flat type TV and Plasma Display Panel Television (PDPT), or the auto or household acoustics. These TV products are light and thin. If the conventional inner-magnet or the outer-magnet loudspeaker are assembled inside or outside these light and thin TV products by force, it will occupy a lot of space, so that there is no surplus space structure can be spared to resonate with the speaker, which will lead to decrease in output power and acoustic quality of the TV products.  
      Second, the frame  11  is normally made of iron material, and at the bottom center of the frame is formed a through hole  111  for reception of the front piece  18 ,  22 , the voice coil  12  and others components. The through hole  111  will be diverged from the bottom center of the frame  11  in case that a mistake is caused when assembling the frame  11 . Thus, the acoustic effect will not be good.  
      Third, the voice of the loudspeaker is produced by vibration of the cone paper  15 , and the cone paper  15  is cone-shaped and which is not interiorly provided with spacer structure. Thus, sound waves produced by the cone paper  15  will interfere with one another during transmission, so that acoustic effect of the loudspeaker will not be good.  
      Fourth, with reference to  FIG. 3 , a sound box  27  is equipped with two inner-magnet loudspeakers, and there is no spacer between the cone papers  15 , so that sound source point of the high-pitched wave and that of the base-tone wave are not clear. Furthermore, since the loudspeaker occupies a lot of space, the corresponding sound box  27  used to cooperate with the loudspeaker should be large enough in order to provide optimum acoustic quality.  
      The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional loudspeaker structure.  
     SUMMARY OF THE INVENTION  
      The primary object of the present invention is to provide a loudspeaker structure capable of reducing the thickness without changing the output power and the anti-magnet effect.  
      The second object of the present invention is to provide a loudspeaker structure capable of decreasing the defective ratio during the assembly process of the loudspeaker.  
      Another object of the present invention is to provide a loudspeaker structure having better acoustic quality.  
      Yet another object of the present invention is to provide a loudspeaker structure wherein the sound source point of the loudspeaker is quite clear.  
      A loudspeaker structure in accordance with one aspect of the present invention comprises a bowl-shaped frame, a central column is integrally formed in the frame and faces an opening end of the frame, the central column axially formed with a through hole, and a fixing element passing through the through hole for fixing a front piece, a magnet and a yoke iron on top surface of the central column.  
      The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment in accordance with the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an assembly cross sectional view of a conventional inner-magnet loudspeaker;  
       FIG. 2  is an assembly cross sectional view of a conventional outer-magnet loudspeaker;  
       FIG. 3  shows a conventional inner-magnet loudspeaker is assembled in a sound box;  
       FIG. 4  is an assembly cross sectional view of a loudspeaker in accordance with the present invention;  
       FIG. 5  shows the loudspeaker in accordance with the present invention is emitting sound waves;  
       FIG. 6  shows the loudspeaker assembled in a sound box in accordance with the present invention is emitting sound waves;  
       FIG. 7  is a cross sectional view of showing a loudspeaker in accordance with the present invention wherein the central column is provided with ventilation holes;  
       FIG. 8  is an assembly cross sectional view of a loudspeaker in accordance with another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Referring to  FIG. 4 , a loudspeaker structure in accordance with an embodiment of the present invention is shown and generally includes a bowl-shaped frame  30 . A central column  40  is integrally formed at the center of a bottom surface  31  inside the frame  30  and faces opening end of the frame  30 . The central column  40  is axially formed with a through hole  41 , in which, is screwed with a screw nut  42 . A voice coil  51  is provided on the outer periphery of the central column  40 . On the inner periphery  32  of the frame  30  are provided from inside outward with an elastic wave  52 , a nickel fiber  53  and a cone paper  54 , respectively. The cone paper  54  is adhered to the periphery of the voice coil  51 , and a fixing element  60  is screwed with the screw nut  42  after passing through the through hole  41 . A front piece  55 , a magnet  56  and a yoke iron  57  are sequentially arranged on the top end of the central column  40 . On the outer periphery of the frame  30  is further provided with terminals  58  for exterior electrical connection.  
      Since the central column  40  is formed in the opening end of the frame  30 , and the front piece  55 , the magnet  56  and the yoke iron  57  are arranged on the top end of the central column  40 , the thickness of the loudspeaker can be substantially reduced. Thus, the loudspeaker, under the condition that the output power is not reduced, is applicable to products having small structural space, such as TFT type flat LCD, LCD flat type TV, PDPT, or the auto or household acoustics.  
      Besides, the loudspeaker in accordance with the present invention further has the advantages as follows:  
      First, the frame  30  replaces the conventional frame, and the central column  40  is integrally formed in the opening end of the frame  30 . Such structural design allows the central column  40  to be accurately formed on the center of the bottom surface of the frame  30 , and to further allow the rest components of the loudspeaker to be arranged accurately on the top surface of the central column  40  without any alignment operation. Thereby, the defective fraction caused in assembly of the loudspeaker is reduced, and the cost is accordingly decreased.  
      Second, as shown in  FIG. 5 , the central column  40  is formed at the bottom center of the frame  30 , and on the outer periphery of the central column  40  are provided with the elastic wave  52  and the voice coil  51 . The cone paper  54  is located between the voice coil  51  and the frame  30 . In this case, the central column  40  is located in the center of the cone paper  54  and acts as a spacer, such that, when the loudspeaker is in use, the central column  40  will reflect the sound wave (indicated by the dotted line) produced by the cone paper  54  (including the yoke iron  57 ). Thus the reflection effect of the sound wave is clear, and accordingly the acoustic effect is improved.  
      Third, as shown in  FIG. 6 , the loudspeaker in accordance with the present invention can be set in the sound box  70  of the acoustic equipments. Furthermore, the central column  40  is formed in the opening end of the frame  30  and located in the cone paper  54  in a protruding manner. In this case, the trace of the sound wave produced by the cone paper  54  and reflected by the central column  40  is quite regular, such that the direction of the sound wave between the loudspeakers is clear, and sound source points A are also clear. Thereby, the acoustic effect will be improved. Furthermore, the thickness of the loudspeaker is reduced without influencing the output power, and the corresponding sound box can be accordingly smaller as compared to the conventional one.  
      It will noted that, as shown in  FIG. 7 , plural ventilation holes  43  are coaxially and symmetrically formed around the through hole  41  of the central column  40 , and the quantity of the ventilation holes  43  can be 2, 4 or 6. Besides the above-mentioned advantages, when the loudspeaker is in use after being assembled in the sound box of acoustic equipments, since the central column  40  is axially formed with plural ventilation holes  43  allowing flow of air, the ventilation holes  43  can balance the air pressure caused by vibration of the loudspeaker, so that the acoustic effect can be improved.  
      Referring to  FIG. 8 , a frame of loudspeaker in accordance with another embodiment of the present invention is shown. In which, the central column  40  of the frame  30  is hollow and interiorly provided with a chock  80  which is interiorly received with a screw nut  81  for screwing with the fixing element  60 . And thus the front piece  55 , the magnet  56  and the yoke iron  57  are allowed to be assembled on the top surface of the central column  40 . The loudspeaker in this embodiment has the same functions as the loudspeaker of the first embodiment does, so further explanations will be omitted.  
      While we have shown and described various embodiments in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.