Patent Publication Number: US-9838795-B2

Title: Speaker

Description:
FIELD OF THE INVENTION 
     The present disclosure relates to electro-acoustic transducers, more particularly to a speaker having a diaphragm driven by a voice coil. 
     DESCRIPTION OF RELATED ART 
     With the rapid development of technology, audio devices are more and more popular. The people require not only the audio playing function of the audio devices, but also require higher reliability of audio devices. As more mobile multimedia technologies are developed particularly in 3G era, many audio devices are provided with many entertainment features, such as video playback, digital camera, games, GPS navigation and so on, more sophisticated and compact electronic components are required in audio devices. 
     The speaker is a common electronic component in audio devices and is used mainly for playback of audio signals. In the existing audio devices, the thickness of mobile phone, for example, is smaller, so that the speaker shall be thinner also. If the speaker is too thin, the vibration amplitude of the vibrating diaphragm is reduced, that will affect seriously the low frequency performance of the speaker. Therefore, the existing long stroke speaker with better low frequency performance is developed and the thickness is small enough, so that such a speaker can solve well the problems of traditional speaker. The magnetic circuit system of the long stroke speaker includes usually two pairs of magnets separated each other as drive magnets. The voice coil of the vibration system moves in reciprocating mode in the magnet gap between the magnets. However, the magnetic flux leakage in the magnetic circuit system of the long stroke speaker is serious. The vibration amplitude of the voice coil is difficult to be controlled. The voice coil is easier to tear the vibrating diaphragm in larger vibration amplitude; and the sound quality is affected. 
     Therefore, it is necessary to provide a new speaker to overcome the problems mentioned above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the embodiment can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
         FIG. 1  is an isometric exploded view of a speaker in accordance with an exemplary embodiment of the present disclosure. 
         FIG. 2  is a cross-sectional view of the speaker in  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT 
     The present invention will hereinafter be described in detail with reference to an exemplary embodiment. To make the technical problems to be solved, technical solutions and beneficial effects of present disclosure more apparent, the present disclosure is described in further detail together with the figures and the embodiment. It should be understood the specific embodiment described hereby is only to explain this disclosure, not intended to limit this disclosure. 
     As shown in  FIGS. 1 and 2 , a speaker  1  in accordance with an exemplary embodiment of the present disclosure, includes a vibration system  10 , a magnetic circuit system  11 , a housing  12  for assembling the vibration system  10  and the magnetic circuit system  11 , a front cover  13  and a rear cover  14  assembled on the housing  12  to create a space to accommodate the vibration system  10  and the magnetic circuit system  11 . 
     The magnetic circuit system  11  includes a first magnet group  15 , a second magnet group  16  and a third magnet group  17 , which are lined up in turn along a vibration direction X-X of the vibration system  10 . The first magnet group  15  and the third magnet group  17  may be attached with the second magnet group  16 , or may be separated each other. In an optional embodiment, the first magnet group  15 , the second magnet group  16 , and the third magnet group  17  are fixed respectively on an inner surface of the housing  12 . The second magnet group  16  is magnetized along the vibration direction X-X of the vibration system  10 . The first magnet group  15  and the third magnet group  17  are magnetized along a direction vertical to the vibration direction X-X of the vibration system  10 . 
     The first magnet group  15  includes a first magnet  150  and a second magnet  151 , which are separated with their opposite magnetic poles faced each other. The second magnet group  16  includes a third magnet  160  and a fourth magnet  161 , which are separated with their opposite magnetic poles faced each other. Two magnetic poles of the third magnet  160  and two magnetic poles of the fourth magnet  161  are close to each other respectively. N-pole of the third magnet  160  and S-pole of the fourth magnet  161  are separated and faced each other. S-pole of the third magnet  160  and N-pole of the fourth magnet  161  are separated and adjacent to each other. The third magnet group  17  includes a fifth magnet  170  and a sixth magnet  171 , which are separated with their opposite magnetic poles faced each other. The gap between the first magnet  150  and the second magnet  151 , the gap between the third magnet  160  and the fourth magnet  161 , and the gap between the fifth magnet  170  and the sixth magnet  171  create cooperatively a magnetic gap  18 . 
     The vibration system  10  includes a vibrating diaphragm  100  with its circumferential edge fixed on the housing  12  and a flat voice coil  101  which drives the vibrating diaphragm  100  to vibrate. One end of the voice coil is suspended in the magnetic gap  18 . The flat voice coil  101  vibrates along its vibration direction X-X. 
     The third magnet  160  is located between the first magnet  150  and the fifth magnet  170 . The fourth magnet  161  is located between the second magnet  151  and the sixth magnet  171 . The magnetic pole of the first magnet  150  close to the second magnet  151  and the magnetic pole of the fifth magnet  170  close to the sixth magnet  171  are opposite to each other. As shown in  FIG. 2 , optionally, N-pole of the third magnet  160  is close to the first magnet  150 . Accordingly, S-pole of the third magnet  160  is close to the fifth magnet  170 . By virtue of the configuration, the flat voice coil  101  vibrates in reciprocating mode under force in the magnetic gap  18  between the first magnet  150  and the second magnet  151 , as well as in the magnetic gap  18  between the fifth magnet  170  and the sixth magnet  171 . When the voice coil  101  moves to the magnetic gap  18  between the third magnet  160  and the fourth magnet  161 , because the magnetic field in opposite direction exerts an opposite force on the voice coil  101 , the vibration amplitude of the voice coil  101  is limited. Not only that, the second magnet group  16  can play a role also to separate the first magnet group  15  and the third magnet group  17 , so as to increase the magnetic flux density within the magnetic gap  18 , and reduce the magnetic flux leakage of the third magnet group  15  and the third magnet group  17 . 
     In an optional embodiment, the first magnet  150  and the second magnet  151  are in parallel. The third magnet  160  and the fourth magnet  161  are in parallel. The fifth magnet  170  and the sixth magnet  171  are in parallel. 
     The cross section of the housing  12  is in a runway tubular shape. The housing  12  includes a front opening  120  for assembling the vibrating diaphragm  100  and a rear opening  120  relative to the front opening  121 . The front opening  120  and the rear opening  121  are connected. The front cover  13  is installed on the front opening  120 . The circumferential edge of the vibrating diaphragm  100  is fixed between the front cover  13  and the housing  12 . The rear cover  14  is installed on the rear opening  121 . The front cover  13  is provided also a sound outlet  130 . The sound from the vibrating diaphragm  100  is emitted from this sound outlet  130 . 
     The vibrating diaphragm  100  includes a suspension  1000  with its circumferential edge fixed on the housing  12 , and a center dome top  1001  connected to the suspension  1000 . The flat voice coil  101  includes a voice coil wire  1010  in flat and annular shape and a coil bracket  1011  with one end fixed on the center dome top  1001 . The voice coil wire  1010  is fixed on the voice coil bracket  1011 . 
     In the speaker  1  disclosed above, the vibrating diaphragm  100  can have bigger vibration amplitude, so that the speaker  1  has a better low-frequency sound effect, in addition, the vibration amplitude of the voice coil  101  can be controlled effectively. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present embodiment have been set forth in the foregoing description, together with details of the structures and functions of the embodiment, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.