Patent Publication Number: US-8995704-B2

Title: Micro-speaker

Description:
FIELD OF THE INVENTION 
     The present disclosure relates to the art of speakers and, particularly to a micro-speaker having a suspension attached on a coil. 
     DESCRIPTION OF RELATED ART 
     With the continuing development of audio and sound technology, micro-speakers have been widely used in electronic devices, such as cellular phones, PDAs (personal digital assistants), and so on. 
     A micro-speaker related to the present invention includes a case having a sound hole, a frame attached to the case for forming a chamber together with the case, a magnetic circuit system received in the chamber and having a magnetic gap, a diaphragm mounted on the frame, and a voice coil attached to a lower surface of the diaphragm and suspended in the magnetic gap. The voice coil has a body attached to the lower surface of the diaphragm and a pair of leading wires drawn out from the body and suspended in the chamber. While electrified, the voice coil will be activated to vibrate by the electromagnetic Ampere Force and further drives the diaphragm to vibrate, which converts the electrical signals to sound waves. 
     However, the leading wires of the voice coil are suspended in the chamber. When the vibrating amplitude of the voice coil is enhanced, the leading wires will meet the frame. As the result, the leading wires will be broken. In another hands, only one end of the voice coil is fixed by the diaphragm, so that the vibration of the diaphragm introduces unbalanced when the vibrating amplitude the voice coil is enhanced. 
     Therefore, it is desirable to provide a micro-speaker which can overcome the above-mentioned problems. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the embodiments 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 illustrative assembly view of a micro-speaker according to a first exemplary embodiment of the present invention; 
         FIG. 2  is a cross-sectional view of the micro-speaker taken along line II-II of  FIG. 1 . 
         FIG. 3  is an illustrative exploded view of the micro-speaker of  FIG. 1 . 
         FIG. 4  is an illustrative top view of the micro-speaker of the  FIG. 1 , a diaphragm, a magnetic system and a cover thereof being removed away. 
         FIG. 5  is an illustrative top view of a suspension of a micro-speaker according to a second exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     Referring to  FIGS. 1-3 , a micro-speaker  100 , according to a first exemplary embodiment, includes a frame  11 , a diaphragm  12  mounted on the frame  11 , a magnetic system received in the frame  11  and defining a magnetic gap  101 , a voice coil  13  attached to the diaphragm  12  for driving the diaphragm  12  and suspended in the magnetic gap  101 , a suspension  14  mounted on the frame  11  and assembled on the voice coil  13 , a pair of contacts  17  coupled with the suspension  14  for providing electrical signals to the voice coil  13 , and a case  18  covering a periphery of the diaphragm  12 . The micro-speaker  100  has a longitudinal direction L 1  and a lateral direction L 2  perpendicular to the longitudinal direction L 1 . 
     Referring to  FIGS. 2 and 3 , the frame  11  includes a base portion  110  and a receiving room  111  surrounded by the base portion  110 . The base portion  110  has a pair of longitudinal sidewalls  112 , a pair of lateral sidewalls  113  connected with the adjacent longitudinal sidewalls  112 , a pair of longitudinal engaging portions  114  extending from the longitudinal sidewalls  112  towards the receiving room  111 , a pair of lateral engaging portions  115  extending from the lateral sidewalls  113  towards the receiving room  111  for engaging with the magnetic system together with the longitudinal engaging portions  114 , and at least a pair of slots  116  extending from an upper surface of the lateral engaging portions  115  towards a lower surface of the lateral engaging portions  115  for fixing the suspension  14 , respectively. Each longitudinal engaging portion  114  is unconnected with the adjacent lateral engaging portions  115  for forming a plurality of leakage channels  117 . Each longitudinal engaging portion  114  has a pair of engaging bars  118  extending from two ends thereof for fixing the magnetic system on the frame  11  firmly. The frame  11  further has four semi-columned protrusions  119  extending upwardly and perpendicularly from an upper surface of the base portion  110  for engaging with the case  18 . 
     Referring to  FIGS. 2 and 3 , the voice coil  13  has a first end  131  connected with the diaphragm  12 , a second end  132  opposite to the first end  131  and suspended in the magnetic gaps  101 , a connecting sidewall  133  connecting the first and second ends  131 ,  132 , and a pair of leading wires  134  drawn out from the first end  131 . In fact, the voice coil can be directly connected to the diaphragm, and can also be connected to the diaphragm via a medium. 
     Referring to  FIGS. 1-3 , the magnetic system is received in the receiving room  111  and engaged with the longitudinal and lateral engaging portions  114 ,  115 . The magnetic system has a yoke  10 , a magnet  15  received in the yoke  10  and a pole plate  16  attached to an upper surface of the magnet  15 . The yoke  10  has a bottom  102 , a pair of longitudinal side portions  103  extending upwardly and perpendicularly from the bottom  102  in the longitudinal direction L 1 , and a pair of lateral side portions  104  extending upwardly and perpendicularly from the bottom  102  in the lateral direction L 2 . The longitudinal side portions  102  are unconnected with the lateral side portions  104 , thereby forming four corners  105  for communicating with the leakage channels  117  to adjust the interior sound pressure of the micro-speaker  100 . Each longitudinal side portion  103  has a pair of fixing holes  106  for cooperatively engaging with the fixing bars  118  of the frame  11 , thereby fixing the yoke  10  on the frame  11  firmly. 
     Referring to  FIGS. 2-4 , the suspension  14  comprises a circle body portion  141  connected with the second end  132  of the voice coil  13  and at least a pair of connecting portions  142  protruded outwardly from the circumference of two ends of the body portion  141 . Each connecting portion  142  has a pair of protruding arms  1421  protruded outwardly from the circumference of one end of the body portion  141  and separated from each other, a pair of bending arms  1422  extending from each protruding arm  1421  and towards each other, and a pair of fixing arms  1423  connected with the corresponding bending arms  1422  and separated from each other. The body portion  141  is coplanar with respect to the connecting portions  142  for ensuring the vibrating of the diaphragm  12  is stable and balanced. 
     Referring to  FIGS. 2-4 , the pair of contacts  17  is received in the frame  11 . Each contact  17  has a contacting portion  171  coupled with the corresponding fixing arm  1423  of the connecting portion  142  of the suspension  14 , a holding portion  172  extending downwardly from the contacting portion  171  and received in the frame  11 , and a soldering portion  173  extending from the holding portion  172  and exposed from the frame  11  for coupled with exterior electrical signals. The contacting portions  17  are parallel to the soldering portions  173 . 
     Referring to  FIGS. 2-4 , when assembled, the fixing arms  1423  are fixed and inserted in the slots  116  and the protruding arms  1421  and the bending arms  1422  are suspended in the receiving room  111  of the frame  11  for ensuring the vibration of the voice coil  13 . The leading wires  134  are fixed and coupled with the suspension  14  and the pair of contacts  17  are received in the frame  11  and connected the exterior electrical signals to the suspension  14 , thereby providing electrical signals to the voice coil  13 . 
     Referring to  FIG. 3 , the diaphragm  12  includes a central area  121  in the center thereof, a jointing area  122  at an outer periphery thereof, and a connecting area  123  between the central area  121  and the jointing area  122 . The central area  121 , the jointing area  122  and the connecting area  123  are coaxial with the suspension  14  and the magnetic system  12 . The connecting area  113  is curved upwardly or downwardly to form an annular bugle or concave. In fact, the jointing area  122  is the periphery covered by the case  18 , as mentioned above. 
     Referring to  FIG. 3 , the case  18  attaches onto the frame  10  to cover the jointing area  122  of the diaphragm  11 . The case  18  includes a base  180 , and a sound outlet  181  formed in the center of the base  180 . The base  180  has four semi-columned recesses  182  at the four corners thereof to engage with the corresponding semi-columned protrusions  119  of the frame  11 , thereby the mechanical connection between the frame  11  and the case  18  is obtained and secured. Sound generated by the micro-speaker  100  is transmitted to the outside of the micro-speaker  100  through the sound outlet  191 . 
     Referring to  FIG. 5 , the second embodiment of the present invention is similar to the first embodiment of the present invention except that the structure of a suspension of a micro-speaker. The suspension has a circle body portion  141 ′ and at least a pair of connecting portions  142 ′ protruded outwardly from the circumference of two ends of the body portion  141 ′. Each connecting portion  142 ′ has a pair of protruding arms  1421 ′ protruded outwardly from the circumference of one end of the body portion  141 ′ and separated from each other, a pair of bending arms  1422 ′ extending from each protruding arm  1421 ′ and towards each other, and a fixing arm  1423  connecting the pair of bending arms  1422 ′. The body portion  141 ′ is coplanar with respect to the connecting portions  142 ′. In this embodiment, each connecting portion cooperates with the corresponding outer periphery of the body portion for forming a closed curve for improving the manufacturing efficiency of the suspension. 
     According to the micro-speaker, the suspension connects with the second end of the coil for limiting the vibrating of the voice coil and preventing the excessive amplitude of the voice coil. The leading wires are fixed on the suspension for preventing the broken of the leading wires when the vibrating amplitude of the voice coil is enhanced. The diaphragm cooperates with the suspension for fixing the coil firmly, thereby ensuring the vibrating of the diaphragm is stable and balanced. 
     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.