Patent Publication Number: US-9906866-B2

Title: Miniature speaker

Description:
FIELD OF THE INVENTION 
     The invention is related to electro-acoustic transducers, more particularly to a miniature speaker used in a portable consumer device. 
     DESCRIPTION OF RELATED ART 
     With the coming of mobile internet times, the quantity of intelligent mobile device is rising continuously. Among many mobile equipment, mobile phone is the most common and portable mobile terminal equipment. At present, the function of mobile phone is diversified. One of important functions is that of high quality music, and the miniature speaker in mobile phone is one of the essential conditions of realizing the function of high quality music. 
     The miniature speaker of relevant technology comprises a magnetic circuit system having a main magnet and a side magnet, wherein the main magnet and the side magnet are subjected to magnetization in vertical direction, and soft-magnetic material are applied to magnetism gathering. However, the efficiency of the magnetic circuit of such magnetic circuit system is not desirable and cannot satisfy users&#39; requirements for better sound performance. 
     Therefore, it is necessary to provide an improved miniature speaker to overcome above disadvantage. 
    
    
     
       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 isometric and exploded view of a miniature speaker in accordance with a first exemplary embodiment of the present disclosure. 
         FIG. 2  is an assembled view of the miniature speaker in  FIG. 1 . 
         FIG. 3  is a cross-sectional view of the miniature speaker in  FIG. 2 . 
         FIG. 4  is another cross-sectional view of the miniature speaker in  FIG. 2 . 
         FIG. 5  is an exploded view of a combination of a frame and a side magnet component of the miniature speaker in accordance with a second exemplary embodiment. 
         FIG. 6  is an exploded view of a combination of a frame and a side magnet component of the miniature speaker in accordance with a third exemplary embodiment. 
         FIG. 7  is an exploded view of a combination of a frame and a side magnet component of the miniature speaker in accordance with a fourth exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     The present invention will hereinafter be described in detail with reference to several exemplary embodiments. To make the technical problems to be solved, technical solutions and beneficial effects of the present disclosure more apparent, the present disclosure is described in further detail together with the figures and the embodiments. It should be understood the specific embodiments described hereby are only to explain this disclosure, not intended to limit this disclosure. 
     Embodiment 1 
     A miniature speaker  100  comprises a frame  10 , a cover plate  40  engaging with the frame  10  for forming an accommodating space, a magnetic circuit system  20  accommodated in the accommodating space, and a vibrating system  30  fixed on the frame  10  and accommodated in the accommodating space partially. The magnetic circuit system  20  is applied to generate magnetic field; while the vibrating system  30  produces sound when generating vibration in presence of drive force of the magnetic field generated by the magnetic circuit system  20 . 
     The frame  10  can be a plastic frame, or a yoke. As shown in  FIGS. 1-4 , the frame  10  specifically comprises a base plate  11  and multiple connecting pieces  12  which are arranged on the base plate  1 , wherein the base plate  11  is presented as a rectangle flat plate, and multiple connecting pieces  12  are arranged at each corner of the rectangle base plate  11  in order to fix multiple first side magnet components  23  in the magnetic circuit system  20 . In this embodiment, the base plate  11  is fabricated from the permeability magnetic material preferably, playing a role of magnetic conduction. Of course, the base plate  11  and the connecting piece  12  can also be fabricated from the plastics in other embodiments, and the base plate  11  and the connecting piece  12  are formed integrally. 
     Referring to  FIGS. 1, and 3-4 , the magnetic circuit system  20  comprises a main magnet  21  which is fixed on at the middle part of the base plate  11 , a first pole plate  22  which is adhered to the main magnet  21 &#39;s surface facing the cover plate  40  and multiple first side magnet components  23  which are fixed on the edge of the base plate  11  in the embodiment 1, wherein a magnetic gap  24  is formed between the main magnet  21  and multiple first side magnet components  23 ; and a voice coil  33  of the vibrating system  30  is inserted into the magnetic gap  24 . Each of the first side magnet components  23  comprises a first side magnet  231 , a second pole plate  232  and a second side magnet  233  which are stacked sequentially from the base plate  11  along the direction toward the cover plate  40 . In this embodiment, the main magnet  21  is magnetized along the vertical direction (the direction vertical to the base plate  11 , that is, the direction Z in  FIG. 1 ). The magnetizing direction of the first side magnet  231  is opposite to that of the main magnet  21 , and the magnetizing direction of the second side magnet  233  is opposite to that of the first side magnet  231 , that is, the magnetizing direction of the second side magnet  233  is the same as that of the main magnet  21 . 
     The magnetic circuit system of the miniature speaker as shown in  FIG. 1  is the system having five magnetic circuits, and four first side magnet components  23 , wherein two first side magnet components  23  are arranged on two opposite side surfaces of the main magnet  21  symmetrically, and another two first side magnet components  23  are arranged on another two opposite side surfaces of the main magnet  21  symmetrically. 
     As shown in  FIGS. 1-4 , two adjacent first side magnet components  23  are connected and fixed by means of one connecting piece  12  in this embodiment. The first side magnet components  23  are connected with corresponding connecting pieces  12  by means of gluing in this embodiment. However, the complementary matching structure can be formed between two ends of the first side magnet components  23  and the adjacent connecting pieces  12  in accordance with other embodiments of the present disclosure; therefore, the connecting strength between the first side magnet components  23  and the connecting pieces  12  can be strengthened. The complementary matching structure comprises but is not limited to an inserting part and a slot; for example, the inserting parts are arranged on two ends of the first side magnets  231 , the second pole plates  232  and the second side magnets  233  of the first side magnet components  23 , respectively; and the slots are arranged on the connecting pieces correspondingly. Preferably, the external surface of each first side magnet component  23  is aligned with the external surfaces of the connecting pieces  12  on two ends; thus, the acoustic performance of the miniature speaker can be improved. 
     Magnetic poles of the main magnet  21 , the first side magnets  231  and the second side magnets  233  in the embodiment 1 are shown in  FIG. 4 . The magnetic pole of the main magnet  21  which is positioned at the lower side (that is, one side close to the base plate  11 ) along the vertical direction is taken as the pole N, and the magnetic pole of the upper side (that is, one side far away from the base plate  11 ) is taken as the pole S; the magnetic pole of the first side magnet  231  which is positioned at the lower side (that is, one side close to the base plate  11 ) along the vertical direction is taken as the pole S, and the magnetic pole of the upper side (that is, one side far away from the base plate  11 ) is taken as the pole N; the magnetic pole of the second side magnet  233  which is positioned at the lower side (that is, one side close to the second pole plate  32 ) along the vertical direction is taken as the pole N, and the magnetic pole of the upper side is taken as the pole S. 
     The BL value can be increased greatly because the magnetic field intensity of the magnetic gap  24  where the voice coil  33  is positioned is improved greatly as a result of the first side magnet components  23  arranged in the embodiment and including the first side magnets  231  and the second side magnets  233  with magnetizing direction opposite to that of the first side magnets  231 . Thus, with same input voltage, the miniature speaker of the present disclosure can have better sensitivity for sound. 
     Further as shown in  FIGS. 1-4 , the vibrating system  30  comprises a diaphragm  31 , a dome  32  and a voice coil  33  which are overlapped from top to bottom and drive the diaphragm  31  to vibrate and sound in this embodiment, and the voice coil  33  is inserted into the magnetic gap  24  of the magnetic circuit system  20 . Therefore, the voice coil  33  of the vibrating system can give out sound by means of vibration in the way of driving the dome  32  to vibrate and driving the diaphragm  31  to vibrate. In this embodiment, the diaphragm  31  and the dome  32 , as well as the dome  32  and the voice coil  33  can be fixed with each other, for example, by means of gluing preferably. 
     Specifically as shown in  FIGS. 1-4 , the diaphragm  31  generally comprises a fixation part  311  which is positioned on an edge of the diaphragm, a vibrating main body part  312  which is positioned at the center of the diaphragm and presented as a flat plate in general and a suspension part  313  which extends from the periphery of the vibrating main body part  312  and positioned between the fixation part  311  and the vibrating main body part  312 , wherein the fixation part  311  is adhered to be place between the cover plate  40  and the connecting piece  12 . In the embodiment, the two ends of the dome  32  extend to the place under the suspension part  313 , that is, the project of the dome  32  on the base plate  11  is overlapped with the projection of the suspension  313  on the base plate  11  partially; therefore, the voice coil  33  which is fixed under the dome  32  can be closer to the first side magnet component  23  of the magnetic circuit system  20 , and more magnetic lines of force generated by the first side magnet component  23  can pass through the voice coil  33 . Of course, the dome  32  also can be arranged over the diaphragm  31 , and preferably positioned on the vibrating main body part  312  in other embodiments of the present disclosure. 
     Embodiment 2 
     Referring to  FIG. 5 , the difference from the first embodiment is that only two first side magnet components  23  are arranged, wherein the two first side magnet components  23  are arranged symmetrically on two opposite side surfaces of the main magnet  21  along the length direction of the base plate  11 . 
     Two second side magnet components  25  are arranged symmetrically on two opposite side surfaces of the main magnet  21  along the width direction of the base plate  11 . In this embodiment, each of the second side magnet components  25  comprises only the third side magnets  251  and the third pole plates  252  which are stacked from the base plate  11  along the direction pointing to the cover plate  40 , wherein the magnetizing direction of the third side magnet  251  is opposite to that of the main magnet  21 . 
     In this embodiment, each of the first side magnet components  23  and the adjacent second side magnet components  25  are connected and fixed together by means of the connecting pieces  12 . 
     Embodiment 3 
     Referring to  FIG. 6 , the difference is that the two first side magnet components  23  are arranged symmetrically on two opposite side surfaces of the main magnet  21  along the width direction of the base plate  11 , while two second side magnet components  25  are arranged symmetrically on two opposite side surfaces of main magnet  21  along the length direction of the base plate  11 . 
     Embodiment 4 
     Referring to  FIG. 7 , the difference is that the magnetic circuit system of the miniature speaker has three magnetic circuits, and two first side magnet components  23  are arranged only in this embodiment, wherein the two first side magnet components  23  are arranged symmetrically on two opposite side surfaces of the main magnet  21 . In this embodiment, the two first side magnet components  23  are arranged symmetrically on two opposite side surfaces of main magnet  21  along the length direction of the base plate  11 . At this time, the first connecting piece  12  extends along the width direction of the base plate  11  and connects with two first side magnet components  23 . 
     The BL value can be increased greatly because the magnetic field intensity of the magnetic gap  24  where the voice coil  33  is positioned is improved greatly as a result of the first side magnet component  23  arranged in the miniature speaker  100  of the present disclosure and the first side magnet component  23  includes the first side magnet  231  and the second side magnet  233  having magnetizing direction opposite to that of the first side magnet  231 . Thus, with same input voltage, the miniature speaker of the present disclosure can have better sensitivity for sound. 
     It is to be understood, however, that even though numerous characteristics and advantages of the present exemplary embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, 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 where the appended claims are expressed.