Abstract:
A voice coil motor (VCM) includes a moving unit, a fixing unit, an elastic plate, and a conducting pole. The moving unit includes a moving barrel and a coil assembly around the moving barrel. The coil assembly includes a connecting portion. The moving barrel defines a blind hole on an upper surface thereof, one end of a conducting pole being received in the blind hole. The fixing unit defines a through hole receiving the moving unit. The elastic plate is connected between the moving barrel and the fixing unit. The conducting pole provides a stable electrical connection between the elastic plate and the connecting portion notwithstanding movements of the moving barrel.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure relates to voice coil motors (VCMs) and, particularly, to a VCM with connective stability. 
         [0003]    2. Description of Related Art 
         [0004]    VCMs may include a moving unit, a fixing unit, and an elastic plate connected between the moving unit and the fixing unit. The moving unit includes a coil assembly, and the fixing unit includes a magnet assembly. The moving unit is received in the fixing unit and is driven to move relative to the fixing unit by a magnetic force generated by the coil assembly in the magnet assembly, causing the elastic plate to deform. The elastic plate restores the moving unit when the magnetic force vanishes. The coil assembly is also electrically connected to the elastic plate by soldering and functions as electrodes of the coil assembly. However, a solder joint between the coil assembly and the elastic plate may easily deteriorate or break during the deformation of the elastic plate. 
         [0005]    Therefore, it is desirable to provide a VCM, which can overcome the limitations described. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is an assembled view of a VCM in accordance with an exemplary embodiment. 
           [0007]      FIG. 2  is an isometric, exploded view of the VCM of  FIG. 1 . 
           [0008]      FIG. 3  is similar to  FIG. 2 , but viewed from another angle. 
           [0009]      FIG. 4  is an assembled view of an upper spring and a moving unit of the VCM of  FIG. 1 . 
           [0010]      FIG. 5  is an isometric, exploded view of the upper spring and the moving unit of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    Embodiments of the disclosure will be described with reference to the drawings. 
         [0012]    Referring to  FIGS. 1-3 , a VCM  10 , according to an exemplary embodiment, includes a case  11 , an upper plate  12 , two elastic plates  13 , a moving unit  14 , a fixing unit  15 , a lower plate  16 , and a conducting pole  17 . 
         [0013]    The case  11  is cuboid and includes an upper cover plate  111  and a sidewall  112  substantially perpendicularly extending downward from peripheral edges of the cover plate  111 . The cover plate  111  and the sidewall  112  cooperatively define a receiving room  113 . The cover plate  111  defines a first through hole  114 , generally at the center thereof, communicating with the receiving room  113 . In this embodiment, the cover plate  111  is generally rectangular, and the sidewall  112  includes four plates extending downwards from the four edges of the cover plate  111  that are connected to each other. 
         [0014]    The upper plate  12  is square and defines a second through hole  121  generally at a central portion thereof. The upper plate  12  defines four first positioning holes  122  at the four corners thereof. 
         [0015]    Each elastic plate  13  is planar and defines a third through hole  130 , generally at the center thereof. The elastic plate  13  includes an outer portion  131 , an inner portion  132 , and an elastic portion  133  connected between the outer portion  131  and the inner portion  132 . The outer portion  131  defines four first connection holes  134  at the four corners thereof. The inner portion  132  includes four blades  135  adjacent to the corners of the outer portion  131 . Each blade  135  defines a second connection hole  136 . 
         [0016]    The moving unit  14  includes a moving barrel  141  and a coil assembly  142 . The moving barrel  141  includes an upper surface  1411 , a lower surface  1412 , and a first outer surface  1413  connected between the upper surface  1411  and the lower surface  1412 . The moving barrel  141  defines a fourth through hole  1414  extending through the upper surface  1411  and the lower surface  1412 . Three first connection poles  1415  extend upward from the upper surface  1411 . The moving barrel  141  defines a blind hole  1416  on the upper surface  1411 . The three first connection poles  1415  and the blind hole  1416  are positioned at the four corners of the upper surface  1411 , generally surrounding the fourth through hole  1414 . Four second connection poles  1417  extend down from the lower surface  1412 , generally at the four corners of the lower surface  1412 . 
         [0017]    The coil assembly  142  includes a coil portion  1421  and a connecting portion  1422 . The coil portion  421  is annular and encircles the first outer surface  1413  of the moving barrel  141 . The connecting portion  1422  is electrically connected to the coil portion  1421 . One end of the connecting portion  1422  facing away the coil portion  1421  is bent into the shape of a hook  1423 . 
         [0018]    The fixing unit  15  includes a fixing frame  151  and a magnet assembly  152 . The fixing frame  151  is cuboid and includes a top surface  1511 , a bottom surface  1512 , and a second outer surface  1513  connected between the top surface  1511  and the bottom surface  1512 . The fixing frame  151  defines a fifth through hole  1514  extending through the top surface  1511  and the bottom surface  1512 . Four first positioning poles  1515  extend up from the top surface  1511 , generally at the four corners of the top surface  1511 . The fixing frame  161  defines four receiving holes  1516  on the second outer surface  1513 . Each of the receiving holes  1516  is generally rectangular and communicates with the fifth through hole  1514 . The fixing frame  151  defines four second positioning holes  1517  in the bottom surface  1512  generally at the four corners of the bottom surface  1512 . 
         [0019]    The magnet assembly  152  includes four generally rectangular magnets  1521  respectively received in the four receiving holes  1516  of the fixing frame  151 . Each magnet  1621  includes a magnetic pole directly facing the second outer surface  1513 , and the other magnetic pole facing in the opposing direction. 
         [0020]    The lower plate  16  is square and centrally defines a sixth through hole  161 . Four second positioning poles  162  extend up from the four corners of the lower plate  16  respectively. 
         [0021]    The conducting pole  17  is made of conductive material, such as copper. The conducting pole  17  includes a first cylinder portion  171  and a second cylinder portion  172  positioned one end of the first cylinder portion  171 . The internal diameter of the second connection hole  136  is slightly less than the external diameter of the first cylinder portion  171  but slightly greater than the external diameter of the second cylinder portion  172 . 
         [0022]    In assembly of the VCM  10 , the moving unit  14  is movably received in the fifth through hole  1514  of the fixing frame  151 . The coil portion  1421  is opposite to the magnet assembly  162 . One of the elastic plates  13  is sandwiched between the upper plate  12  and the fixing frame  151 . The first positioning poles  1515  of the fixing frame  151  are received in the first connection holes  134  of the outer portion  131  and the first positioning holes  122  of the upper plate  12 . The first connection poles  1415  of the moving barrel  141  are received in the second connection holes  136  of the inner portion  132 . The second cylinder portion  172  of the conducting pole  17  penetrates one second connection hole  136  of the inner portion  132  and is received in the blind hole  1416  of the moving barrel  141 . The hook  1423  of the coil assembly  142  is sleeved on the second cylinder portion  172  and locked between the first cylinder portion  171  and the inner portion  132 . The coil portion  1421  is thereby electrically connected to the elastic plate  13  by means of the hook  1423 . 
         [0023]    The other elastic plate  13  is sandwiched between the lower plate  16  and the fixing frame  151 . The second positioning poles  162  of the lower plate  16  are received in the first connection holes  134  of the outer portion  131  and the second positioning holes  1517  of the fixing frame  151 . The second connection poles  1417  of the moving barrel  141  are received in the second connection holes  136  of the inner portion  132 . 
         [0024]    The case  11  receives the upper plate  12 , the elastic plates  13 , the moving unit  14 , the fixing unit  15 , the lower plate  16 , and the conducting pole  17 . In an initial state, the first through hole  114 , the second through hole  121 , the third through hole  130 , the fourth through hole  1414 , the fifth through hole  1514 , the sixth through hole  161  are coaxial with each other. 
         [0025]    During the process of focusing, as the coil assembly  142  is surrounded by the magnet assembly  152 , when the coil assembly  142  is supplied with an electrical current through the elastic plate  13 , the coil assembly  142  experiences a Lorentz force along the optical axis of VCM  10 . Therefore, the moving unit  15  is driven to move along the optical axis to find a position of equilibrium, that is to say, a focus position. As the conducting pole  17  is electrically connected to the elastic plate  13  and the coil assembly  142 , and one end of the conducting pole  17  receiving in the blind hole  1416  of the moving unit  14 , the coil assembly  142  and the elastic plate  13  are firmly connected during the deformation of the elastic plate  13 . 
         [0026]    Particular embodiments are shown and described by way of illustration only. The principles and the features of the present disclosure may be employed in various and numerous embodiments thereof without departing from the scope of the disclosure as claimed. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure.