Abstract:
Disclosed herein is a spindle motor including: a shaft insertedly mounted so as to be perpendicular to an upper side portion; a sleeve receiving the shaft therein to thereby rotatably support the shaft and forming a space between the sleeve and the shaft to thereby be spaced apart from the shaft so as not to contact the shaft; a holder having the sleeve mounted in an inner portion thereof and having a lower portion mounted on an upper portion of a plate; and the plate integrally supporting lower portions of the shaft and the sleeve and including connecting parts connecting the holder and the plate to each other and fixing parts fixing positions of the holder and the plate so that a lower surface of the holder is coupled thereto.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2011-0085972, filed on Aug. 26, 2011, entitled “Spindle Motor”, which is hereby incorporated by reference in its entirety into this application. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to a spindle motor. 
         [0004]    2. Description of the Related Art 
         [0005]    The present invention relates to a motor and an optical disk drive using the same, and more particularly, to a motor having an improved coupling structure between a holder and a base plate and an optical disk drive using the same. 
         [0006]    In the spindle motor according to the prior art, a circuit substrate is mounted on a base plate, and a holder is inserted into a hole formed at a central portion of the base plate to thereby be fixed to the base plate, or the like. In addition, a lower surface of the holder is connected to a separate support plate. 
         [0007]    The holder according to the prior art is formed through cutting. As a material of the holder, expensive brass has been mainly used. 
         [0008]    Therefore, research into a method capable of reducing a cost at the time of manufacturing a motor has been urgently demanded. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention has been made in an effort to provide a spindle motor having an improved coupling structure to reduce a cost. 
         [0010]    According to a preferred embodiment of the present invention, there is provided a spindle motor including: a shaft insertedly mounted so as to be perpendicular to an upper side portion; a sleeve receiving the shaft therein to thereby rotatably support the shaft and forming a space between the sleeve and the shaft to thereby be spaced apart from the shaft so as not to contact the shaft; a holder having the sleeve mounted in an inner portion thereof and having a lower portion mounted on an upper portion of a plate; and the plate integrally supporting lower portions of the shaft and the sleeve and including connecting parts connecting the holder and the plate to each other and fixing parts fixing positions of the holder and the plate so that a lower surface of the holder is coupled thereto. 
         [0011]    The spindle motor may further include a thrust plate mounted on the plate and under the sleeve. 
         [0012]    The holder may have the sleeve mounted in the inner portion thereof, an armature mounted on an outer diameter thereof, and a lower portion formed to be stepped so as to be coupled to the plate. 
         [0013]    At least one connecting part and fixing part may be formed. 
         [0014]    The fixing part may be disposed between the connecting parts. 
         [0015]    Each of the connecting part and the fixing part may be finely adjusted. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a partial cross-sectional view of a spindle motor according to a preferred embodiment of the present invention; and 
           [0017]      FIG. 2  is a partially enlarged view of the spindle motor according to the preferred embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    Various objects, advantages and features of the invention will become apparent from the following description of embodiments with reference to the accompanying drawings. 
         [0019]    The terms and words used in the present specification and claims should not be interpreted as being limited to typical meanings or dictionary definitions, but should be interpreted as having meanings and concepts relevant to the technical scope of the present invention based on the rule according to which an inventor can appropriately define the concept of the term to describe most appropriately the best method he or she knows for carrying out the invention. 
         [0020]    The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. In the specification, in adding reference numerals to components throughout the drawings, it is to be noted that like reference numerals designate like components even though components are shown in different drawings. Further, when it is determined that the detailed description of the known art related to the present invention may obscure the gist of the present invention, the detailed description thereof will be omitted. 
         [0021]    Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
         [0022]      FIG. 1  is a partial cross-sectional view of a spindle motor  100  according to a preferred embodiment of the present invention; and  FIG. 2  is a partially enlarged view of the spindle motor  100  according to the preferred embodiment of the present invention. 
         [0023]    As shown in  FIG. 1 , the spindle motor  100  according to the preferred embodiment of the present invention includes a plate  110 , a holder  120 , a sleeve  130 , an armature  140 , a shaft  150 , a thrust plate  160 , and a rotor case  170 . 
         [0024]    The plate  110 , which is to fixedly support the entire spindle motor  100 , is fixedly mounted in a device such as an optical disk drive, or the like, having the spindle motor  100  mounted therein. Here, the plate  110  is made of a light weight material such as an aluminum plate, an aluminum alloy plate, or the like. However, the plate  110  may also be made of a steel plate. 
         [0025]    In addition, the plate  110  includes a coupling part  111  protruded therefrom, wherein the coupling part  111  includes the holder  120  coupled thereto. 
         [0026]    The coupling part  111  includes a connecting part  111   a  and a fixing part  111   b  so that the holder  120  is coupled and fixed to an upper surface of the plate  110 . 
         [0027]    The connecting part  111   a  and the fixing part  111   b  are shown in  FIG. 2  and will be described below in detail with reference to  FIG. 2 . 
         [0028]    The holder  120 , which is to receive the sleeve  130  in an inner portion thereof, is fixedly coupled to the coupling part  111  of the plate  110 . 
         [0029]    The holder  120  includes a cylindrical body part (not shown) closely adhered to an outer peripheral surface of the sleeve  130  to thereby support the sleeve  130  and a plate support part (not shown) formed to be stepped with respect to the body part (not shown) and support an upper portion of the plate  110 . 
         [0030]    The sleeve  130 , which is to rotatably support the shaft  150 , generally has a hollow cylindrical shape and includes an inner diameter part (not shown) facing the shaft  150  and a lower surface (not shown) facing the thrust plate  160 . 
         [0031]    The armature  140 , which is to form an electric field by receiving external power in order to rotate the rotor case  170  having an optical disk or a magnetic disk mounted thereon, is configured of a core  141  formed by stacking a plurality of sheets of thin metal plates and a coil  142  wound many times around the core  141 . 
         [0032]    The core  141  is fixedly mounted on an outer peripheral surface of the holder and the coil  142  is wound around the core  141 . Here, the coil  142  forms an electric field by current applied from the outside thereto to thereby rotate the rotor case  170  by electromagnetic force formed between the coil  142  and a magnet  171  of the rotor case  170 . 
         [0033]    The shaft  150 , which is to support the rotor case  170  in an axial direction, is inserted into the sleeve  130  and is rotatably supported by the sleeve  130 . 
         [0034]    Meanwhile, the shaft  150  includes the thrust plate  160  disposed on a lower portion thereof, wherein the thrust plate  160  is fixed to the plate  110  disposed under the sleeve  130 . Separate laser welding, or the like, may be performed in order to fix the thrust plate  160  to the plate  110 . Unlike this, the thrust plate  160  and the plate  110  may be coupled to each other through press-fitting by applying a predetermined pressure to the thrust plate  160 . 
         [0035]    The rotor case  170 , which is to have an optical disk or a magnetic disk (not shown) mounted thereon and rotate the optical disk or the magnetic disk, includes a disk part (not shown) having the shaft  150  fixedly mounted thereto and an annular edge part (not shown) extended from a distal end of the disk part. 
         [0036]    The disk part (not shown) includes the shaft  150  fixedly and insertedly coupled to a central portion thereof, and the edge part (not shown) is extended in the axial direction of the shaft  150  so that an inner peripheral surface thereof faces the armature  140  and includes the magnet  171  fixedly mounted to the inner peripheral surface thereof, wherein the magnet  171  forms a magnetic field so as to generate electromagnetic force with the electric field formed in the coil  142 . 
         [0037]      FIG. 2  is a partially enlarged view of a spindle motor  100  according to a preferred embodiment of the present invention. 
         [0038]      FIG. 2  shows that the connecting part  111   a  connecting the holder  120  to the upper surface of the plate  110  when the holder  120  is coupled to the plate  110  and the fixing part  111   b  fixing the plate  110  and the holder  120  to each other are formed. 
         [0039]    Here, a lower surface of the holder  120  mounted on the upper portion of the plate  110  is extended, and the plate  110  is provided with each of the connecting part  111   a  and the fixing part  111   b  so as to be coupled to the lower surface of the holder  120 . 
         [0040]    The number of connecting parts  111   a  and fixing parts  111   b  may be at least one, and the fixing part  111   b  may be formed between the connecting parts  111   a.  The connecting part  111   a  may be connected by various methods and may also be connected by a screw thread, and the fixing part  111   b  may be fixed by various methods and may be fixed by a method such as a press-fitting method, or the like. 
         [0041]    Here, positions at which the connecting part  111   a  and the fixing part  111   b  are disposed are not limited. For example, the fixing part  111   b  may also be formed between the connecting parts  111   a.    
         [0042]    In addition, since the plate  110  is formed to be stepped to thereby support the lower portions of the shaft  150  and the thrust plate  160  and the lower portion of the holder  120 , a separate support plate is not required. 
         [0043]    The plate  110  with which a support plate is formed integrally is used without a separate support plate and the plate  110  and the holder  120  are provided with the connecting part  111   a  and the fixing part  111   b,  thereby making it possible to control reaction force generated at the time of connecting the plate  110  and the holder  120  to each other. 
         [0044]    In addition, each of the connecting part  111   a  and the fixing part  111   b  of the plate  110  is finely adjusted differently, thereby making it possible to more firmly and precisely connect the holder  120  to the plate  110 . 
         [0045]    As set forth above, with the spindle motor  100  according to the preferred embodiment of the present invention, each of the connecting part  111   a  and the fixing part  111   b  is formed so that the plate  110  and the holder  120  are coupled to each other, thereby making it possible to control reaction force generated at the time of connecting the plate  110  and the holder  120  to each other. 
         [0046]    In addition, since the holder according to the prior art is formed through cutting, expensive brass is mainly used as a material of the holder. On the other hand, according to the preferred embodiment of the present invention, since the expensive brass need not be used, a cost is significantly reduced. 
         [0047]    Furthermore, since each of the connecting part  111   a  and the fixing part  111   b  of the plate  110  may be finely adjusted differently, the holder  120  may be more firmly and precisely connected to the plate  110 . 
         [0048]    Although the embodiment of the present invention has been disclosed for illustrative purposes, it will be appreciated that a spindle motor according to the invention is not limited thereby, and those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention. 
         [0049]    Accordingly, such modifications, additions and substitutions should also be understood to fall within the scope of the present invention.