Abstract:
Provided is turntable assembly of a spindle motor. The turntable assembly includes a turntable and a back yoke. The back yoke is installed on the turntable. The turntable includes at least one of a turntable coupling protrusion and a protrusion coupler formed thereon. The back yoke includes at least one of a protrusion coupler and a coupling protrusion formed thereon to face the corresponding components formed on the turntable. The coupling protrusion is inserted in the protrusion coupler to fix the back yoke to the turntable.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a turntable assembly of a spindle motor.  
         [0003]     2. Description of the Related Art  
         [0004]     Prevalent examples of recording media that write and read images, sounds, and other types of data at high density include optical discs, hard discs, cards, and tapes; and of these, optical discs are at the forefront of the mainstream.  
         [0005]     The field of optical discs includes read only memory (ROM) products ranging from laser discs (LD) and compact discs (CD) to digital versatile discs (DVD).  
         [0006]     Optical discs can be generally categorized into CDs and DVDs; CDs can be divided into CD-read only memory (CD-ROM) and CD-Rewritable (CD-RW); and DVDs can be split into DVD-ROMs and DVD-random access memory (RAM).  
         [0007]     Such optical discs have tracks formed to spiral outward from the middle, whereon digital data of a predetermined format is written.  
         [0008]     An optical disc apparatus for reading optical discs has a built-in spindle motor that spins an optical disc at high speed. The optical disc apparatus also includes a built-in actuator, which has a laser diode, lens, beam splitter, photodetector, and other installed optical devices.  
         [0009]     The spindle motor has a turntable, and the turntable has bosses formed thereon. A back yoke passes through the bosses. After the back yoke passes through the bosses, the back yoke and the bosses are stuck together so that the back yoke is fixed on the turntable.  
         [0010]     However, the method (according to the related art) of fixing the back yoke by sticking it to the bosses formed on the turntable employs excessive adhering force, which can damage the bosses.  
         [0011]     Such damage to the bosses reduces the adhering force of the back yoke. If the adhering force of the back yoke is reduced, the back yoke disengages from the table, and is likely to cause a malfunction or failure of the spindle motor.  
         [0012]     Furthermore, the method of adhering the bosses to the turntable results in unevenness of the adhered bosses. Under these conditions, maintenance is not easy.  
       SUMMARY OF THE INVENTION  
       [0013]     Accordingly, the present invention is directed to a turntable assembly of a spindle motor that substantially obviates one or more problems due to limitations and disadvantages of the related art.  
         [0014]     An object of the present invention is to provide a turntable assembly of a spindle motor that has an improved coupling structure for the turntable and back yoke, to furnish a reliable coupling of the turntable and back yoke.  
         [0015]     Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.  
         [0016]     To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a turntable assembly of a spindle motor including: a turntable; and a back yoke installed on the turntable, wherein the turntable includes at least one of a turntable coupling protrusion and a protrusion coupler formed thereon, and the back yoke includes at least one of a protrusion coupler and a coupling protrusion formed thereon to face the at least one turntable coupling protrusion and protrusion coupler formed on the turntable, and the coupling protrusion is inserted in the protrusion coupler, for fixing the back yoke to the turntable.  
         [0017]     In another aspect of the present invention, there is provided a turntable assembly of a spindle motor including: a turntable; a back yoke installed on the turntable; a back yoke coupler formed on the turntable; and a turntable coupler formed on the back yoke and rotatively inserted in the back yoke coupler, for fixing the back yoke to the turntable.  
         [0018]     In yet another aspect of the present invention, there is provided a turntable assembly of a spindle motor including: a turntable; a back yoke installed on the turntable; a back yoke catch protrusion formed on the turntable; and a turntable catch protrusion formed on the back yoke and press-fitted in the back yoke catch protrusion, for fixing the back yoke to the turntable.  
         [0019]     The turntable assembly according to the present invention allows the back yoke to be easily fixed to the turntable using a one-touch operation, without having to perform an adhering process of the two parts. Thus, the turntable assembly is easy to assemble, and the back yoke detaching or disengaging from the turntable while an optical disc is being spun can be prevented.  
         [0020]     It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:  
         [0022]      FIG. 1  is a perspective view of a turntable according to the first embodiment of present invention;  
         [0023]      FIG. 2  is a rear perspective view of a back yoke coupler formed on a turntable according to the first embodiment of the present invention;  
         [0024]      FIG. 3  is a perspective view of a back yoke according to the first embodiment of the present invention;  
         [0025]      FIG. 4  is a perspective view of a back yoke placed on a turntable according to the first embodiment of the present invention;  
         [0026]      FIG. 5  is a perspective view of a back yoke before it is fastened to a turntable according to the first embodiment of the present invention;  
         [0027]      FIG. 6  is a perspective view of a back yoke placed to a turntable according to the first embodiment of the present invention;  
         [0028]      FIG. 7  is a perspective view of the back yoke in  FIG. 6  fixed to the turntable;  
         [0029]      FIG. 8  is a vertical sectional view of a turntable fastened to a spindle motor according to the first embodiment of the present invention;  
         [0030]      FIG. 9  is a perspective view of back yoke according to the second embodiment of the present invention;  
         [0031]      FIG. 10  is a perspective view of a turntable according to the second embodiment of the present invention;  
         [0032]      FIG. 11  is a vertical sectional view showing catch protrusions of a turntable and back yoke before they come into mutual contact, according to the second embodiment of the present invention;  
         [0033]      FIG. 12  is a vertical sectional view showing the catch protrusions of the turntable and back yoke in  FIG. 11  as they are mutually press fitted; and  
         [0034]      FIG. 13  is a vertical sectional view showing the catch protrusions of the turntable and back yoke in  FIG. 12  in a mutually engaged state.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0035]     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.  
         [0036]      FIG. 1  is a perspective view of a turntable according to the first embodiment of present invention,  FIG. 2  is a rear perspective view of a back yoke coupler formed on a turntable according to the first embodiment of the present invention, and  FIG. 3  is a perspective view of a back yoke according to the first embodiment of the present invention.  
         [0037]     Referring to  FIGS. 1 through 3 , a turntable  100  is formed in a discoid shape with a predetermined radius. An optical disc is mounted on the turntable  100 . The bottom portion of the turntable  100  is concaved and is connected to a predetermined portion of the spindle motor. The top portion of the turntable  100  has a flat structure to rest an optical disc on.  
         [0038]     The central portion of the turntable  100  has a through-hole  102  formed therein for inserting and fastening the rotating shaft of the spindle motor. A cylindrical hole forming portion  103  is spaced a predetermined distance radially outward from the through hole  102  on the turntable  100 . A back yoke fastening hole  104  is formed between inside of the hole forming portion  103  and the outer perimeter of the through-hole  102 . A back yoke  200  inserts into the back yoke fastening hole  104 . By inserting the back yoke  200  into the back yoke fastening hole  104 , a loss of a magnetic field emitted by a magnet can be prevented. To fix the back yoke  200  to the back yoke fastening hole  104 , a back yoke coupler  120 , in the form of a coupling protruding portion, is formed.  
         [0039]     The back yoke coupler  120  is formed around the turntable  100  in a circumference arrangement. Specifically, the back yoke coupler  120  is formed as open holes around a circumference of the turntable  100 .  
         [0040]     The back yoke  200  has a through-hole  201  formed in its middle. A body  202  and a connecting portion  203  are alternately formed around the circumference of the through-hole  201 . The body  202  is formed to protrude radially outward a predetermined distance farther than the connecting portion  203 . In this embodiment, the body  202  and the connecting portion  203  are respectively provided in triplicate.  
         [0041]     To allow the back yoke  200  to be assembled to the back yoke fastening hole  104 , the body  202  and its connecting lines may be formed along a regular circumference, and the size of that circumference may be formed to be less by a predetermined amount than that of the back yoke fastening hole  104 .  
         [0042]     The back yoke  200  forms a turntable coupler  204 . In this embodiment, the turntable coupler  204  is a coupling protrusion that protrudes a predetermined distance radially outward from the connecting portion  203  of the back yoke  200 . The turntable coupler  204  is fastened to the back yoke coupler  120 . In detail, the back yoke  200  is first inserted in the back yoke fastening hole  104 , and is then rotated by a predetermined amount. Here, the turntable coupler  204  couples to the back yoke coupler  120  of the turntable  100 , and the back yoke  200  may be fixed to the turntable  100 .  
         [0043]     Referring to  FIG. 2 , an extended portion  121  and a projection  123  are formed on the back yoke coupler  120 . The extended portion  121  extends from the lower surface of the hole forming portion  103 , and the projection  123  protrudes downward from the extended portion  121 . A surface of the turntable coupler  204  on the back yoke  200  catches on a side  124  of the projection  123 . In this way, the back yoke  200  is prevented from disengaging from the turntable  100  when the latter rotates and stops repeatedly.  
         [0044]     The projection  123  is designed not to disengage with the turntable coupler  204  of the back yoke  200  in a direction opposite to the rotating direction of the turntable coupler  204 , in order to couple the turntable coupler  204  with the back yoke coupler  120  of the turntable. Accordingly, the turntable assembly in this embodiment does not use adhesion when assembling the back yoke  200  to the turntable  100 , but instead rotates the back yoke  200  for assembly, so that the assembly process becomes simpler. Also, by not using adhesion, unevenness, assembly defects, etc. caused by adhesion may be obviated.  
         [0045]     The paired turntable and back yoke couplers  204  and  120  are provided in plurality to securely couple the turntable  100  with the back yoke  200 .  
         [0046]      FIG. 4  is a perspective view of a back yoke placed on a turntable according to the first embodiment of the present invention.  
         [0047]     Referring to  FIG. 4 , the turntable coupler  204  formed on the back yoke  200  is has been fastened to the back yoke coupler  120  formed on the turntable  100 , so that the back yoke  200  is assembled with the turntable  100 .  
         [0048]     The turntable coupler  204  formed on the back yoke  200  rotates and inserts at the bottom of the back yoke coupler  120  formed on the turntable  100 , to couple the back yoke  200  to the turntable  100 .  
         [0049]     Here, the turntable coupler  204  of the back yoke  200  catches on the projection formed on the back yoke coupler  120 , in order to prevent disengagement of the back yoke  200  when the turntable  100  repeatedly rotates and stops.  
         [0050]      FIGS. 5 through 7  are perspective views showing the process of fastening the back yoke to the turntable according to the first embodiment of the present invention.  
         [0051]      FIG. 5  is a perspective view of a back yoke before it is fastened to a turntable according to the first embodiment of the present invention,  FIG. 6  is a perspective view of a back yoke placed to a turntable according to the first embodiment of the present invention, and  FIG. 7  is a perspective view of the back yoke in  FIG. 6  fixed to the turntable.  
         [0052]     Referring to  FIGS. 5 through 7  below, a description of the fastening process of a back yoke  200  to a turntable  100  according to the present invention will be given.  
         [0053]     First, referring to  FIG. 5 , the back yoke  200  is aligned above the central area of the turntable  100 . Here, the turntable coupler  204  formed on the back yoke  200  and the back yoke coupler  120  formed on the turntable  100  are disposed oppositely to mutually mesh and fasten.  
         [0054]     Next, Referring to  FIG. 6 , the back yoke  200  is inserted into the back yoke fastening hole  104  formed in the turntable  100 . Then, the turntable coupler  204  of the back yoke  200  is disposed at the bottom of the back yoke coupler  102 , and then the back yoke  200  is rotated.  
         [0055]     When the back yoke  200  is thus rotated, the turntable coupler  204  meshes with the back yoke coupler  120 , so that back yoke  200  and the turntable  100  are completely fixed, as shown in  FIG. 7 . Here, the turntable coupler  204  of the back yoke  200  catches on the projection  123  formed on the back yoke coupler  120  and is completely fixed, so that the back yoke  200  does not disengage even when the turntable  100  repeatedly rotates and stops.  
         [0056]      FIG. 8  is a vertical sectional view of a turntable fastened to a spindle motor according to the first embodiment of the present invention.  
         [0057]     Referring to  FIG. 8 , a spindle motor  100  that rotates an optical disc includes a base plate  150 , a printed circuit board (PCB)  108 , a bearing housing  105 , a shaft holder  115 , a rotating shaft  109 , a rotor  101 , a stator  103 , a coil  140 , an e-ring  114 , a ring slot  113 , and a magnet  106 .  
         [0058]     The turntable  100  forming the back yoke coupler  120  is assembled at the top of the rotating shaft  109 , so that the back yoke  200  may be fastened like a clip; and the back yoke  200  is fastened to the back yoke fastening hole  104  of the turntable  100 .  
         [0059]     The turntable coupler  204  is formed on the back yoke  200  in opposition to the back yoke coupler  120 .  
         [0060]     The above-structured spindle motor  100  fixes an optical disc that is placed atop the turntable  100  using a clamp.  
         [0061]     Here, a magnet is assembled on the back yoke  200  assembled to the turntable  100 , and the back yoke  200  is fastened to strengthen the magnetic field of the magnet.  
         [0062]     The clamp fixed atop the turntable  100  and the magnet on the back yoke  200  function to fix the optical disc in place.  
         [0063]     The back yoke coupler  120  is formed in the back yoke fastening hole  104  of the turntable  100 , and the turntable coupler  204  is formed on the back yoke  200 , so that the back yoke  200  can be fixed to the turntable  100  using a one-touch method, and not an adhering process.  
         [0064]     Below, the second embodiment of the present invention will be described. In the description, elements already described in the first embodiment shall be omitted herefrom and shall be deemed included by said previous descriptions.  
         [0065]      FIG. 9  is a perspective view of back yoke according to the second embodiment of the present invention, and  FIG. 10  is a perspective view of a turntable according to the second embodiment of the present invention.  
         [0066]     Referring to  FIGS. 9 and 10 , a through-hole  201  is formed in the center of the back yoke  200 . The body  202  and the connecting portion  203  are alternately arranged around the circumference of the through-hoe  201 . In this embodiment, the body  202  and the connecting portion  203  are respectively provided in triplicate.  
         [0067]     The turntable  100  includes a back yoke fastening hole  104 , and a hole forming portion  103  for forming the back yoke fastening hole  104 . The inner surface of the hole forming portion  103  includes a back yoke rim  130  that is a coupling portion.  
         [0068]     The back yoke rim  130  is formed around the inner surface of the hole forming portion  103 , and may be in the shape of a ring. The back yoke rim  130  includes a back yoke press-fitting surface  131  that is slanted or rounded by a predetermined amount, and a back yoke catch surface  132  on the rear of the back yoke press-fitting surface  131 .  
         [0069]     A turntable catch protrusion  205 , being a coupling protrusion, is formed to protrude from the outer edge of the body  202  of the back yoke  200 . When the back yoke  200  is inserted in the back yoke fastening hole  104  of the turntable  100 , the turntable catch protrusion  205  catches on the back yoke rim  130 , so that the back yoke  200  is fixed to the turntable  100 .  
         [0070]     The turntable catch protrusion  205  includes a turntable press-fitting surface  207  at a bottom thereof, and a turntable catch surface  206  at a top thereof. When the turntable catch protrusion  205  is coupled to the back yoke catch protrusion  130 , the turntable press-fitting surface  207  contacts the back yoke press-fitting surface  131 , and is then press-fitted therealong. When the peak of the turntable catch protrusion  205  passes over the peak of the back yoke catch protrusion  130 , the turntable catch surface  206  catches on the back yoke catch surface  132 . Then, the back yoke catch protrusion  130  latches to the turntable catch protrusion  205 , so that the turntable catch protrusion  205  does not disengage from the back yoke catch protrusion  130 . The back yoke  200  is thus fixed to the turntable  100 .  
         [0071]     Because the back yoke catch protrusion  130  is annularly formed along the inner surface of the hole forming portion  103 , disengaging of the turntable catch protrusion  205  can be more reliably prevented.  
         [0072]     The turntable catch protrusion  205  may be formed on each of the plurality of bodies  202 . In this case, each of the plurality of turntable catch protrusions  205  acts as a coupling portions for coupling the back yoke  200  to the turntable  100 , so that the back yoke  200  and the turntable are fixed at a plurality of points. Accordingly, the fixing of the back yoke  200  to the turntable  100  is secure.  
         [0073]     The plurality of turntable catch protrusions  205  may form the same angle between one another. In this case, the fixing of the back yoke  200  to the turntable  100  is evenly distributed at points around the circumferences of the two components. Thus, the back yoke  200  is more reliably fixed to the turntable  100 .  
         [0074]      FIGS. 11 through 13  are vertical sectional diagrams showing the coupling process of the turntable catch protrusions to the back yoke catch protrusions, according to the second embodiment of the present invention.  
         [0075]      FIG. 11  is a vertical sectional view showing catch protrusions of a turntable and back yoke before they come into mutual contact, according to the second embodiment of the present invention,  FIG. 12  is a vertical sectional view showing the catch protrusions of the turntable and back yoke in  FIG. 11  as they are mutually press fitted, and  FIG. 13  is a vertical sectional view showing the catch protrusions of the turntable and back yoke in  FIG. 12  in a mutually engaged state.  
         [0076]     Below, the coupling process of the turntable catch protrusions to the back yoke coupling protrusions, according to the second embodiment of the present invention, will be described with reference to  FIGS. 11 through 13 .  
         [0077]     First, referring to  FIG. 11 , the back yoke  200  is inserted in the back yoke fastening hole  104  of the turntable  100 , and then the turntable catch protrusions  205  are inserted into the back yoke insert fastening hole  104 .  
         [0078]     Then, referring to  FIG. 12 , the back yoke  200  is pressed downward, so that the turntable catch protrusions  205  are also pressed downward. After the pressing down of these parts, the turntable press-fitting surfaces  207  contact the back yoke press-fitting surfaces  131 . In this state, when external force is applied, the turntable press-fitting surfaces  207  and the back yoke press-fitting surfaces  131  are press-fitted together, so that the turntable catch protrusions  205  descend.  
         [0079]     After the descending, the peaks of the turntable catch protrusions  205  pass the peaks of the back yoke catch protrusions  130 , so that the turntable catch protrusions are positioned below the back yoke catch protrusions  130 . In this state, the turntable catch surfaces  206  and the back yoke catch surfaces  132  contact one another. Then, disengaging of the turntable catch protrusions  205  can be prevented, and the back yoke  200  can be fixed in the back yoke fastening hole  104  of the turntable  100 .  
         [0080]     The present invention provides a turntable assembly that allows easy fastening of the back yoke to the turntable without adhering the two components. Thus, the turntable assembly can be easily assembled, and disconnecting or disengaging of the back yoke from the turntable during the rotation of an optical disc.  
         [0081]     It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.