Abstract:
There is provided a spindle motor including: a sleeve having a protrusion extending in a radial direction; a hub having a main wall part enclosing the sleeve; and a regulating member disposed between the main wall part and the sleeve, wherein the main wall part is provided with an adhesive injection hole so that an adhesive is injected between the regulating member and the main wall part.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of Korean Patent Application No. 10-2011-0137133 filed on Dec. 19, 2011, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a spindle motor, and more particularly, to a spindle motor having a structure capable of improving adhesive force between a hub and a regulating member. 
         [0004]    2. Description of the Related Art 
         [0005]    A hard disk drive (HDD), an information storage device, is a device in which data may be stored on a disk or read therefrom, using a read/write head. The hard disk drive includes a disk driver driving a disk, for example, a small spindle motor. 
         [0006]    The small spindle motor has a fluid dynamic bearing structure for the miniaturization of a motor. In the fluid dynamic bearing structure, a fluid (oil) filled between a shaft, a rotating member, and a sleeve, a fixed member, serves as a bearing in a mechanism structure. 
         [0007]    The spindle motor for the HDD is rotated at high speed. For this reason, the shaft and a hub forming a rotating body may be separated from a base member. 
         [0008]    In order to prevent this, a method of disposing a regulating member between the sleeve and the hub has been considered. However, an adhesive application space may not be able to be secured between the hub and the regulating member, such that it may be difficult to prevent the separation of the hub using the regulating member. 
         [0009]    Meanwhile, there are provided Patent Documents 1 and 2 as the related art associated therewith. 
         [0010]    However, Patent Document 1 discloses that a stopper member 80 is inserted into a hub base 220 in a press-fitting manner and thus, the stopper member 80 and the hub base 220 need to very precisely machined. 
         [0011]    On the other hand, Patent Document 2 discloses a structure in which a hub 22 and an annular member 25 are coupled to each other by an adhesive, but cannot obtain a sufficient degree of adhesive force therebetween due to the absence of a space sufficient to inject an adhesive between the hub 22 and the annular member 25. 
       RELATED ART DOCUMENT 
       [0000]    
       
         (Patent Document 1) KR10-1026013 B1 
         (Patent Document 2) JP2003-333797 A 
       
     
       SUMMARY OF THE INVENTION 
       [0014]    An aspect of the present invention provides a spindle motor having a structure in which a sufficient amount of adhesive may be injected between a hub and a regulating member. 
         [0015]    According to an aspect of the present invention, there is provided a spindle motor, including: a sleeve having a protrusion extending in a radial direction; a hub having a main wall part enclosing the sleeve; and a regulating member disposed between the main wall part and the sleeve, wherein the main wall part is provided with an adhesive injection hole so that an adhesive is injected between the regulating member and the main wall part. 
         [0016]    The regulating member may be provided with a groove connected to the adhesive injection hole. 
         [0017]    The groove may be extendedly formed in a circumferential direction of the regulating member. 
         [0018]    The adhesive injection hole may include a plurality of adhesive injection holes formed to have a predetermined interval therebetween in a circumferential direction of the main wall part. 
         [0019]    The regulating member may be provided with a plurality of grooves connected to the plurality of adhesive injection holes. 
         [0020]    The plurality of grooves may be extendedly formed in the circumferential direction of the regulating member. 
         [0021]    The plurality of grooves may be formed in parallel in the circumferential direction of the regulating member so as not to intersect. 
         [0022]    The plurality of grooves may be connected to each other so that the adhesive injected through the individual adhesive injection holes is uniformly distributed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0023]    The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0024]      FIG. 1  is a cross-sectional view of a spindle motor according to a first embodiment of the present invention; 
           [0025]      FIG. 2  is a cross-sectional view of a spindle motor according to a second embodiment of the present invention; 
           [0026]      FIG. 3  is a cross-sectional view of a spindle motor according to a third embodiment of the present invention; 
           [0027]      FIG. 4  is a perspective view of a regulating member of  FIG. 3  having a first shape; 
           [0028]      FIG. 5  is a perspective view of the regulating member of  FIG. 3  having a second shape; and 
           [0029]      FIG. 6  is a perspective view of the regulating member of  FIG. 3  having a third shape. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0030]    Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
         [0031]    In the drawings, the shapes and dimensions of elements may be exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or like elements. 
         [0032]      FIG. 1  is a cross-sectional view of a spindle motor according to a first embodiment of the present invention,  FIG. 2  is a cross-sectional view of a spindle motor according to a second embodiment of the present invention,  FIG. 3  is a cross-sectional view of a spindle motor according to a third embodiment of the present invention,  FIG. 4  is a perspective view of a regulating member of  FIG. 3  having a first shape,  FIG. 5  is a perspective view of the regulating member of  FIG. 3  having a second shape, and  FIG. 6  is a perspective view of the regulating member of  FIG. 3  having a third shape. 
         [0033]    A spindle motor according to a first embodiment of the present invention will be described with reference to  FIG. 1 . 
         [0034]    A spindle motor  100  according to the first embodiment of the present invention may include a base member  110 , an electromagnet  120 , a sleeve  130 , a shaft  140 , a hub  150 , a permanent magnet  160 , and a regulating member  170 . 
         [0035]    The base member  110  may be a member that is firmly fixed to a body of a hard disk drive device. Therefore, the base member  110  may be formed of the body of the hard disk drive device or may be a part thereof. The base member  110  may be formed of a metal material (for example, an aluminum alloy, or the like). The base member  110  may have a mounting hole  112  in which the sleeve  130  is mounted. 
         [0036]    The mounting hole  112  may have a diameter having the same size as an outer diameter of the sleeve  130  or a diameter having a difference within a predetermined tolerance range. An edge of the mounting hole  112  may be provided with a first main wall part  114  protruded upwardly so as to stably support a circumference of the sleeve  130 . The first main wall part  114  may be provided with a plurality of electromagnets  120 . 
         [0037]    The electromagnets  120  may be disposed in circular form, based on the mounting hole  112 , and may be supplied with current from the outside to generate electromagnetic force. For this purpose, the electromagnets  120  may be configured of a core and a coil. 
         [0038]    The sleeve  130  may be mounted in the mounting hole  112  of the base member  110 . The sleeve  130  is firmly fixed to the base member  110  in a press-fitting manner and may be bonded thereto by an adhesive, or the like, if necessary. The sleeve  130  may have a through hole in which the shaft  140  may be accommodated. In this configuration, the through hole may be larger than an outer diameter of the shaft  140 . That is, an appropriate interval may be maintained between an inner surface  132  of the sleeve  130  and an outer surface of the shaft  140  so that the sleeve  130  and the shaft  140  may serve as a fluid dynamic bearing. 
         [0039]    The sleeve  130  may be provided with a protrusion  134  extending in a radial direction. 
         [0040]    The protrusion  134  may be extendedly formed in a circumferential direction of the sleeve  130  and may be protruded toward a second main wall part  154  from a surface of the sleeve  130 . 
         [0041]    Meanwhile, although not shown, the inner surface  132  of the sleeve  130  may be provided with a comb-shaped fluid dynamic pressure groove so as to generate fluid dynamic pressure at the time of the rotation of the shaft  140 . 
         [0042]    The fluid dynamic pressure groove may have any one of a herringbone shape, a spiral shape, and a helical shape, but the shape of the fluid dynamic pressure groove is not limited thereto so long as it can generate dynamic pressure. 
         [0043]    The shaft  140  may be rotatably mounted on the sleeve  130 . 
         [0044]    The shaft  140  is mounted while penetrating through the sleeve  130 , and may have an extended part  142  extendedly formed outwardly of the sleeve  130  (upwardly, based on  FIG. 1 ). A section of the extended part  142  may be the same as a section of the shaft  140 , but may be different therefrom as in the present embodiment. 
         [0045]    A circumference of the shaft  140  may be provided with a fluid dynamic pressure groove that performs the same or similar function as the fluid dynamic pressure groove formed in the inner surface  132  of the sleeve  130 . Here, similar to the fluid dynamic pressure groove of the sleeve  130 , the fluid dynamic pressure groove may have any one of a herringbone shape, a spiral shape, and a helical shape, but the shape of the fluid dynamic pressure groove is not limited thereto so long as it can generate dynamic pressure. 
         [0046]    The hub  150  may be coupled to the shaft  140 . Specifically, the hub  150  may be coupled to the extended part  142  of the shaft  140  and may be rotated together with the shaft  140 . 
         [0047]    The hub  150  may be provided with a shaft coupling hole  152  into which the shaft  140  is inserted. A size of the shaft coupling hole  152  may be the same as a section size of the extended part  142  within a tolerance range. 
         [0048]    The hub  150  may be provided with the second main wall part  154  and a third main wall part  156 . 
         [0049]    The second main wall part  154  may extend downwardly in the vicinity of the shaft coupling hole  152  of the hub  150 . The second main wall part  154  extending downwardly may enclose the circumference of the sleeve  130 . The second main wall part  154  may suppress a fluid from being leaked to the outside of the sleeve  130 . 
         [0050]    The second main wall part  154  may be provided with an adhesive injection hole  1542 . 
         [0051]    The adhesive injection hole  1542  may penetrate through the second main wall part  154 . In addition, the adhesive injection hole  1542  may extend to the regulating member  170 . Therefore, when an adhesive is injected into the adhesive injection hole  1542 , the adhesive may be injected up to the regulating member  170  disposed inwardly of the second main wall part  154  through the adhesive injection hole  1542 . 
         [0052]    The adhesive injection hole  1542  may have a section size gradually reduced or gradually increased toward the inside of the second main wall part  154  from the outside of the second main wall part  154 . In the former case, the adhesive may be easily injected and in the latter case, the leakage of the injected adhesive may be prevented. 
         [0053]    The adhesive injection holes  1542  may be formed to have a predetermined interval therebetween in the circumferential direction of the second main wall part  154 . In this case, a large amount of adhesive may be injected through the plurality of adhesive injection holes  1542 , such that the degree of adhesive force between the hub  150  and the regulating member  170  may be improved. 
         [0054]    The third main wall part  156  may extend downwardly from an edge of the hub  150 . The third main wall part  156  extending downwardly may enclose the outside of the electromagnet  120 . 
         [0055]    The third main wall part  156  may be provided with the permanent magnet  160 . In addition, the permanent magnet  160  may be disposed on the third main wall part  156  so as to face the electromagnet  120  disposed on the first main wall part  114 . The permanent magnet  160  generates electromagnetic force corresponding to the electromagnet  120 . Therefore, the electromagnet  120  and the permanent magnet  160  form a predetermined magnitude of magnetic field to thereby rotate the shaft  140  and the hub  150 . 
         [0056]    The third main wall part  156  may be provided with a plurality of disks. Here, the disk may be a member that may record and reproduce magnetic information. 
         [0057]    The regulating member  170  may be disposed between the sleeve  130  and the second main wall part  154  of the hub  150 . The regulating member  170  is coupled to the hub  150  to prevent the hub  150  from floating. 
         [0058]    The regulating member  170  may have an annular shape and may have a first radius R 1  and a second radius R 2 . Here, the first radius R 1 , an inner radius of the regulating member  170 , may be larger than a radius R 3  of the sleeve  130  and may be smaller than a radius R 4  of the protrusion  134 . Further, the second radius R 2 , an outer radius of the regulating member  170 , may be larger than the radius R 4  of the protrusion  134  and may be smaller than or equal to an inner radius R 5  of the second main wall part  154 . 
         [0059]    The regulating member  170  is not coupled to the sleeve  130  but may be coupled to the hub  150 . Therefore, the regulating member  170  may be rotated together with the hub  150  when the hub  150  is rotated. However, since the regulating member  170  has the inner radius smaller than the radius of the protrusion  134 , it contacts the protrusion  134  when the hub  150  floats to thereby suppress the hub  150  from floating. 
         [0060]    Meanwhile, the regulating member  170  may form a gap together with the second main wall part  154  of the hub  150 . This may occur due to the machining tolerance of the regulating member  170 . Therefore, if the regulating member  170  and the hub  150  are not firmly bonded to each other by an adhesive, it may be difficult to suppress the floating of the hub  160  using the regulating member  170 . 
         [0061]    However, in the case of the spindle motor  100  according to the embodiment of the present invention, the adhesive may be injected through the adhesive injection hole  1542  to improve the degree of adhesive force between the hub  150  and the regulating member  170 . 
         [0062]    Therefore, in the spindle motor  100  according to the embodiment of the present invention, a z-axis direction location (based on  FIG. 1 ) of the shaft  140  and the hub  150  is not changed due to the regulating member  170  even in the case in which the shaft  140  and the hub  150  are rotated at high speed, such that magnetic information stored on the disk may be accurately read or magnetic information may be accurately recorded on the disk. 
         [0063]    Next, a spindle motor according to a second embodiment of the present invention will be described with reference to  FIG. 2 . 
         [0064]    The spindle motor  100  according to the second embodiment of the present invention may be differentiated from the first embodiment of the present invention in terms of the shape of the regulating member  170 . That is, the regulating member  170  may be provided with a groove  172  as illustrated in  FIG. 2 . 
         [0065]    The groove  172  may be formed in a location facing the adhesive injection hole  1542 . 
         [0066]    Here, the groove  172  may be partially formed on the surface of the regulating member  170  or extendedly formed in the circumferential direction of the regulating member  170 . 
         [0067]    According to the second embodiment, a larger amount of adhesive may be injected between the hub  150  and the regulating member  170  through the groove  172  of the regulating member  170 , thereby improving the degree of adhesive force between the hub  150  and the regulating member  170 . 
         [0068]    Next, a spindle motor according to a third embodiment of the present invention will be described with reference to  FIGS. 3 to 6 . 
         [0069]    The spindle motor  100  according to the third embodiment of the present invention may be differentiated from the foregoing embodiments of the present invention in terms of the shape of the adhesive injection hole  1542  and the regulating member  170 . 
         [0070]    The adhesive injection hole  1542  may be formed in multiple rows. For example, the spindle motor  100  according to the third embodiment of the present invention may have a structure in which first and second adhesive injection holes  1542  and  1544  may be disposed vertically. Here, the individual adhesive injection holes  1542  and  1544  may be formed in the circumferential direction of the second main wall part  154  while having the same interval therebetween or having different intervals therebetween. 
         [0071]    The adhesive injection holes  1542  and  1544  may easily allow the adhesive to be injected therethrough. For example, at least one of the plurality of adhesive injection holes  1542  and  1544  may be used as an outlet for air that is present between the hub  150  and the regulating member  170  during the injection of an adhesive. 
         [0072]    The regulating member  170  may have a plurality of grooves  172  and  174  that correspond to respective adhesive injection holes  1542  and  1544 . 
         [0073]    Here, the grooves  172  and  174  may be formed in parallel with each other in the circumferential direction of the regulating member  170  as illustrated in  FIG. 4 . Alternatively, the grooves  172  and  174  may be formed to intersect in the circumferential direction of the regulating member  170  as illustrated in  FIG. 5 . Alternatively, the grooves  172  and  174  may be formed to be connected by another groove  176  as illustrated in  FIG. 6 . 
         [0074]    As described above, the grooves  172 ,  174 , and  176  having various shapes expand a surface area that may be coated with the adhesive between the hub  150  and the regulating member  170 , thereby improving the degree of adhesive force between the hub  150  and the regulating member  170 . 
         [0075]    In particular, the regulating member  170  illustrated in  FIGS. 5 and 6  may facilitate the injection of the adhesive evenly through one of the adhesive injection holes  1542  and  1544 , since all the grooves  172 ,  174 , and  176  are connected to one another. 
         [0076]    As set forth above, according to the embodiments of the present invention, the degree of adhesive force between the hub and the regulating member can be increased. 
         [0077]    Therefore, according to the embodiments of the present invention, the floating phenomenon of the hub can be effectively suppressed due to the regulating member. 
         [0078]    While the present invention has been shown and described in connection with the embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.