Abstract:
Disclosed are a slider for a memory device and a hard memory device having the same. The slider for a memory device includes a slider body configured to fly over the surface of a medium at a particular height; and a reverse flow preventing unit disposed at part of the slider body adjacent to a trailing edge of the slider body and configured to prevent a reverse flow of air between the medium and the slider body.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2011-0029046, filed with the Korean Intellectual Property Office on Mar. 30, 2011, the disclosure of which is incorporated herein by reference in its entirety. 
       FIELD OF THE DISCLOSURE 
       [0002]    Embodiments of the present disclosure relate to a slider for a hard disc drive (HDD) and an HDD having the same, and particularly, to a slider for an HDD capable of preventing a reverse flow of air occurring along an Air Bearing Surface (ABS) of the slider, and an HDD having the same. 
       BACKGROUND OF THE DISCLOSURE 
       [0003]    A hard disc drive (HDD) is a device to reproduce data recorded on a disc or records data onto the disc using a read/write head. The hard disc drive is being widely used as an auxiliary memory device of a computer system owing to its capability to access a great amount of data at a high speed. 
         [0004]    Recently, the HDD has high capability owing to its increased Tracks Per Inch (TPI) and Bits Per Inch (BPI). As the HDD has high capability, the read/write head has a smaller size and a gap between a slider flying above the surface of a disc and the disc becomes narrower. 
         [0005]    Especially, in the case of an HDD applying Thermal Fly height Control (TFC) technique, the slider and the disc maintains a gap of 1-5 nanometers (nm) therebetween. 
         [0006]    However, if the slider flies while maintaining a smaller gap from the disc, lubricant on the surface of the disc may be transferred to the slider due to a reverse flow of air. 
         [0007]      FIG. 1  is a view showing a lubricant transfer phenomenon occurring on a slider of a hard disc drive (HDD) in accordance with the related art, and  FIG. 2  is a view showing an air flow inside the slider of  FIG. 1 . 
         [0008]    As shown, when the disc  200  rotates, air  202  is introduced into space between the disc and the slider  204  along a rotation direction of the disc  200 , thereby flying the slider  204 . The air has deceased pressure at a trailing edge (TE) thereof. As a result, a reverse flow of the air  206  occurs along the TE and an Air Bearing Surface (ABS). 
         [0009]    The reverse flow transfers lubricant  208  which is on the surface of the disc  200  to the slider. This may cause the lubricant to be accumulated on the slider or the disc, and cause a difficulty in maintaining the gap between the slider and the disc. As a result, the HDD may not smoothly operate. 
         [0010]    In the related art, the reverse flow is prevented by changing a shape of the slider, or by forming a lube dam on the ABS. 
         [0011]    However, the related method may have the following problems. That is, the slider has a restricted shape, and flying performance of the slider on the ABS is lowered. 
         [0012]    The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. 
       SUMMARY 
       [0013]    This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
         [0014]    Therefore, an aspect of the disclosure embodiments is to provide a slider for a hard disc drive (HDD) capable of preventing a reverse flow of air between the slider and a disc, and an HDD having the same. 
         [0015]    To achieve these and other advantages as embodied and broadly described herein, there is provided a slider for a hard disc drive (HDD), the slider comprising: a slider body having a read/write head mounted thereon, the read/write head for recording data on a disc or reading out data on the disc while flying over the surface of the disc at a particular height; and a reverse flow preventing unit disposed at part of the slider body adjacent to the read/write head, and configured to prevent a reverse flow of air between the disc and the slider body. 
         [0016]    The reverse flow preventing unit may include at least one through hole penetratingly formed at part of the slider body, such that external air is mixed with air flowing between the slider body and the disc. 
         [0017]    The through hole may include an inlet through which external air is introduced, and an outlet through which the external air is exhausted out. 
         [0018]    The inlet may be formed on an upper surface of the slider body. 
         [0019]    The outlet may be formed on a front surface of a trailing edge of the slider body, which is close to the read/write head. 
         [0020]    The inlet may have a diameter larger than that of the outlet. 
         [0021]    The through hole may be inclined. 
         [0022]    The slider may further comprise a stepped portion protruding from the slider body in a stair-step shape, on the front surface of the trailing edge of the slider body adjacent to the read/write head, and configured to prevent collision between the slider body and the disc, and to maintain a small gap between the read/write head and the disc. 
         [0023]    The reverse flow preventing unit may include a through hole penetratingly formed at part of the slider body. The through hole may include an inlet through which external air is introduced, and an outlet through which the external air is exhausted out. The outlet may be penetratingly formed at the slider body below the stepped portion. 
         [0024]    The inlet may be formed on an upper surface of the slider body. 
         [0025]    To achieve these and other advantages as embodied and broadly described herein, there is also provided a hard disc drive (HDD) comprising: a disc on which data is recorded and read out; and a slider including a slider body and a reverse flow preventing unit, the slider body having a read/write head mounted thereon, the read/write head for recording data onto the disc or reading out data on the disc while flying above the surface of the disc at a particular height, the reverse flow preventing unit disposed at part of the slider body adjacent to the read/write head and configured to prevent a reverse flow of air between the disc and the slider body. 
         [0026]    The reverse flow preventing unit may include at least one through hole penetratingly formed at part of the slider body, such that external air is mixed with air flowing between the slider body and the disc. 
         [0027]    The through hole may include an inlet through which external air is introduced, and an outlet through which the external air is exhausted out. 
         [0028]    The inlet may be formed on an upper surface of the slider body. 
         [0029]    The outlet may be formed on a front surface of a trailing edge of the slider body, which is close to the read/write head. 
         [0030]    The inlet may have a diameter larger than that of the outlet. 
         [0031]    The through hole may be inclined. 
         [0032]    The HDD may further comprise a stepped portion protruding from the slider body in a stair-step shape, on the front surface of the trailing edge of the slider body adjacent to the read/write head, and configured to prevent collision between the slider body and the disc, and to maintain a small gap between the read/write head and the disc. 
         [0033]    The reverse flow preventing unit may include a through hole penetratingly formed at part of the slider body. The through hole may include an inlet through which external air is introduced, and an outlet through which the external air is exhausted out. The outlet may be penetratingly formed at the slider body below the stepped portion. 
         [0034]    The inlet may be formed on an upper surface of the slider body. 
         [0035]    In the present disclosure, owing to the reverse flow preventing unit formed at the slider, a reverse flow of air between the slider and the disc may be prevented. 
         [0036]    Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating some embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the scope of the disclosure will become apparent to those skilled in the art from the detailed description. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0037]    The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments and together with the description serve to explain the principles of the disclosure. 
           [0038]    In the drawings: 
           [0039]      FIG. 1  is a view showing a lubricant transfer phenomenon occurring on a slider of a hard disc drive (HDD) in accordance with the related art; 
           [0040]      FIG. 2  is a view showing an air flow inside the slider of  FIG. 1 ; 
           [0041]      FIG. 3  is a partial disassembled perspective view of an HDD according to a first embodiment of the present disclosure; 
           [0042]      FIG. 4  is an enlarged perspective view of a Head Gimbal Assembly (HGA) of  FIG. 3 ; 
           [0043]      FIG. 5  is a side sectional view of  FIG. 4 ; 
           [0044]      FIG. 6  is a schematic side sectional view of a slider and a disc for an HDD according to a first embodiment of the present disclosure; 
           [0045]      FIG. 7  is a view for explaining an air flow inside the slider of  FIG. 6 ; and 
           [0046]      FIG. 8  is a frontal view of the slider of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION 
       [0047]    Description will now be given in detail of the exemplary embodiments, with reference to the accompanying drawings. For the sake of brevity with reference to the drawings, the same or equivalent components will be provided with the same reference numbers, and a detailed description thereof will not be repeated. 
         [0048]      FIG. 3  is a partial disassembled perspective view of an HDD according to a first embodiment of the present disclosure. 
         [0049]    Referring to  FIG. 3 , a hard disc drive (HDD)  1  according to a first embodiment of the present disclosure comprises a disc pack  10  having at least one disc  11  onto which data is recorded, a Head Stack Assembly (HSA)  30  including a Head Gimbal Assembly (HGA)  20  having a read/write head  21  mounted thereon, the read/write head  21  for recording data onto the disc  11  or reading out data on the disc  11 , a voice coil motor (VCM)  40 , a Printed Circuit Board Assembly (PCBA)  50 , a base  60  onto which the components are assembled, and a cover  70  for covering the base  60 . 
         [0050]    The disc pack  10  is an assembly of media onto which data is recorded, which is implemented by fixing a plurality of circular discs  11  to the same shaft. In this embodiment, the disc pack  10  includes a plurality of circular discs  11 , a shaft  13  serving as a pivoting center, a spindle motor hub (not shown) rotating together with the disc  11  and supporting the disc  11 , a spindle motor (not shown) for rotating the spindle motor hub, a clamp  14  coupled to an upper part of the spindle motor hub, and a clamp screw  15  for pressing the clamp  14  so that the disc  11  can be fixed to the spindle motor hub. Under this configuration, the disc  11  can rotate to generate a force to fly the read/write head  21  above the surface of the disc  11 . 
         [0051]    The Printed Circuit Board Assembly (PCBA)  50  includes a Printed Circuit Board (PCB, not shown) coupled to a rear surface of the base  60 , a Flexible Printed Circuit Board (FPCB) mounted to an upper surface of the base  60  close to the HSA  30 , and configured to electrically connect the HSA  30  and the PCB with each other, and a PCB connector  51  disposed at one side of the PCB. A plurality of chips (not shown) configured to control the disc packs  10 , the HSA  30 , the VCM  40 , etc. are mounted to the PCB. The PCB transmits and receives signals to/from the outside through the PCB connector  51 . 
         [0052]    The VCM  40  is a type of driving motor for driving an actuator arm  33  of the HSA  30  in a particular direction, so that the read/write head  21  can be moved to a desired position on the disc  11 . The VCM  41  includes a VCM block  41  having a magnet (not shown), and a VCM coil (not shown) mounted to a bobbin (not shown). 
         [0053]    The VCM  40  is operated according to Fleming&#39;s left-hand rule, whereby an electromagnetic force is generated when current flows in a conductive body existing in a magnetic field. More specifically, the VCM  40  pivots a bobbin upon applying a force to the bobbin by applying current to a VCM coil located between magnets. Under this configuration, the actuator arm  33  rotates in a particular direction, and the read/write head  21  mounted to the end of the actuator arm  33  moves on the rotating disc  11  in a radius direction. The read/write head  21  searches one or more tracks while moving on the disc  11  and accesses information, thereby recording data onto the disc  11  or reading out data on the disc  11 . 
         [0054]    The HSA  30  includes a Head Gimbal Assembly (HGA)  20  having the read/write head  21  mounted thereon, the read/write head  21  for recording data onto the disc  11  or reading out data on the disc  11 , an actuator arm  33  which moves or pivots with respect to the disc  11  around a pivot shaft  32  as a pivoting center so that the read/write head  21  may access data on the disc  11 , a pivot shaft holder  34  for rotatably supporting the pivot shaft  32 , and to which the actuator arm  33  is coupled for support, and a bobbin (not shown) disposed at the pivot shaft holder  34  in the opposite direction to the actuator arm  33 , and on which a voice coil motor (VCM) coil (not shown) is wound so as to be located between magnets (not shown) of the VCM  40 . 
         [0055]      FIG. 4  is an enlarged perspective view of a Head Gimbal Assembly (HGA) of  FIG. 3 , and  FIG. 5  is a side sectional view of  FIG. 4 . 
         [0056]    Referring to  FIGS. 4 and 5 , the Head Gimbal Assembly (HGA)  20  includes the read/write head  21  for recording data onto the disc  11  or reading out data on the disc  11 , a slider  100  having the read/write head  21  mounted thereon, a flexure  22  to which the slider  100  is coupled, and a suspension  23  coupled to one end of the actuator arm  33 . 
         [0057]    The read/write head  21  is provided on a bottom surface of the slider  100 , and records data onto the disc  11  or reads out data on the disc  11  by sensing a magnetic field generated on the surface of the disc  11 , or by magnetizing the surface of the disc  11 . The read/write head  21  includes a write head for magnetizing the disc  11 , and a read head for sensing a magnetic field of the disc  11 . 
         [0058]    The flexure  22 , part to which the slider  100  is coupled, has a rear end portion coupled to one surface of the suspension  23 , i.e., a surface facing the disc  11 . To a front end portion of the flexure  22 , the slider  100  having the read/write head  21  mounted thereon is coupled. In order to restrict an up-down moving distance of the flexure  22 , a dimple  23   a  and a limiter (not shown) are provided at the suspension  23 . 
         [0059]    The dimple  23   a  is configured to restrict a spaced distance of the slider  100  from the disc  11 , thereby preventing lowering of reliability when recording data onto the disc  11  or reading out data on the disc  11  by the read/write head  21 . And, the limiter (not shown) is configured to prevent excessive spacing of the flexure  22  from the suspension  23 , thereby preventing interference between the read/write head  21  and the disc  11 . 
         [0060]    The suspension  23 , part to which the flexure  22  is coupled, may allow the slider  100  to move close to or far from the surface of the disc  11  in an elastically biased manner. 
         [0061]    Hereinafter, the slider  100  for an HDD according to a first embodiment of the present disclosure will be explained in more details. 
         [0062]      FIG. 6  is a schematic side sectional view of a slider and a disc for an HDD according to a first embodiment of the present disclosure,  FIG. 7  is a view for explaining an air flow inside the slider of  FIG. 6 , and  FIG. 8  is a frontal view of the slider of  FIG. 7 . 
         [0063]    Referring to  FIGS. 6 to 8 , the slider  100  for an HDD according to a first embodiment includes a slider body  110  having a read/write head  21  mounted thereon, the read/write head  21  for recording data onto the disc  11  or reading out data on the disc  11  while flying above the surface of the disc  11  at a particular height, and a reverse flow preventing unit  120  disposed at part of the slider body  110  close to the read/write head  21  and configured to prevent a reverse flow of air between the disk  11  and the slider body  110 . 
         [0064]    The slider body  110  may be formed in a thin cube shape. A front surface of the slider body  110  in a rotation direction of the disc  11  is called ‘Leading Edge’  112 , whereas a rear surface of the slider body  110  where the read/write head  21  is mounted is called ‘Trailing Edge’  111 . A lower surface of the slider body  110  is called ‘Air Bearing Surface’ (ABS)  113 , and may have various patterns for flying of the slider  100 . 
         [0065]    When the disc  11  rotates at a high speed, a force to fly the slider body  110  is generated due to friction between the surface of the disc  11  and air. The flying force allows the slider body  110  to fly in a state where the read/write head  21  is mounted thereto. As a result, as shown in  FIG. 5 , the read/write head  21  records data onto the disc  11  or reads out data on the disc  11  while maintaining the flying state above a data region of the disc  11 , at a height where the flying force is balanced with an elastic force by the suspension  23 . 
         [0066]    The reverse flow preventing unit  120  includes a through hole  121  penetratingly formed at part of the slider body  110  so that external air can be mixed with air flowing between the slider body  110  and the disc  11 . 
         [0067]    Referring to  FIGS. 6 to 8 , the through hole  121  includes an inlet  121   a  through which external air is introduced, and an outlet through which the external air is exhausted out. More specifically, the inlet  121   a  is formed on an upper surface of the slider body  110 , and through which external air above the slider body  110  is introduced into the through hole  121  of the reverse flow preventing unit  120 . And, the outlet  121   b  is formed on a front surface of the trailing edge (TE)  111  of the slider body  110  where a reverse flow of air occurs, and through which the external air introduced into the through hole  121  via the inlet  121   a  is exhausted. 
         [0068]    The inlet  121   a  of the through hole  121  is formed to have a diameter larger than that of the outlet  121   b . This may increase an introduction amount of external air above the slider body  110 , into the through hole  121  through the inlet  121   a.    
         [0069]    The through hole  121  is inclined between the inlet  121   a  and the outlet  121   b  so that introduced external air can smoothly move without any resistance. 
         [0070]    The slider  100  for an HDD according to the present disclosure further includes a stepped portion  130  protruding from the slider body  110  in a stair-step shape, on the front surface of the trailing edge (TE)  111  of the slider body  110  close to the read/write head  21 , and configured to prevent collision between the slider  100  and the disc  11  when the slider  100  has a constant pitch angle, and to maintain a small gap between the read/write head  21  and the disc  11 . 
         [0071]    The stepped portion  130  is formed as read/write sensors (not shown) of the read/write head  21  are laminated on each other, and is disposed on the front surface of the TE  111  of the slider body  110  close to the read/write head  21 . 
         [0072]    Under the configuration of this embodiment, air pressure is reduced below the stepped portion  130  stepped with respect to the slider body  110 , causing a reverse flow of air. To prevent this, the outlet  121   b  of the through hole  121  is penetratingly formed at the slider body  110  below the stepped portion  130 . As a result, a reverse flow of air occurring between the slider body  110  and the disc  11  can be prevented. 
         [0073]    In this embodiment, when the HDD  1  operates, a reverse flow of air occurring between the slider body  110  and the disc  11  can be prevented. This can allow the read/write head  21  to maintain an optimum flying height. 
         [0074]    In this embodiment, a single through hole  121  is penetratingly formed at the slider body  110 . However, the present disclosure is not limited to this. That is, a plurality of through holes  121  may be formed to prevent a reverse flow of air occurring on the bottom surface of the slider body  110 . For instance, the reverse flow preventing unit  120  may be implemented as two through holes  121 . 
         [0075]    In this embodiment, the inlet  121   a  of the through hole  121  is formed at an upper part of the slider body  110 . However, the present disclosure is not limited to this. That is, the inlet  121   a  may be formed at any position where external air unrelated to generation of a flying force of the slider  100  can be introduced. For instance, the inlet  121   a  of the through hole  121  may be formed on a side surface of the slider body  110 . 
         [0076]    In this embodiment, the slider  100  includes the stepped portion  130 . However, the present disclosure is not limited to this. That is, the reverse flow preventing unit  120  may be also applied to the slider  100  not having the stepped portion  130 . 
         [0077]    The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the inventive concepts herein. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments. 
         [0078]    As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.