Patent Publication Number: US-2007097545-A1

Title: Disk damper and hard disk drive having the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application claims the benefit of Korean Patent Application No. 10-2005-0104930, filed on Nov. 3, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present general inventive concept relates to a hard disk drive (HDD), and more particularly, to a disk damper which reduces vibration of a head stack assembly (HSA) by air flow caused by rotation of a disk, and a HDD having the same.  
      2. Description of the Related Art  
      A hard disk drive (HDD) is an example of an auxiliary memory used in computers, MP3 players, mobile phones, and so on to record data on a disk-shaped data storing medium or to read the data recorded using a slider with a magnetic head.  
       FIG. 1  is a plan view illustrating an example of a conventional HDD.  
      With reference to  FIG. 1 , the conventional HDD  10  includes a disk  20  as a data storing medium, a spindle motor  15  rotating the disk  20  at high speed, and a head stack assembly (has)  25  in a housing including a base  11  and a cover (not shown) coupled to the base  11 . A slider  27  having a magnetic head (not shown) for recording and reading data is mounted on the front end of the HSA  25 , and the HSA  25  records data on the disk  20  or reads the data recorded on the disk  20  by moving the slider  27  to a predetermined position on the disk  20 .  
      When the disk  20  rotates at high speed on the base  11 , a lift force acts on the slider  27 . The slider  27  floats at a predetermined height where the lift force is equal to the elastic pressing force of the front end of the HSA  25  toward the disk  20 . The magnetic head (not shown) on the slider  27  floating at the predetermined height reproduces or records data on the disk  20 .  
      The HDD  10  includes a disk damper  30  controlling the vibration of the disk  20  caused by the high-speed rotation of the disk  20 . The disk damper  30  has an alphabet character “C” shape so as not to interrupt the movement of the HSA  25 . When a plurality of disks  20  are included in the HDD  10 , the disk damper  30  is inserted, at a predetermined space, between the disks  20  so that the disks  20  do not collide with each other. When a single disk  20  is included in the HDD  10 , the disk damper  30  is inserted between the cover (not shown) and the disk  20  so that the cover does not collide with the disk  20 .  
      To connect a flexible printed circuit (FPC) connected with the HSA  25  to a main circuit substrate (not shown) under the base  11 , a FPC bracket  35  is operatively positioned on the base  11 . To filter alien substances, such as particles, from the air inside the HDD  10 , a circulating filter  40  is operatively positioned diagonally relative to the FPC bracket  35 .  
      In the conventional HDD  10 , the air flow flows counter-clockwise along the disk  20  rotating counter-clockwise and flows into a front end  31  of the disk damper  30 , and it flows between the disk damper  30  and the disk  20  and flows out through the rear end  32  of the disk damper  30 . When the air flow flowing out through a rear end  32  of the disk damper  30  exits the disk damper  30 , the width of the air flow suddenly increases, and the flow disturbance of the air at a wake region T adjacent to the rear end  32  increases. Thus, there is a problem of increasing the vibration of the HSA  25  due to the increase in the flow disturbance.  
      Moreover, since the air flow toward the circulating filter  40  is controlled by the disk damper  30 , there is another problem of reducing the particles-collecting efficiency by the circulating filter  40 .  
     SUMMARY OF THE INVENTION  
      The present general inventive concept provides a disk damper having an improved structure to control the flow disturbance of air at a wake region adjacent to the rear end of the disk damper, and a hard disk drive (HDD) having the same.  
      Additional aspects and advantages of the present general inventive concept will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the general inventive concept.  
      The foregoing and other aspects of the present inventive concept may be achieved by providing a disk damper which is spaced, at a predetermined interval, from a disk in a hard disk drive (HDD) and positioned so as to control a head stack assembly (HSA) not to interrupt the movement of the HSA such that vibration of a rotating disk can be controlled, the disk damper comprising a front end positioned to be relatively far from the HSA, a rear end positioned to be relatively close to the HSA, and a first flow channel to induce the air flow caused by a rotation of the disk from the front end to the rear end through the inside.  
      The first flow channel may be formed of a plurality of pipes to bend along a concentric circular arc having a same center as the rotation center of the disk.  
      The plurality of pipes may have a same square or hexagonal section size, respectively.  
      The inside of the disk damper may be filled with a porous material permitting ventilation therethrough, and the first flow channel may be formed through the porous material.  
      The porous material may be woven or non-woven fabric.  
      The disk damper may further include a second flow channel inducing the air flow caused by the rotation of the disk from the front end to a circulating filter positioned outside the circumference of the disk.  
      The foregoing and other aspects of the present inventive concept may also be achieved by providing an HDD which includes at least one disk as a data storing medium, an HSA to move a magnetic head that stores or reads out data to a specific position on a rotating disk, and a disk damper to control the vibration of the rotating disk and spaced, at a predetermined interval, from the disk and positioned so as to avoid the HSA not to interrupt a movement of the HSA, wherein the disk damper includes a front end positioned to be relatively far from the HSA, a rear end positioned to be relatively close to the HSA, and a first flow channel inducing the air flow caused by the rotation of the disk, from the front end to the rear end through the inside of the disk damper.  
      The first flow channel may be formed of a plurality of pipes to bend along a concentric circular arc having a same center as the rotation center of the disk.  
      The plurality of pipes may have a same square or hexagonal section size, respectively.  
      The inside of the disk damper may be filled with a porous material permitting ventilation therethrough, and the first flow channel may be formed through the porous material.  
      The porous material may be woven or non-woven fabric.  
      The HDD may further include a circulating filter to filter foreign materials contained in the air outside the disk, and the disk damper may further include a second flow channel inducing the air flow caused by the rotation of the disk from the front end to the circulating filter.  
      In an embodiment, a plurality of disks are stacked and the disk damper is inserted between two disks adjacent to each other.  
      In an embodiment, one disk is used and the disk damper is positioned above the disk.  
      The foregoing and other aspects of the present inventive concept may also be achieved by providing a hard disk drive comprising a disk damper disposed to control vibration of a disk, and having an front end formed with a front opening to receive air, and a rear end formed with a rear opening to output the air, and an intermediate end formed with one or more apertures and formed between the front end and the rear end to output the air to a portion between the front end and the rear end.  
      The foregoing and other aspects of the present inventive concept may also be achieved by providing a hard disk drive having a disk damper disposed to control an air flow around a disk, and having an front end formed with a front opening to receive air, and a rear end formed with a rear opening to output the air, one or more pipes formed between the front end and the rear end, and one or more apertures formed on at least one of the one or more pipes between the front end and the rear end.  
      The foregoing and other aspects of the present inventive concept may also be achieved by providing a hard disk drive having a disk damper disposed to control an air flow generated from a rotation of a disk, and having a front end formed with a front opening, a rear end formed with a rear opening, one or more front pipe connected with the front end to receive air from the front opening to form one or more front air passages, one or more rear pipes connected with the rear opening of the rear end to form one or more rear air passages, and one or more apertures disposed between the one or more front pipes and the one or more rear pipes to guide the air from the one or more front pipes to an intermediate end between the front end and the rear end. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      These and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:  
       FIG. 1  is a plan view illustrating an example of a conventional HDD (hard disk drive);  
       FIG. 2  is an exploded perspective view illustrating an HDD according to an embodiment of the present general inventive concept;  
       FIG. 3  is a cross-sectional view illustrating a disk damper according to an embodiment of the present general inventive concept;  
       FIG. 4  is a vertical sectional view illustrating the disk damper taken along the line IV-IV of  FIG. 3 ;  
       FIG. 5  is a cross-sectional view illustrating a disk damper according to another embodiment of the present general inventive concept;  
       FIG. 6  is a cross-sectional view illustrating a disk damper according to another embodiment of the present general inventive concept; and  
       FIG. 7  is a vertical-sectional view illustrating the disk damper taken along the line IV-IV of  FIG. 6 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      A Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures.  
      A disk damper and a hard disk drive (HDD) having the same according to various embodiments of the present general inventive concept will now be described more fully with reference to the accompanying drawings.  
       FIG. 2  is an exploded perspective view illustrating an HDD according to an embodiment of the present general inventive concept.  
      With reference to  FIG. 2 , the HDD  100  includes a housing having an inner space formed by coupling a base  101  and a cover  105 . The housing includes first and second disks  110  and  112 , a spindle motor  120 , an HSA (head stack assembly)  130 , a VCM (voice coil motor)  138 , and a disk damper  150 .  
      The housing comprises the base  101  to support the spindle motor  120  and the HSA  130 , and the cover  105  to protect the disks  110  and  112  and coupled to an upper part of the base  101 . The base  101  and the cover  105  are usually made of stainless steel or aluminium materials. However, other materials that provide the intended purposes described herein may be used alternatively.  
      The fist and second disks  110  and  112  are positioned inside the housing. Four or more disks can be positioned in the HDD  100  to increase the data storage capacity. However, as the surface recording density of a disk has been remarkably increased, it is possible to store a sufficient data storage capacity with only one or two disks. Thus, recently the HDD with only one or two disks is usually used.  
      The spindle motor  120  to rotate the first and second disks  110  and  112  is fixedly installed on the base  101 . A ring-shaped spacer  122  to maintain a space between the first and second disks  110  and  112  is inserted between the two disks  110  and  112 . A disk clamp  125  to prevent the disks  110  and  112  from coming loose is coupled at an upper end of the spindle motor  120 .  
      The HSA  130  as a unit to record data on the disks  110  and  112  or read out the data recorded on the disks  110  and  120  is pivotably positioned on the base  101 . The HSA  130  includes a swing arm  132  pivotably coupled around a pivot bearing  137 , first, second, third and forth suspensions  133   a ,  133   b ,  133   c  and  133   d  coupled with the front of the swing arm  132 , and first, second, third and fourth sliders  135   a ,  135   b ,  135   c  and  135   d  supported by the suspensions  133   a ,  133   b ,  133   c  and  133   d , respectively. First, second, third and fourth magnetic heads  136   a ,  136   b ,  136   c  and  136   d  to record and reproduce the data are formed on the sliders  135   a ,  135   b ,  135   c  and  135   d , respectively.  
      The VCM  138  to provide a pivoting force to drive the HSA  130  is controlled by a servo control system and rotates the HSA  130  in a direction according to Fleming&#39;s Left Hand Rule by the interaction between a current input in the VCM coil (not shown) at the rear end of the HSA  130  and a magnet (not shown) of the VCM  138 . Thereby, the four sliders  135   a ,  135   b ,  135   c  and  135   d  attached to the front end of the suspensions  133   a ,  133   b ,  133   c  and  133   d , respectively, move toward the spindle motor  120  or outer circumferences of the first and second disks  110  and  112  from main data surfaces of the disks  110  and  112 .  
      The disk damper  150  to control vibration and noise caused as the disks  110  and  112  rotate in the HDD  100  may be formed of metal, such as aluminium or polymer resin. The disk damper  150  is inserted between the disks  110  and  112  and is spaced, at a predetermined interval, from the disks  110  and  112  so that the disks  110  and  112  do not come into contact with each other. The disk damper  150  is mounted and supported by first, second, and third supporting units  102 ,  103  and  104 , respectively, formed on the base  101 , by screws. The disk damper  150  is positioned to avoid the HSA  130  so as not to interrupt the movement of the HSA  130 , and is designed in an alphabet character “C” shape.  
      A circulating filter  140  to filter foreign materials, such as particles contained in the air flowing inside the HDD  100 , is positioned outside the circumference of the disks  110  and  112 . The circulating filter  140  is supportedly inserted in a filter holder  106  arranged at one side of the cover  105 . An FPC (flexible printed circuit) bracket  143  to connect a FPC  142  connected with the HSA  130  to a main circuit substrate (not shown) positioned under the base  101  is positioned at one side of the base  101  adjacent to the HSA  130 .  
       FIG. 3  is a cross-sectional view illustrating a disk damper according to an exemplary embodiment of the present general inventive concept as illustrated in  FIG. 2 , and  FIG. 4  is a vertical sectional view illustrating the disk damper as taken along the line IV-IV of  FIG. 3 .  
      With reference to  FIGS. 3 and 4 , the disk damper  150  includes a damper body  155  to define an exterior shape of the disk damper  150  with inner and outer side walls  155   a  and  155   b  and upper and lower side walls  155   c  and  155   d , and a plurality of pipes  158  disposed inside the damp body  155 . The damper body  155  allows an air flow to flow into an inside of the damper body  155  and to flow out the damper body  155  through a front end  151  formed with an opening, positioned relatively far from the HSA  130 , and a rear end  152  formed with a second opening, positioned relatively close to the HSA  130 .  
      The plurality of pipes  158  are bent along a concentric circular arc having a same center as a rotation center C of the disks  110  and  112  and induce the air flow caused by the rotation of the disks  110  and  112  from the front end  151  to the rear end  152  through the inside of the disk damper  150 . The plurality of pipes  158  inducing the air flow which flows into the front end  151  of the disk damper  150  and flows out the rear end  152  forms a first flow channel as indicated by arrows (i) illustrated in  FIG. 3 .  
      Since each of the plurality of pipes  158  have the same-sized square sections as illustrated in  FIG. 4 , it is possible to easily and firmly bond other adjacent pipes  158 , and it is also possible to minimize a thickness of the disk damper  150  when the pipes  158  are layered so as to form a plurality of layers. The disk damper  150  according to the embodiment of  FIG. 4  is formed in a manner that the plurality of pipes  158  are horizontally arranged in five columns and layered in three layers. The number of columns and the number of the layers may vary. However, pipes in different shapes, for example, pipes having a hexagonal section, respectively, may be included since the disk damper  150  of  FIG. 4  does not limit the shape of pipes.  
      One or more apertures  160  are formed in the outer side wall  155   b  and the pipes  158  of the disk damper  150  such that the air flow caused by the rotation of the disks  110  and  112  is toward the circulating filter  140 . The plurality of pipes  158  and apertures  160  form a second flow channel inducing the air flow flowing into the front end  151  of the disk damper  150  toward the circulating filter  140 , as indicated by arrows (ii) shown in  FIG. 3 .  
      Accordingly, the pipes  158  forming the first flow channel may be separated from the pipes  158  forming the second flow channel, and may receive the air from the front end  151  and/or the apertures  160  formed between the first and second flow channels. The plurality of pipes  158  may be arranged in a radial direction of the rotation center C, and may include, for example, an inside pipe disposed adjacent to the inside wall  155   a  and away from the outside wall  155   b  in a first circumferential direction of the rotation center C and an outside pipe disposed away from the inside wall  155   a  and adjacent to the outside wall  155   b  in a second circumferential direction of the rotational center C. A first portion of the air flow flowing in the inside pipe may flow from the front end  151  to the rear end  152 , and a second portion of the air flow flowing in the inside pipe may flow from the inside pipe toward the outside pipe and/or an intermediate end formed with opening, such as the apertures  160 , so that the air from the inside pipe and the outside pipe can pass through the filter  40 . The second portion of the air flow flowing from the inside pipe may be combined with at least one portion of the air flow flowing in the outside pipe.  
      A part of the air flow in the counter-clockwise direction caused by the rotation of the disks  110  and  112  flows into the plurality of pipes  158  at the front end  151  of the disk damper  150  and flows out through the rear end  152 , along the first flow channel (i). Therefore, a flow width of the air flow is not rapidly reduced at the front end  151  and is not rapidly increased at the rear end  152 . Consequently, the occurrence of a turbulent flow caused by flow disturbance at the front end  151  and the rear end  152  is controlled, the occurrence of a laminar flow is enhanced, and the vibration of the HSA  130  is reduced by the decrease in the flow disturbance at a wake region T adjacent to the rear end  152 .  
      Further, since a part of the air flow flowing into the front end  151  is induced toward the circulating filter  140  along the second flow channel (ii), a flow rate of the air passing through the circulating filter  140  is increased such that particles-collecting efficiency by the circulating filter  140  can be improved.  
       FIG. 5  is a cross-section view illustrating a disk damper  250  according to another embodiment of the present general inventive concept. The disk damper  250  according to the embodiment of  FIG. 5  can replace the disk damper  150  illustrated in the HDD  100  according to the embodiment of  FIG. 2 .  
      In the same manner as the disk damper  150  according to the embodiment of  FIGS. 3 and 4 , the disk damper  250  according to the embodiment of  FIG. 5  includes a damper body  255  in which inner and outer side walls  255   a  and  255   b  and upper and lower side walls (not shown) define an exterior shape, and a front end  251  and a rear end  252  are open for ventilation, and a plurality of pipes  258  and  259  arranged inside the damper body  255 .  
      The plurality of pipes  158  and  259  are bent along a concentric circular arc having a same center as the rotation center C of the disks  110  and  112  and may include at least one first pipe  258  to induce the air flow caused by the rotation of the disks  110  and  112  from the front end  251  to the rear end  252  through the inside of the disk damper  250 , and at least one second pipe  259  to induce the air flow flowing into the front end  251  toward the circulating filter  140 . The first pipe  258  forms a first flow channel as indicated by the arrows (i) and the second pipe  259  forms a second flow channel as indicated by the arrows (ii). The first pipe  258  and the second pipe  259  can be layered to occupy different layers, respectively. For example, the pipes  258  and  259  can be layered by three layers inside the damper body  255 , wherein the first pipe  258  is layered on the first and third layer and the second pipe  259  is layered on the second layer. One or more apertures  260  are formed in the outer side wall  255   b  of the damper body  255  such that the air flow flowing through the second pipe  259  exits the disk damper  250  and flows toward the circulating filter  140 .  
      A part of the air flow in the counter-clockwise direction caused by the disks  110  and  112  flows into the first pipe  258  at the front end  251  of the disk damper  250  and flows out through the rear end  252 , along the first flow channel (i). Therefore, the flow width of the air flow is not rapidly reduced at the front end  251  and is not rapidly increased at the rear end  252 . Consequently, the occurrence of turbulent flow caused by flow disturbance at the front end  251  and the rear end  252  is controlled, the occurrence of laminar flow is enhanced, and the vibration of the HSA  130  is reduced by the decrease of the flow disturbance at the wake region T adjacent to the rear end  252 .  
      Further, since another part of the air flow flows into the second pipe  259  and is induced toward the circulating filter  140  along the second flow channel (ii), the flow rate of the air passing through the circulating filter  140  is increased such that the particles-collecting efficiency by the circulating filter  140  can be improved.  
       FIG. 6  is a cross-sectional view illustrating a disk damper  350  according to another embodiment of the present general inventive concept, and  FIG. 7  is a vertical sectional view illustrating the disk damper  350  as taken along the line VI-VI of  FIG. 6 . The disk damper  350  according to the embodiment of  FIG. 6  can replace the disk damper  150  illustrated in the HDD  100  according to the embodiment of  FIG. 2 .  
      With reference to  FIGS. 6 and 7 , in the same manner as the disk damper  150  according to the embodiment of  FIGS. 3 and 4 , the disk damper  350  according to the embodiment of  FIG. 6  includes a damper body  355  in which inner and outer side walls  355   a  and  355   b  and upper and lower side walls  355   c  and  355   d  define an exterior shape, and a front end  351  and a rear end  352  are open for ventilation. An inside of the damper body  355  is filled with a porous material  358  permitting ventilation. The porous material  358  may be, for example, a metal net wherein a minute mesh is formed, woven fabric, or non-woven fabric. More specifically, the porous material  358  may be the material having a similar formation structure to the circulating filter  140 . The porous material  358  filled inside the damper body  355  forms the first flow channel to induce the air flow flowing into the front end  351  to the rear end  352  through the inside of the disk damper  350 , as indicated by the arrows (i).  
      one or more apertures  360  are formed at the outer side wall  355   b  of the damper body  355  such that the air flow flowing into the inside of the disk damper  350  through the front end  351  exits the disk damper  350  and flows toward the circulating filter  140 .  
      When a part of the air flow in the counter-clockwise direction caused by the disk  110  and  112  flows into the inside of the disk damper  350  through the front end  351  of the disk damper  350  and passes through the porous material  358 , it is laminarized and flows out through the rear end  352  along the first flow channel (i). Therefore, the flow width of the air flow is not rapidly reduced at the front end  351  and is not rapidly increased at the rear end  352 . Consequently, the occurrence of turbulent flow caused by flow disturbance at the front end  351  and the rear end  352  is controlled, the occurrence of laminar flow is enhanced, and the vibration of the HSA  130  is reduced by the decrease of the flow disturbance at the wake region T adjacent to the rear end  352 .  
      Further, since another part of the air flow flowing into the front end  351  exits the disk damper  350  through the apertures  360  and is induced toward the circulating filter  140 , along the second flow channel (ii), the flow rate of the air passing through the circulating filter  140  is increased such that the particles-collecting efficiency by the circulating filter  140  can be improved.  
      According to the disk damper and the HDD having the same of the various embodiments of the present general inventive concept, the vibration of the HSA is reduced since the flow disturbance of the air in the wake region adjacent to the rear end of the disk damper is controlled. Accordingly, the speed of processing data by the HDD and the reliance thereon are improved, and the characteristics of a PES (position error signal) can be improved.  
      Furthermore, the particles-collecting efficiency by the circulating filter can be improved since the air flow toward the circulating filter is enhanced.  
      Although a few embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.