Abstract:
A storage apparatus has a cabinet stored with an array of memory mediums, a power supply unit housed at the bottom of the cabinet, a fan provided immediately under the top surface of the cabinet and immediately above the memory mediums, and a partition member provided insides the cabinet and configured to partition a first cooling path from mixing with a second cooling path inside the cabinet. The first cooling path of first external air for cooling the memory mediums starts at an inlet on a side surface of the cabinet and ends at the top surface of the cabinet to discharge the first external air out of the cabinet form the top surface. The second cooling path of second external air for cooling the power supply unit ends at the top surface of the cabinet and discharges the second external air out of the cabinet at the top surface.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
   This application relates to and claims priority from Japanese Patent Application No. 2006-223505, filed on Aug. 18, 2006, the entire disclosure of which is incorporated herein by reference. 
   BACKGROUND 
   The present invention generally relates to a high-density mounting storage apparatus housing numerous memory mediums in a cabinet, and in particular relates to a storage apparatus having a configuration for improving the cooling capability in the cabinet. 
   Generally speaking, a portion of the power supplied to a hard disk drive in an electronic apparatus is converted into frictional heat caused by the rotation of the hard disk or resistance heat of an electronic circuit. With a storage apparatus having a plurality of hard disk drives arranged in an array, the denser these hard disk drives are mounted, the higher the heating value. Thus, while the storage apparatus is being operated, it is necessary to cool the hard disk drives and electronic circuits in the storage apparatus. 
   In recent years, as represented by a large storage apparatus configured with a RAID (Redundant Array of Independent Disks) system, for instance, the storage capacity of storage apparatuses is of an increasing trend. In other words, the number of hard disk drives mounted on the storage apparatus is increasing, which means that the mounting density of the hard disk drives is increasing. 
   As a result of this high-density mounting, the power consumption and heating value of storage apparatuses are ever increasing. As a measure against such heat generation, although a fan for introducing external air into the storage apparatus is being enlarged, resistance against the circulation of external air in the storage apparatus is significant due to the high-density mounting of the hard disk drives, and an effect of sufficiently cooling the inside of the storage apparatus has not yet been achieved. Thus, there is no choice but to enlarge the fan even further, which results in distracting noise caused by the fan, and the electricity consumption for operating the fan will also increase. 
   Conventionally, as a magnetic disk device having this kind of cooling system, as described in Japanese Patent Laid-Open Publication No. H8-273345, proposed is a magnetic disk device configured by including in a single apparatus cabinet a plurality of magnetic disk drives for magnetically storing information, a control circuit board mounted with a control circuit for controlling such magnetic disk drives, and a ventilation means for cooling the magnetic disk drives and control circuit board with air cooling, wherein the magnetic disk drives, control circuit board and ventilation means are retained in a frame to configure a single disk box, and a plurality of such disk boxes are housed in a single apparatus cabinet. 
   Further, Japanese Patent Application No. 2006-83445 introduces a storage apparatus comprising a plurality of cooling areas, an external air introduction/exhaust device for guiding external air to the respective cooling areas and subsequently discharging the external air from the exhaust area of the cabinet to the outside of the cabinet, and an external air guidance area for guiding the external air that passed through the respective cooling areas to the exhaust area. The external air guidance area is configured so that the external air that passed through one cooling area will not get mixed with the external air that passed through another cooling area. 
   SUMMARY 
   Nevertheless, although Japanese Patent Laid-Open Publication No. H8-273345 proposes providing a ventilation means to each disk box for cooling each disk unit, no consideration is given to streamlining the exhaust air or miniaturizing the fan. 
   Further, Japanese Patent Application No. 2006-83445 proposes providing a plurality of cooling areas to the storage apparatus, configuring the external air guidance area so that the external air that passed through one cooling area will not get mixed with the external air that passed through another cooling area, and installing the fan for cooling the storage apparatus at the upper part of the storage apparatus so as to reduce the external air to be discharged. It is thereby possible to suppress the noise caused by the fan and the electrical consumption required for the cooling. 
   Nevertheless, the high-density mounting of storage apparatuses has advanced, and the opening space of the cooling path provided between the hard disk boxes mounted on the storage apparatus is becoming narrow. As a result, there is a so-called dead space where the fans installed at the upper part of the cabinet of the storage apparatus cannot face the cooling path, and no consideration was given to the fact that only a portion of the exhaust air volume of the fans could be utilized and the cooling efficiency consequently deteriorated. Further, since a storage apparatus is subject to high-density mounting where apparatuses are mounted on the front and back faces, exhaust air is primarily discharged from the top face of the storage apparatus. The fans installed at the upper face of the storage apparatus for discharging exhaust air generated reflected sound as a result of the noises generated from the fans being reflected off the ceiling since there are no obstacles between the fans and the ceiling. Nevertheless, no consideration was given in inhibiting the reflected sound without interfering with the exhaust air. 
   The present invention was made in view of the foregoing problems. Thus, an object of the present invention is to retain the cooling efficiency of fans even in a high-density mounting storage apparatus, and in particular to inhibit the reflected sound from the ceiling among the noises generated from the fans upon cooling the storage apparatus. 
   In order to achieve the foregoing object, the present invention provides a storage apparatus having a cabinet for storing a plurality of memory mediums in an array, and a power supply unit for supplying power to a drive circuit of the memory mediums. The power supply unit is housed inside the ground plane side of the cabinet, and the plurality of memory mediums are housed inside the cabinet on the power supply unit. This storage apparatus includes a first cooling path to become a passage inside the cabinet of first external air for cooling the plurality of memory mediums, and which ends at an upper end portion of the cabinet, a second cooling path to become a passage inside the cabinet of second external air for cooling the power supply unit, and which ends at the upper end portion of the cabinet, a fan provided to the upper end portion of the cabinet so as to face the memory mediums positioned immediately below from the end of the first cooling path, and for drawing in the first external air to the first cooling path and discharging the first external air that cooled the plurality of memory mediums outside the cabinet, and a partition member for partitioning the first cooling path and the second cooling path so that the first external air and the second external air do not get mixed. The fan is supported by the cabinet so as to be slanted against a peripheral part of the memory mediums positioned immediately below the first cooling path. Also provided is a storage apparatus wherein a duct for covering the fan is provided to the upper end portion of the cabinet, and the duct is configured so as to cushion the operational noise generated from the fan. 
   According to the present invention, it is possible to retain the cooling efficiency of fans even in a high-density mounting storage apparatus, and in particular to inhibit the reflected sound from the ceiling among the noises generated from the fans upon cooling the storage apparatus. 

   
     DESCRIPTION OF DRAWINGS 
       FIG. 1  is a perspective view showing the overall storage apparatus; 
       FIG. 2  is a diagram showing a state where the respective units are housed in a cabinet  200  of the storage apparatus  100 , and the direction of the wind flowing in the respective units; 
       FIG. 3  is a diagram showing the configuration of the storage apparatus; 
       FIG. 4  is a diagram showing a variation of a partition member; 
       FIG. 5  is a diagram showing the configuration of the fans; 
       FIG. 6  is a diagram showing the configuration of the fans; 
       FIG. 7  is a diagram showing the configuration of the fans when installed at a slant; 
       FIG. 8  is a diagram showing the configuration of a duct to be installed at the upper part of the storage apparatus; and 
       FIG. 9  is a diagram showing the configuration of the duct to be installed at the upper part of the storage apparatus. 
   

   DETAILED DESCRIPTION 
   Embodiments of the present invention are now explained with reference to the attached drawings.  FIG. 1  is a perspective view showing the overall storage apparatus. As shown in  FIG. 1 , the storage apparatus  100  is configured by housing, in a cabinet  200  forming a large rectangular shape, a DC power supply  600 , a battery  800 , and an HDD (hard disk) box  300  from the ground plane side of the cabinet toward the top side of the cabinet in that order. The storage apparatus is controlled by a disk controller not shown connected to the storage apparatus. 
   An upper-level system not shown (a host system for example) is connected to the storage apparatus illustrated in  FIG. 1 , and data to be accessed by the host system is stored in the hard disk drives in the HDD box  300 . Each HDD box  300  has a plurality of hard disk drives  300 A arranged in an array. 
     FIG. 2  is a diagram showing a state where the respective units are housed in the cabinet  200  of the storage apparatus  100 , and the direction of the wind flowing in the respective units. Foremost, the foregoing HDD box  300  is housed in the upper row of the storage apparatus  100 . The hard disk drive  300 A in the HDD box  300  is insertably and removably housed in the HDD box  300 . Electric fans  500  are provided at the top face of the storage apparatus  100 . These fans  500  guide the external air from outside the cabinet toward the center of the cabinet via the HDD box  300 , and discharge this external air from the top of the storage apparatus  100 . 
   A total of 128 disk drives  310 A are loaded in an array in the HDD box  300 ; namely, 8 rows in the direction of gravitational force, and 16 rows in a direction perpendicular to the vertical direction. Incidentally, a plurality of frames are assembled to form a rectangular shape so as to configure the overall cabinet  200 . The HDD box  300  is supported by the upper part of the cabinet. Further, the DC power supply  600 , the battery  800  and the AC box  700  are housed in the lower row of the cabinet. 
   The battery  800 , the AC box  700  and the DC power supply  600  are housed inside the lower row of the cabinet  200  as described above, and integrally form the power supply unit  410 A of the storage apparatus. By disposing the heavy power supply unit  410 A in the lower row of the storage apparatus  100 , it is possible to stabilize the storage apparatus  100  upon grounding the storage apparatus  100 . Electric fans  410  are provided at the upper end face of the power supply unit  410 A for drawing in the external air from outside the cabinet  200  into the cabinet. These electric fans  410  guide the external air into the cabinet via the power supply unit  410 A, and discharge such external air outside the cabinet  200 . 
   The DC power supply  600  converts AC power into DC power, and supplies DC power to the disk drive  310 A. The battery  800  supplies backup power to the respective components inside the storage apparatus  100  during a blackout or failure in the DC power supply  600 . The AC box  700  is an intake of AC power to the storage apparatus  100 , and functions as a breaker. AC power introduced into the AC box  700  is supplied to the DC power supply  600 . The heating value generated by the power supply unit  410 A is cooled by the external air supplied into the cabinet with the electric fans  410 . 
   The direction of wind flowing through the respective units is now explained with reference to  FIG. 1  and  FIG. 2 . The cooling area of the storage apparatus  100  is broadly separated into two sections; that is, the cooling area is configured from a path  212  for cooling the HDD box  300 , and a path  214  for cooling the power supply unit  410 A. The electric fans  500  aspirate the external air  216  from the outside to inside of the cabinet via the HDD box  300 . This external air is discharged outside the storage apparatus  100  as exhaust air  218  by the electric fans  500 . The external air  216  passes through the vicinity of the hard disk drives while flowing from the outside to inside of the cabinet so as to cool the hard disk drives. 
   The electric fans  410  explained with reference to  FIG. 2  aspirate the external air  220  from the outside to inside of the cabinet  200  via the power supply unit  410 A, and this external air rises in the cabinet  200 , passes through a cooling path  210 D provided on the side face of a partition member  210  described later to be installed between the HDD boxes  300 , and is discharged outside the cabinet  200  as exhaust air  224  from the side face of the HDD box  300 . The cooling path for the external air being introduced as intake air  216  and thereafter discharged outside the cabinet as exhaust air  218 , and the cooling path for the external air being introduced as intake air  220  and thereafter discharged outside the cabinet as exhaust air  224  are formed so that the external air of the former and external air of the latter do not get mixed. In other words, it is possible to substantially avoid the external air  220  from becoming the external air for cooling the HDD boxes. Incidentally, in  FIG. 1  and  FIG. 2 , the external air is aspirated inside the storage apparatus  100  from the front face and back face of the storage apparatus  100 . 
     FIG. 3  is a perspective view showing this configuration. Although not shown in  FIG. 3 , a pair of HDD boxes  300  is housed inside the storage apparatus  100  respectively from the front side and back side of the storage apparatus  100 . Provided between the pair of HDD boxes  300  is a partition member  210  for substantially differentiating the introduction route of the intake air  220  passing through the cabinet as shown in  FIG. 3  from the introduction route of the external air  216  passing through the cabinet. As a result of this partition member  210 , the introduction route of external air in the cabinet will be as shown in  FIG. 3 . Although this partially overlaps with the explanation of  FIG. 1  and  FIG. 2 , the intake air  216  enters the partition member  210  through the openings  330 A provided to a resistive plate  330  described later from the front face and back face of the HDD box  300 , and is discharged outside the cabinet as exhaust air  218  with the fans  500  at the upper part of the storage apparatus. In  FIG. 3 , the external air  200  aspirated from the periphery of the lower row of the cabinet  200 , without passing through the inside of the HDD box  300 , passes through the external air path  210 D provided to the side face of the partition member  210 , and is discharged outside the storage apparatus  100  as exhaust air  224 . 
   The structure of the partition member  210  is now explained in detail. The partition member  210  is formed in a rectangular shape where the planar surface and inside are opened. The bottom face of the partition member  210  is shielded so that the external air  220  (refer to  FIG. 1 ) will not enter the partition member  210 . An external air path  210 D is provided to the left and right sides of the partition member  210 , which is blocked so that air from inside the partition member  200  will not enter, so as to pass the external air  220  aspirated from the periphery of the lower row of the cabinet  200 . 
   As shown in  FIG. 3 , the partition member  210  is configured by including a bottom face  210 A, left and right side faces  210 C, an external air path  210 D provided to the left and right side faces, and a frame  210 B for forming the overall structure in a rectangular shape. At the front side and back side of the partition member  210 , a resistive plate  330  is fixed to the frame  210 B. This resistive plate  330  is fixed so as to face the HDD box  300  not shown. A plurality of openings  330 A are formed on the resistive plate  330  to allow external air to enter into the partition member  210 . The number of openings is the same for all resistive plates  330 , the opening space is the same, and the position of the openings is also the same. 
   According to this structure, since the external air discharged from the power supply unit  410 A will not get mixed with the external air that passes through the inside of the HDD box  300 , the air that passes through the inside of the HDD box  300  will not be influenced by the external air that is discharged from the power supply unit  410 A. Since the velocity Q of the wind that passes through the openings  330 A can be sought from the product of the air volume and opening area, if all areas of the openings  330 A provided to the resistive plate  330  facing the HDD box  300  are made to be equal, the air volume will be fixed. Thus, the velocity Q will be equal in all openings. The reason the opening area is made equal is to make the air volume and velocity in all openings  330 A constant regardless of the distance from the fans installed at the upper part of the HDD box  300 . Thereby, since external air with constant velocity will consistently pass through the inside of the HDD box  300 , the temperature inside the HDD box  300  can be made uniform, and the reduction of rise in temperature can be sought efficiently. 
   The external air  216  shown in  FIG. 3  is guided into the partition member  210  while retaining constant velocity via the openings  330 A, and the external air  220  rises inside the cabinet through the external air path  210 D provided to the left and right side faces of the partition member  210 , and not inside the partition member  210 . Therefore, the partition member  210  separates the area to which the intake air  216  is guided and the area to which the intake air  220  is guided. The fans  500  merely have to be of a capacity sufficient in aspirating and discharging the intake air  216 , and the fans  410  not shown in  FIG. 3  merely have to be of a capacity sufficient in aspirating and discharging the intake air  220 . 
   In other words, the partition member  210  is formed in a box shape with an open upper part, and is structured to separate the external air by providing the fans at the upper part of the partition member  210  and providing the fans  410  downward at the bottom part of the partition member  210 . Therefore, the noise generated upon operating the fans can be reduced, and external air can be discharged efficiently. Incidentally, since there was no partition member  210  in the past, the intake air  220  and the intake air  216  were mixed inside the cabinet, and the mixed external air was brought together and discharged by the fans  500 . Thus, this led to the enlargement of the fans  500 . As a result, the power consumption and noise of the fans  500  also increased. Further, if the shaft that rotates the blades of the fans is enlarged, it will block the air passage. Thus, if the fans  500  are miniaturized, it will be possible to install the fans according to the channel area, and reduce the hissing sound generated when the fans  500  rotate. 
   As shown in  FIG. 3 , the bottom face  210 A of the partition member  210  has an inclined surface  213 A toward the center of the partition member  210  formed from a front face edge  211 A and a back face edge  211  B of the bottom face, and an inclined surface  213 B not shown at the left and right sides thereof, respectively. Moreover, from the center  215 A of the bottom face  210 A, formed is a ridge line  213 D so as to connect the intersecting point  213 C (not shown) of the inclined surfaces  213 A and  213 B. As a result of the inclined surfaces  213 A,  213 B and the ridge line  213 D, a pair of semi-triangular pyramid-shaped concave portions  217  is formed from the center of the partition member  210  toward the left and right sides thereof. The external air  220  is force fed to the partition member  210  with the fans  410  provided to the upper part of the power supply unit  410 A not shown in  FIG. 3 , hits the bottom face  210 A of the partition member  210 , and is then guided to the left and right side faces of the partition member  210  along the concave portion  217 . The width of the concave portion gradually becomes larger toward the left and right side faces from the center of the partition member  210  since the concave portion is formed in a triangular pyramid shape. As a result, the external air  220  is guided smoothly to the left and right side faces from the center of the partition member  210 . In other words, the external air  220  is guided smoothly to the left and right side faces from the center of the partition member  210  due to the pair of concave portions  217  formed from the center of the partition member  210  toward the left and right side faces thereof. More specifically, the partition member  210  has a concave portion for the exhaust air from the power supply unit  410 A to flow toward a direction in which the HDD box  300  is not installed; that is, toward the side face. Further, the inclined surfaces  213 A,  213 B guide the external air from the front face/back face to the center of the partition member. Moreover, the external air passes through the external air path  210 D provided to the side face of the partition member  210 , and is then discharged from the side face of the HDD box  300 . The flow of external air is shown in  FIG. 3 . 
   Incidentally, the external air path  210 D provided to the side face of the partition member  210  for passing the external air through, as shown in  FIG. 4 , may be formed from a cylindrical shape or other shapes. Further, as shown in  FIG. 4 , the partition member  210  does not have to adopt a configuration of providing a concave portion to the bottom face of the partition member  210 , and may adopt a configuration of using the fans  410  (not shown) provided to the upper part of the power supply unit  410 A to introduce the external air into the external air path  210 D provided to the side face of the partition member  210 . 
   The configuration of the fans  500  installed at the upper part of the partition member  210  is now explained with reference to  FIG. 5  and  FIG. 6 . A plurality of round fans  500  installed at the upper part of the partition member  210  are aligned and installed so as to face the cooling path, which is space inside the partition member  210 , at the upper part of the partition member  210  installed between the HDD boxes  300 . Thereupon, as shown in  FIG. 6 , the fans  500  are supported by the cabinet  200  so as to be inclined against the peripheral part of the HDD boxes  300  positioned immediately below the end of the cooling path that passes through the HDD boxes  300 . 
   The reason why the fans  500  can be installed at a slant inside the storage apparatus is because a one-inch corner pipe  301  for supporting the cabinet is installed between the fans provided at the upper part of the cabinet and the ceiling board at the upper end of the storage apparatus. Thereby, the space formed by the thickness of the corner pipe  301  will exist between the fans  500  and the ceiling board  303  of the cabinet, and it will be possible to use such space. As shown in  FIG. 7 , when giving consideration to the thickness of the corner pipe  301 , the maximum angle of inclination between the upper end face of the HDD boxes  300  and the installation face of the fans  500  will be 6 degrees. 
   Conventionally, as shown in  FIG. 5 , the fans  500  were aligned and installed horizontally at the upper part of the partition member  210 . Nevertheless, if the fans are installed as illustrated in  FIG. 5 , a so-called dead space, which is an area that does not face the cooling path among the fans  500 , will arise, and it was not possible to utilize such dead space that is not facing the cooling path. As shown in  FIG. 6 , by installing the fans  500  at a slant against the upper end face of the memory medium housing unit, it is possible to secure space below the fans  500 , and all faces of the fans  500  will face the cooling path. Thus, it will be possible to discharge the exhaust air while utilizing all faces of the fans  500 , and the cooling efficiency will improve thereby. Further, since the resistance of wind will also decrease, the hissing sound of the fans  500  will decrease, and the noise will also decrease. Moreover, even if the fans  500  are installed at a slant, as described above, since the fans  500  will be housed in a space formed between the fans  500  and the ceiling board that is secured with the corner pipe  301 , it is not necessary to change the dimension of the storage apparatus  100 . 
   A duct  900  installed at the upper end of the storage apparatus  100  is now explained with reference to  FIG. 8  and  FIG. 9 . The duct  900  is formed by combining a plurality of members  901  equipped with a cushioning material, and is installed at the upper end portion of the cabinet so as to cover the fans  500 . In other words, the exhaust air from the fans  500  installed at the upper end of the storage apparatus  100  is blown against the member  901  equipped with the cushioning material, and the exhaust air is reflected to change the direction thereof so that it is discharged to a direction other than the ceiling. Specifically, for instance, as shown in  FIG. 8  and  FIG. 9 , the member  901  equipped with the cushioning material is installed at the upper end of the storage apparatus  100  so as to surround the four sides; namely, the front face, back face and side faces at the upper end of the storage apparatus  100 . In addition, a first member  901  equipped with a cushioning material is further provided to the member  901  equipped with the cushioning material so that the exhaust air from the fan  500  will be discharged thereto. A second member  901  equipped with a cushioning material is further provided so that the exhaust air blown against the member  901  equipped with the cushioning material will be discharged outside the storage apparatus  100 . Moreover, the exhaust air is blown against the second member  901  equipped with the cushioning material so as to be discharged outside the storage apparatus  100 . The exhaust air may be reflected and discharged into one or more directions. 
   All inner faces of the duct  900  are configured from the members  901  equipped with a cushioning material  903 . The exhaust air from the fans  500  installed at the upper end of the cabinet  200  is blown against and reflected off the first and second members  901  equipped with the cushioning material, and discharged outside the storage apparatus  100  while reducing the noise. Thereupon, the exhaust air is made to hit the first member and second member  901  equipped with the cushioning material mounted inside the duct  900  at least once so as to reduce the noise. 
   For example, when using a member equipped with urethane foam as the cushioning material for reducing noise, it will be possible to absorb sound sources having a high frequency of 1000 Hz to 2000 Hz, and obtain a sound-absorbing effect of absorbing high-frequency sounds such as the hissing sound of fans. It is also possible to use a sound-absorbing material that is more expensive than the cushioning material as a replacement of such cushioning material. In such a case, the sound-absorbing material will be able to absorb low-frequency sounds in the range of 800 Hz to 900 Hz, which is the frequency of fan sounds. In addition, it is also possible to broaden the sound-absorbing area and mount a concavo-convex cushioning material capable of improving the sound absorbing efficiency in order to absorb sound sources of broader frequencies. 
   As a result of installing the duct  900  at the upper end of the cabinet  200 , the reflected sound to the ceiling will decrease. Thus, noise generated from the storage apparatus can be reduced on the whole. Further, since the duct  900  having the foregoing configuration can freely change the direction of the exhaust air or the reflected direction of the exhaust air, it is possible to meet the customer needs and effectively reduce noise in the direction or location where customers wish to reduce such noise. Moreover, since the duct  900  can be removably installed at the upper part of the cabinet of the storage apparatus  100 , it is possible to freely remove or reinstall such duct  900  when there is any change in the customer needs. 
   The embodiments of the present invention were described above to facilitate the understanding of the present invention, and are not intended to limit the interpretation of the present invention in any way. The present invention may be modified or improved without deviating from the gist thereof, and equivalents of the present invention are also included therein.