Vibration damping unit
A vibration damping unit includes a rack-mounted support body removably mounted on a rack. A mass is supported on the support body for movement along an imaginary plane. An elastic member is coupled to the support body and the mass. The support body is removable from the rack. The vibration damping unit can be mounted on an existing rack in a facilitated manner without any change in the design of the rack. Workers can be released from troublesome works, such as moving the rack, even when the vibration damping unit is applied to the rack. The means for preventing sway or vibration can be applied to the rack even when an electronic apparatus, including a disk array apparatus and the like, is in operation inside the rack.
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1. Field of the Invention
The present invention relates to a method of preventing the sway of a rack accommodating a rack-mounted disk array apparatus, for example.
2. Description of the Prior Art
A rack-mounted disk array apparatus is well known. The disk array apparatus is mounted on a rack located on a seismic isolation apparatus. The seismic isolation apparatus serves to reduce the sway of the rack. The disk array apparatus is thus allowed to keep its normal operation without any interruption. Lifting up the rack is required to place the rack on the seismic isolation apparatus.
The rack weighs at least 150 kg. The disk array apparatus or apparatuses mounted in the rack serves to further increase the weight. It is quite difficult to lift up the rack onto the seismic isolation apparatus. What is worse, lifting up the rack should interrupt the operation of the disk array apparatus. In other words, once the disk array apparatus starts operating, the rack cannot normally enjoy the seismic isolation.
SUMMARY OF THE INVENTIONIt is accordingly an object of the present invention to provide a vibration damping unit contributing to prevention of the sway of an existing rack in a facilitated manner.
According to the present invention, there is provided a vibration damping unit comprising: a rack-mounted support body removably mounted on a rack; a mass or weight supported on the support body for movement along an imaginary plane; and an elastic member coupled to the support body and the mass.
The support body of the vibration damping unit is removable from the rack. The vibration damping unit can be mounted on an existing rack in a facilitated manner without any change in the design of the rack. Workers can be released from troublesome works, such as moving the rack, even when the vibration damping unit is applied to the rack. The means for preventing sway or vibration can be applied to the rack even when an electronic apparatus, including a disk array apparatus and the like, is in operation inside the rack.
The mass is supported on the support body for movement along an imaginary plane. The elastic member is interposed between the support body and the mass. The elastic member serves to realize the reciprocation of the mass along the imaginary plane. The reciprocation of the mass contributes to a significant suppression of the sway or vibration of the rack when the rack suffers from an earthquake, for example. The rack is allowed to have a smaller rigidity. The assembling process can be simplified. The simplified process leads to a reduction in the production cost of the rack. A reduction in the rigidity greatly contributes to a significant reduction in the weight of the rack.
The mass may comprise: a tray coupled to the support body for movement along the imaginary plane; and at least one weight member removably mounted on the tray. The amount of mass can be adjusted depending on the number of the weight member. This structure enables adjustment of the amount of the mass in accordance with the resonance frequency of the rack, for example.
BRIEF DESCRIPTION OF THE DRAWINGSThe above and other objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiment in conjunction with the accompanying drawings, wherein:
As conventionally known, recording disk drives or hard disk drives (HDDs) are mounted in the individual disk array apparatus 11. The hard disk drive may include a recording disk or hard disk (HD) having the rotation axis extending in the vertical direction perpendicular to the floor, for example. In this case, each disk array apparatus 11 holds fifteen hard disk drives. Alternatively, the rotation axis of the hard disk may extend in the horizontal direction in parallel with the floor.
A vibration damping unit 14 is mounted on the rack 12 just below the top plate of the rack 12. The vibration damping unit 14 is capable of sliding on the rack 12 along a horizontal plane. The vibration damping unit 14 can thus be withdrawn from the front side of the rack 12. The vibration damping unit 14 is coupled to the rack 12 when the vibration damping unit 14 is placed inside the rack 12. Screws 15 may be utilized to couple the vibration damping unit 14, for example. The screws 15 may be screwed into support columns of the rack 12, for example.
As shown in
A pair of first rails 22, 22 is located within the inner space of the support body 21. The first rails 22, 22 are designed to extend in a first direction FD. The first direction FD is set along a horizontal plane in the right and left direction of the vibration damping unit 14. The first rails 22, 22 extend in parallel with each other. The first rails 22 may be fixed to the bottom plate 21a of the support body 21. Screws may be utilized to fix the first rails 22, for example.
Sliders 23 are mounted on the first rails 22, respectively. The sliders 23 are capable of sliding along the first rails 22 in the first direction FD. A second rail 24 is coupled to the sliders 23, 23. The second rail 24 may be fixed to the sliders 23. The second rail 24 is designed to extend in a second direction SD perpendicular to the first direction FD. The second direction SD is set along the horizontal plane in the back and front direction of the vibration damping unit 14. The second rail 24 serves to connect the sliders 23, 23 to each other.
A tray 25 is mounted on the second rail 24. The tray 25 is capable of sliding along the second rail 24 in the second direction SD. At least one weight member 26 is mounted on the tray 25, for example. The weight members 26 are thus coupled to the support body 21 for movement along an imaginary plane defined on the surface of the bottom plate 21a, for example. The weight members 26 may removably be attached to the tray 25. Screws may be utilized for attachment, for example. Each weight member 26 may weigh 1 kg, for example. The tray 25 and the weight members 26 in combination serve as a mass according to the present invention.
First coil springs 27 and first dampers 28 are incorporated within the inner space of the support body 21. The first coil spring 27 and the first damper 28 are designed to extend in parallel with the corresponding first rail 22. Pairs of tabs 29, 29 are formed on the bottom plate 21a so as to stand from the bottom plate 21a. The tabs 29, 29 of each pair are spaced from each other in the first direction FD. The first coil spring 27 and the first damper 28 are located in a space between the pair of tabs 29, 29.
The slider 23 is located in a space between the first coil spring 27 and the first damper 28. The first coil spring 27 is coupled to the slider 23 at one end and to the tab 29 at the other end. The elasticity of the first coil spring 27 serves to drive the slider 23 for reciprocation along the first rail 22 in a set period. The first damper 28 is likewise coupled to the slider 23 at one end and to the tab 29 at the other end. The first damper 28 serves to attenuate the movement of the slider 23.
Likewise, a pair of second coil springs 31, 31 is incorporated within the inner space of the support body 21. The second coil springs 31, 31 are designed to extend in parallel with the second rail 24. The second coil springs 31, 31 are located in series in a space between the sliders 23, 23. A pair of second dampers 32, 32 is incorporated within the inner space of the support body 21. The second dampers 32, 32 are designed to extend in parallel with the second rail 24. The second dampers 32, 32 are located in series in a space between the sliders 23.
The tray 25 is located between the second coil springs 31, 31 as well as between the second dampers 32, 32. Each of the second coil springs 31 is coupled to the slider 23 at one end and to the tray 25 at the other end. The elasticity of the second coil springs 31 serves to drive the tray 25 for reciprocation along the second rail 24 in a set period. Each of the second dampers 32 is likewise coupled to the slider 23 at one end and to the tray 25 at the other end. The second damper 32 serves to attenuate the movement of the tray 25.
As shown in
As shown in
Now, assume that the rack 12 suffers from a sway in the second direction SD because of an earthquake, for example. As shown in
The vibration damping unit 14 is removably mounted on the rack 12 in the same manner as the disk array apparatus 11. The existing rack 12 thus easily receives the vibration damping unit 14 without any change in design. One is released from troublesome works, such as moving the rack 12, even when the vibration damping unit 14 is applied to the rack 12. Moreover, the means for preventing sway or vibration can be applied to the rack 12 even after the disk array apparatus 11 is in operation.
Since the vibration damping unit 14 serves to sufficiently suppress sway or vibration of the rack 12, the rack 12 is allowed to have a smaller rigidity. Welding can be replaced with riveting in the production process of the rack 12. The production process can be simplified. The simplified process leads to a reduction in the production cost of the rack 12. A reduction in the rigidity greatly contributes to a reduction in the weight of the rack 12.
The first and second coil springs 27, 31, the first and second dampers 28, 32 and the weight members 26 can be removed in a facilitated manner. The spring constants of the first and second coil springs 27, 31 can thus be adjusted depending on the resonance frequency of the rack 12 and the vibration damping unit 14. The damper constants of the first and second dampers 28, 32 can likewise be adjusted. The amount of the mass can also be adjusted.
The inventors have observed the effect of the vibration damping unit 14 based on a computer software analysis. As shown in
Here, the height of the individual support columns 43 in the z-axis was set at 1,800 [mm]. The length of the upper and lower frames 44 in the x-axis was set at 600 [mm]. The length of the upper and lower frames 44 in the y-axis was set at 950 [mm]. The bottom surface of the lower frame 44 was located at a height of 50 [mm] from the bottom ends of the support columns 43. The movement of the bottom ends of the support columns 43 was restrained. The weight of the rack 42 was set at 150 kg. The Young's modulus of the rack 42 was set at 193.198 [GPa]. The Poisson's ratio of the rack 42 was set at 0.3.
As is apparent from
First to ninth specific examples were prepared for the observation. As shown in
As shown in
As shown in
Referring also to
The inventors have also observed the influence of the position of the vibration damping unit 14 in the rack 12. A computer software analysis was used for the observation in the same manner as described above. As shown in
The same values were used for the Young's modulus, the Poisson's ratio and the weight of the rack 42. The same value was also used for the weight of the mass 47. The spring constants of the coil spring 45 in the vibration damping unit 14 were set at 493 [N/mm]. The damper constants of the dampers 46 in the vibration damping unit 14 were set at 300 [Nmm/s]. The movement of the bottom ends of the support columns 43 was restrained. The vibration damping unit 14 was thus allowed to move only along the xy plane.
Specific examples A to C were prepared for the observation. The specific example A had the vibration damping unit 14 imaginarily incorporated within the upper frame 44. The specific example B had the vibration damping unit 14 imaginarily incorporated within the first middle frame 44a. The specific example C had the vibration damping unit 14 imaginarily incorporated within the second middle frame 44b. The same comparative example as described above was prepared. The vibration damping unit 14 was omitted in the comparative example.
The rack 42 was subjected to a sway in the x-axis at the acceleration of 1 [G] or 9.8 m/s2 in the specific example A to C as well as the comparative example. The decrement of the sway was set at 1%. A response acceleration was measured at a measuring point 48 set at one of the corners of the upper frame 44. The maximum or peak of the response acceleration was observed in the specific example A to C as well as the comparative example, respectively.
As shown in
As is apparent from the ratio to the specific example A, it has been confirmed that the specific example A exhibits the minimum value of the response acceleration. In other words, it has been confirmed that the maximum response acceleration reduces as the vibration damping unit 14 gets closer to the top of the rack 12. It has thus been revealed that the vibration damping unit 14 is preferably located as close to the top as possible in the rack 12.
The vibration damping unit 14 can be applied to a rack containing two or more server computers 13, other types of electronic apparatus and other types of recording medium drive as well.
Claims
1. A vibration damping unit comprising:
- a rack-mounted support body removably mounted on a rack;
- a mass supported on the support body for movement along an imaginary plane; and
- an elastic member coupled to the support body and the mass.
2. The vibration damping unit according to claim 1, wherein the mass comprises:
- a tray coupled to the support body for movement along the imaginary plane; and
- at least one weight member removably mounted on the tray.
Type: Application
Filed: Feb 21, 2006
Publication Date: May 31, 2007
Applicant: FUJITSU LIMITED (Kawasaki)
Inventors: Hiroshi Hidaka (Kawasaki), Yasushi Uraki (Kawasaki)
Application Number: 11/357,122
International Classification: A47F 7/00 (20060101);