Bracket for disk drive

[0001] This application claims the benefit of Korean Application Nos. 10-2005-0064726, filed Jul. 18, 2005, and 10-2005-0083696, filed Sep. 8, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

[0002] 1. Field of the Invention

[0003] The present invention relates to a disk drive, and more particularly, to a bracket for a disk drive which can protect a disk drive from impact by its buffering ability and prevent mutual interference between circuits positioned below the bracket.

[0004] 2. Description of the Related Art

[0005] A Hard Disk Drive (hereinafter, HDD) mounted on a bracket generally includes a spindle motor to rotate a disk and an actuator having a head for recording data to the disk and reading the data recorded on the disk. An internal vibration occurs due to the spindle motor or the actuator embedded in the HDD. A vibration blocking mount is used for solving this problem, thereby minimizing the rotation vibration factor caused by inner spindle force, as disclosed in U.S. Pat. No. 5,400,196. However, vibration introduced from an external source may be not prevented. A matter of greater concern than internal vibration is a vibration caused by an external impact. As HDDs become miniaturized and lightened and attached to a portable device, vibration caused by an external impact becomes a more serious matter.

[0006] An external impact causes damage to a HDD, such as the dislocation of the rotation center of a disk, damage to a magnetic disk, interference to the normal operation of a spindle motor, interference in reading recorded information and magnetic or physical destruction of the recorded information. Currently, an ultra slim HDD is determined to be the optimal storage medium since it is cheaper than a general flash memory device with comparable capacity and the power consumption is less than 1 W which makes it possible to be installed in a portable device. Accordingly, an ultra slim HDD was developed where the thickness was reduced to less than 1 inch, such that the ultra slim HDD was installed in a portable device. A product whose thickness is 1 inch is being used in an MP3 (MPEG Audio Layer-3) player or PMP (Portable Multimedia Player), and a product whose thickness is less than 1 inch may be applicable to not only a cellular phone, but also a wireless AP (Access Point), a PDA (Personal Digital Assistant), or a navigational system. Thus, the ultra slim HDD is expected to extend its share of the market.

[0007] As described above, the application range of an ultra slim HDD is becoming extensive, but research on a method of protecting the HDD from vibration occurring due to an external impact is unsatisfactory.

[0008] FIG. 1 is an exploded perspective view illustrating a buffer member attached on a conventional HDD. This invention is disclosed in U.S. Patent Appl. Pub. No. 2003/35281A1. As illustrated in the figure, the invention discloses that an HDD 2 is mounted on a bracket 12 and a plurality of buffer members 131, 132, 133, and 134 are provided below the bracket 12, which makes it possible to absorb impact. In FIG. 1, drawing symbol 3 is a buffer module, 311 is an upper case, and 312 is a lower case, which are not described herein.

[0009] However, in the case of separately providing buffer members, the installation space of an ultra slim HDD installed in a portable device is insufficient. Also, the entire size of a module becomes larger due to the size of the buffer members. Also, in the case of using a member whose maximum compressed ratio is about 30%, such as rubber, as a buffer member, its buffering ability may be less than 50%. Also, in the case the displacement of an HDD caused by an external impact is large, a second impact may occur.

[0010] Also, in the case of an HDD installed in a portable device, an external impact acceleration is generally more than 5000G. In the case of an HDD installed in a portable device, vibration and impacts occur more frequently and with greater intensity than when installed in a personal computer. With a portable device, there is the problem of not installing an effective amount of buffer members or the vibration blocking mount can not be properly installed due to the limitation for the size and weight of the HDD.

[0011] Also, there is needed a buffer which is applicable to not only the HDD but also a disk drive including a motor such as an optical disk drive, and capable of effectively buffering an external impact and an internal vibration.

[0012] Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

[0013] To solve the problems described above, the present invention provides a bracket that can effectively protect a disk drive such as an HDD from an external impact, without installing a buffer member or vibration blocking mount.

[0014] The present invention also provides a bracket which has a buffering ability and whose size and weight are small enough to be installed in a disk drive without increasing the size and the weight since no additional buffering device is installed.

[0015] The present invention also provides a bracket that embodies low rigidity and has an improved buffering function by reducing the natural frequency of the bracket.

[0016] The present invention also provides a bracket that has an excellent buffering ability and can prevent the interference between circuits positioned on the bracket.

[0017] The present invention also provides a bracket that can effectively protect a disk drive from a second impact and the second impact occurs when the displacement of the disk drive is large due to a huge external impact.

[0018] To achieve the objectives as described above, according to an aspect of the present invention, there is provided a bracket for a disk drive, including: a base plate containing the disk drive; a side wall portion vertically protruded from an end portion of the base plate; and a displacement portion extended from the side wall portion and bending due to a vibration transmitted by making contact with the disk drive.

[0019] The side wall portion may be protruded from a corner of the base plate in the shape of an “L” or may be protruded from an end portion of the sideface of the base plate to be parallel therewith in the shape of an “I”.

[0020] The displacement portion may be inwardly bent to be in contact with the disk drive in the shape of an “S” or may be spaced apart at a certain interval from the base plate, extended from both ends of the side of the side wall portion and in contact with the sideface of the disk drive. Also, the displacement portion includes: an extension portion extended from the side wall portion in the direction of the side surface of the hard disk; a bent portion inwardly bent from the extension portion; and a contact portion extended from the bent portion to be in surface contact with the sideface of the disk drive.

[0021] The bracket may be formed of plastic resin and manufactured by injection molding.

[0022] According to another aspect of the present invention, there is provided a bracket for a disk drive, where the bracket contains the disk drive on its one surface, and includes: side wall portions vertically protruded from the one surface; a displacement portion extended from the side wall portion in the direction of the one surface, spaced apart from the one surface and bending due to a vibration transmitted by making contact with the disk drive; and a partition wall protruded from the surface opposite to the one surface, isolating circuits provided below the opposite surface and preventing mutual interference caused by electromagnetic waves.

[0023] The side wall portion may be protruded from the sideface of the bracket in the vertical direction of the one surface and in the shape of an “I”, and the displacement portions may be extended from both sides of the side wall portion and inwardly bent to be in surface contact with the sideface of the disk drive. Or, the side wall portion may be protruded from the corner of the one surface and in the shape of an “L”, and the displacement portions may be extended from both sides of the side wall portion and inwardly bent to be in contact with the sideface of the disk drive.

[0024] According to yet another aspect of the present invention, there is provided a bracket for a disk drive, where the bracket contains the disk drive and includes partition walls protruded from the surface opposite to the surface where the disk drive is mounted, and the partition walls isolate circuits provided below the bracket and prevent the mutual interference caused by electromagnetic waves.

[0025] A metal coating is formed on the surface of the bracket where the partition walls are formed.

[0041] Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below to explain the present invention by referring to the figures.

[0042] FIG. 2 is a perspective view illustrating a bracket for a disk drive according to a first embodiment of the present invention, and FIG. 3 is an enlarged perspective view illustrating part “III” in FIG. 2.

[0043] As illustrated in the figures, a disk drive 10 of the present invention includes a base plate 100, side wall portions 200, and displacement portions 300.

[0044] The base plate 100 is formed in the identical shape to the disk drive 10 and the size of the base plate 100 is formed to be slightly larger than the disk drive 10. For example, if the disk drive 10 is a right hexahedron, the base plate 100 has an installation space whose section is a square in order to match with the square corner of the disk drive 10, and the size of the base plate 100 is formed to be a little larger to contain the displacement due to vibration with the displacement portions 300. The displacement portion 300 will be described later. In the case of the shape of the disk drive 10 being different, the base plate 100 may be different in correspondence thereto.

[0045] A combining portion 400 is extended from each corner of the base plate 100 and connected to a portable device. The combining portion 400 includes a hole 410, according to the present invention, so that the combining portion 400 may be forcibly attached to each corner by using a bolt 420, but is not limited to the bolt 420. The combining portion 400 may be forcibly attached to each corner by various methods, such as welding, a rivet, tape or adhesives.

[0046] The base plate 100 may be manufactured by using a plastic resin. Also, The base plate 100 may be manufactured via injection molding using a plastic resin. Namely, since the base plate 100 including the side wall portions 200 and the displacement portions 300 may be molded at the same time by injection, the productivity may be improved.

[0047] The side wall portions 200 are vertically extended from four corners of the base plate 100 and the width and height of each side wall portion 200 is uniform. Namely, the side wall portion 200 is protruded from each corner of the base plate 100, in the shape of an “L”. The base plate 100 is formed larger than the disk drive 10. Thus, when the disk drive 10 is contained in the base plate 100, the side wall portions 200 vertically extended from the corners of the base plate 100 do not make contact with the disk drive 10.

[0048] A position of the side wall portion 200 is not limited to the corner of the base plate 100. The side wall portion 200 may be formed on any position of an end portion of the base plate 100, if said any position is not in contact with a disk drive and is not interfering with the mounting of the disk drive. Detailed description related thereto will be described in embodiment 2.

[0049] Only one side of the displacement portion 300 is connected to the side wall portion 200, and constructed to be capable of bending or rotating to a certain extent. Also, the displacement portion 300 is inwardly bent in the shape of an “S”.

[0050] The above will be further described in detail with reference to FIGS. 4 and 5. FIG. 4 is a side view illustrating the bracket for the disk drive according to the first embodiment of the present invention, and FIG. 5 is a top view illustrating the bracket for the disk drive according to the first embodiment of the present invention.

[0051] As illustrated in the figures, the displacement portion 300 includes an extension portion 311, a bent portion 312 and a contact portion 313. The extension portion 311 is extended from the side wall 200 to be in parallel therewith. The bent portion 312 is inwardly bent from the extension portion 311. The contact portion 313 is extended from the bent portion 312 to be in contact with the sideface of a disk drive.

[0052] The displacement portion 300 is horizontally extended from the base plate 100 to be in contact with a side wall of the disk drive 10. Also, the displacement portion 300 is spaced apart from the base plate 100 at a predetermined interval d1. The interval d1 serves to allow freedom so that the displacement portion 300 can bend according to a vibration of the disk drive 10. The smaller the size of the interval d1, the better, but should be within a range which does not interfere with the displacement of the displacement portion 300.

[0053] The thickness d2 of the displacement portion 300 may be less than 0.4 mm. The interval d3 between the disk drive 10 and the side wall portion 200 is a space where the displacement portion 300 can bend to the maximum, which is less than 1 mm. If the displacement portion 300 bends beyond the range of d3, the displacement portion 300 may have an impact with an external device. However, if designed as described above, a disk drive can be protected from an external impact, which occurs when the displacement is beyond the range of about 0.6 mm.

[0054] Hereinafter, the effects of the present invention will be described as follows.

[0055] The displacement portion acts as a plate spring and helps a bracket to embody a low rigidity. Also, a low rigidity functions to reduce the natural frequency and improve a vibration characteristic.

[0056] To describe in detail by referring to FIG. 6, it may be modeled that the disk drive 10 is a mass having the mass m and the bracket 20 is a spring having a rigidity coefficient k and damping coefficient c. In the case the bracket 20 and the disk drive 10 are modeled as a second system, the equation of motion of the system with respect to an external input F is as
m·d²(x)/dt²+c·d(x)/dt+k·x=F  [Equation 1]
In this case, W_n is the natural frequency of the system as
Wn=√{square root over (k/m)}  [Equation 2]

[0057] As shown in Equation 2, the rigidity is in proportion to the natural frequency. Namely, in the case where the rigidity is reduced, the natural frequency is reduced, thereby improving the vibration characteristic.

[0058] In the system, in the case where an external input whose size is A_in and frequency w_d is inputted, the external input F is shown in Equation 3 and frequency ratio and transmittance are as Equations 4 and 5, respectively,
F=A_in sin w_dt  [Equation 3]
frequency ratio=wd/wn  [Equation 4]
transmittance=A_out/A_in  [Equation 5]

[0059] In this case, A_out is the maximum amplitude of movement of the disk drive 2. The relation between the rigidity, or the natural frequency, and vibration characteristic is illustrated in detail in FIG. 7. In FIG. 7, the x axis indicates the frequency ratio and the y axis indicates the transmittance in a log scale. As illustrated, in the case of Equation 3 where a damping coefficient is low, transmittance most severely spikes in the case of an external input identical with the natural frequency, namely, where the x axis is 1, and enters a buffer zone 6 where the frequency ratio is √{square root over (2)}. In the case of 4 where a damping coefficient is high, transmittance shows a similar shape. In this case, the buffer area 6 indicates an area where the transmittance is less than 1, in which the amount of the external impact A_in becomes less than the transmitted amount A_out.

[0060] Namely, in the case where the frequency ratio is more than √{square root over (2)} regardless of the decrement value, it enters the buffer area 6 and greater buffer effect may be expected because the frequency ratio is in inverse proportion to the natural frequency. Also, since the natural frequency is in proportion to the rigidity, it is previously considered to lower the rigidity in designing a bracket.

[0061] To prove the effects of the present invention, simulation results are shown in FIG. 8. FIG. 8 is a graph illustrating the size of impact acceleration with respect to time.

[0062] As illustrated in the figure, in the case an external input A in the shape of half sine is inputted to about 5000G, which is 5000 times of the acceleration of gravity, for about 0.3 msec, the maximum size of acceleration B transmitted to a disk drive is 1744 G and transmission is 34.8%. Thus, there is more or less 65% buffering effect. In this case, the mass m of the disk drive is 12.5 g, the rigidity coefficient k is 54.8 kN/m, the damping coefficient is 0.1, and the natural frequency W_n of the system is 333.3 Hz.

[0063] Accordingly, since a bracket has an improved buffering function by embodying a low rigidity and reducing the natural frequency of the bracket, the bracket can effectively protect a disk drive from an external impact, without installing a buffer member or vibration blocking mount. Also, since an additional device is not needed, the bracket has a small installation space and is lightweight. If a buffer member and a bracket according to the present invention are used together because there is sufficient installation space, buffering effects may be greater and more effective.

[0064] FIG. 9 is a perspective view illustrating a bracket for a disk drive according to a modified example of the first embodiment of the present invention.

[0065] As illustrated, a side wall portion 220 is protruded from the side face of the bracket in the vertical direction of the one surface and in the shape of an “I”. Displacement portions 320 are extended from both sides of the side wall portion 220 and inwardly bent to be in contact with the side surface of the disk drive.

[0066] The displacement portion 320 includes an extension portion 321, a bent portion 322 and a contact portion 323. The extension portion 321 is extended from the side wall portion 220 to be in parallel therewith. The bent portion 322 is inwardly bent from the extension portion 321. The contact portion 323 is extended from the bent portion 322 to be in contact with the side of the disk drive.

[0067] FIG. 10 is a perspective view illustrating the bottom of a bracket for a disk drive according to a second embodiment of the present invention, and FIG. 11 is a sectional view illustrating how the bracket for the disk drive according to the second embodiment of the present invention is mounted in a portable device.

[0068] As illustrated in the figures, a disk drive 10 is mounted in an electronic device such as a portable device. In the present embodiment, a portable device was used as an example of an electronic device, but the present invention is not limited thereto.

[0069] Also, a partition wall 150 is protruded from a position opposite to the base plate 100 containing the disk drive 10 and isolates circuits 510 and prevents interference between the circuits 510. The circuits 510 are provided on a printed circuit board 500 (hereinafter, PCB). The disk drive 10, bracket and PCB 500 are fixed in a housing 600 of a portable device.

[0070] When the circuits 510 are driven, electromagnetic waves generate around the circuits 510 and cause the malfunction of other circuit members. However, since the partition walls 150 isolate the circuits 510, the interference as above can be prevented. Also, in the case where a metal coating is formed on the opposite surface of the base plate 100, the interference between the circuits can be further prevented. It is more effective to form the partition walls 150 between circuits generating more electromagnetic waves and isolate the circuits. Circuits generating more electromagnetic waves generally function at a high-frequency.

[0071] Namely, the surface of the base plate 100 where the disk drive 10 is mounted is used to fix the disk drive 10 by using the displacement portions 300. Also, the partition walls 150 are formed on the surface of the base plate 100 where the disk drive 10 is not mounted, and prevent interference between the circuits 510 provided on the PCB 500. In other words, the present invention includes partition walls protruded from the surface opposite to the surface where the disk drive is mounted. The configuration as above can not only effectively protect a disk drive from an external impact but also prevent the interference between circuits positioned on a bracket.

[0072] FIG. 12 is a perspective view illustrating a bracket for a disk drive according to a third embodiment of the present invention, and FIG. 13 is a partial sectional view illustrating the combined bracket and disk drive according to the third embodiment.

[0073] As illustrated in the figures, a combination protrusion 700 is vertically protruded from a base plate 100 of a bracket and inserted into a hole 710 of a disk drive 10. The holes 710 are formed on each corner of the disk drive 10. The inside of the hole 710 may be formed of a cylinder or a cone or a truncated cone whose diameter gets narrower as it goes up to be forcibly combined with the combination protrusion 700.

[0074] The combination protrusion 700 includes a projection portion 701 and a contact portion 702. The projection portion 701 is vertically protruded from a position corresponding to a position of the hole 710 and the contact portion 702 is formed at the end of the projection portion 701 and inserted into the hole 710. The contact portion 702 is in the shape of a sphere, but not limited thereto. The contact portion may have various shapes. The hole 710 may have a projection in its inside so that the contact portion 702 is forcibly inserted into the hole 710 at a certain position.

[0075] The combination protrusion 700 is combined with the disk drive 10. In this case, no side surface or bottom surface of the disk drive 10 may be in contact with a bracket. In this case, the combination protrusion 700 is in the form of a cantilever and the displacement of its end is analytically shown as
displacement=PL³/3EI  [Equation 6]

[0076] In this case, P is power per the unit area, L is the length of a combination protrusion, E is an elastic coefficient, and I is the moment of second inertia. Namely, in the case the displacement of the disk drive 10 occurs due to an external impact or internal vibration, the combination protrusion 700 in the shape of a cantilever also bends and vibrates itself to be capable of absorbing a part of a load.

[0077] Also, if not only the combination protrusion 700 but also side wall portions illustrated in the first embodiment are extended and in contact with the sideface of the disk drive 10, a buffering ability may be further improved. Namely, the vibration of the disk drive 10 is first buffered by the side wall portions making contact with the disk drive 10 and second, absorbed by means of self-vibration of the combination protrusions 700. Thus, a greater buffering ability may be expected.

[0078] Also, the combination protrusion 700 may be provided on the rear surface of a bracket having a partition wall capable of preventing mutual interference by electromagnetic waves as illustrated in the second embodiment.

[0079] FIG. 14 is a partial sectional view illustrating a modified example of the third embodiment of the present invention. As illustrated in the figure, the disk drive 10 may further have buffer members 800 disposed around the upper and lower portions of the hole 710. The buffer member 800 is capable of absorbing a vertical vibration. The buffer members 800 may have elasticity and be provided to the upper and lower portions of the disk drive 10. Also, the buffer member 800 may be provided between a bracket and the sideface of the disk drive. Namely, double buffering effects may be achieved by using the buffering members 800 and the combination protrusions 700 together.

[0080] A bracket according to the present invention can not only effectively protect a disk drive from an external impact, but also reduce cost since the bracket can be mass produced by injection molding.

[0081] Also, a bracket according to the present invention has a low rigidity and its buffering ability is improved by reducing the natural frequency.

[0082] Also, since a bracket according to the present invention has an improved buffering ability without installing a buffer member or vibration blocking mount, the size of the bracket can be manufactured small. Accordingly, the bracket is applicable to an electric device such as a portable device which is frequently exposed to an external impact and has a small installation space.

[0083] Also, a bracket according to the present invention can effectively protect a disk drive from a second impact occurring when the displacement of the disk drive is large due to a huge external impact.

[0084] Also, a bracket according to the present invention can buffer a vibration of a disk drive by using a combination protrusion in the shape of a cantilever.

[0085] Also, a bracket according to the present invention not only has an improved buffering ability but also prevents interference between circuits positioned on the bracket.

[0086] While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.