JP3682268B2 - Disk drive - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a disk drive device such as a magnetic disk device including a disk that rotates at high speed.
[0002]
[Prior art]
Generally, a magnetic disk device includes a magnetic disk disposed in a case, a spindle motor that supports and rotationally drives the magnetic disk, a carriage assembly that supports a magnetic head, a voice coil motor that drives the carriage assembly, a substrate unit, and the like. Configured.
[0003]
The spindle motor has a cylindrical hub, and a plurality of magnetic disks and spacer rings are alternately stacked on the hub. These magnetic disk and spacer ring are fixed to the outer periphery of the hub by a disk clamper attached to the tip of the hub.
[0004]
In such a magnetic disk device, it is necessary to increase the rotational speed of the magnetic disk in order to perform high-speed data processing. Therefore, in recent years, high-speed rotation type magnetic disk devices have been studied. However, when the magnetic disk rotates at a high speed, an airflow in the same rotational direction as the magnetic disk is generated, and a phenomenon called disk flutter in which the magnetic disk vibrates due to the disturbance of the airflow occurs. In this case, the positioning accuracy of the magnetic head with respect to the magnetic disk is lowered, and the recording density is hindered.
[0005]
[Problems to be solved by the invention]
In order to solve the above problems, for example, according to the magnetic disk device disclosed in Japanese Patent Application Laid-Open No. 10-162548, a forced flow from the inner periphery to the outer periphery is generated in the vicinity of the magnetic disk when the magnetic disk rotates. The disk flutter is reduced by forming a circulation channel and suppressing the turbulence of the airflow.
[0006]
In this magnetic disk apparatus, in order to form a circulation flow path, a notch or a taper part for passing air is processed into the hub and spacer of the spindle motor, and at the same time, an air flow is introduced into these notch or taper part. An air introduction path is formed to match the base and top cover of the magnetic disk device.
[0007]
However, in a magnetic disk device that requires a high recording density, the processing accuracy of individual components directly affects the device performance. For this reason, when individual parts are processed to form a circulation flow path, an increase in processing and finishing costs is unavoidable as the number of processing points increases.
[0008]
In addition, in order to prevent the disk flutter described above, a magnetic disk device in which the shape of the top cover is changed or a separate part is installed has been proposed. There are many problems that must be solved, such as ensuring assembly accuracy.
[0009]
The present invention has been made in view of the above points, and an object of the present invention is to provide a disk drive device capable of reducing the vibration of the disk and improving the head positioning accuracy with respect to the disk while suppressing an increase in manufacturing cost. There is to do.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the disk drive device according to the embodiment of the present invention increases the outer diameter of the disk clamper that fixes the disk to the motor hub, and maintains the distance between the disk clamper and the disk optimally. In such a state, the structure in which the disk rotates integrally with the disk rectifies the airflow in the vicinity of the disk and effectively reduces the disk flutter.
[0011]
That is, a disk drive device according to an embodiment of the present invention has a base having an upper opening, a case having a top cover that closes the upper opening of the base, and a rotatable hub and is attached to the base. A motor, an inner hole through which the hub is inserted, and a disc fitted to the outer periphery of the hub; a disc clamper fixed to the end of the hub and holding the disc on the hub; and the disc And a carriage assembly provided on the base and movably supported on the surface of the disk. The disk clamper is fixed to the end of the hub. and is in the center clamp portion holding the above disc is, pairs at the surface and gaps extending out the disc from the clamp portion radially outward And a substantially annular rectifying portion that is opposed to the top cover with a gap therebetween, and the distance between the rectifying portion of the disc clamper and the surface of the disc is set between the disc surface and the rectifying portion. The distance between the head and the rectification unit is set to 0.85 mm or less, and the distance between the top cover and the rectification unit is the minimum interval at which the head cover and the rectification unit do not contact each other. , 0.7 mm or less.
[0012]
According to the disk drive device configured as described above, by providing a rectifying unit in the disk clamper that rotates integrally with the motor hub, the shape of the top cover is not changed, or a dedicated separate member is not added. It becomes possible to rectify the airflow on the disk surface. As a result, even when the disk rotates at high speed, the turbulence of the airflow generated near the disk can be reduced, and the disk flutter can be reduced. Accordingly, it is possible to obtain a disk drive device that suppresses an increase in manufacturing cost, reduces vibration of the magnetic disk, and improves head positioning accuracy with respect to the magnetic disk.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a hard disk drive (hereinafter referred to as an HDD) will be described in detail as a magnetic disk device according to an embodiment of the present invention with reference to the drawings. As shown in FIG. 1 and FIG. 2, the HDD includes a case 10, which is a rectangular box-shaped base 12 having an open top surface and is screwed to the base with a plurality of screws to close the upper end opening of the base. The top cover 11 is comprised.
[0014]
A spindle motor 18 attached to the bottom wall of the base 12 and two magnetic disks 16a and 16b supported and rotated by the spindle motor are disposed in the case 10. Further, in the case 10, a plurality of magnetic heads for recording and reproducing information with respect to the magnetic disks 16a and 16b, a carriage assembly 22 which supports these magnetic heads movably with respect to the magnetic disks 16a and 16b, A voice coil motor (hereinafter referred to as VCM) 24 for rotating and positioning the carriage assembly; a ramp load mechanism 25 for holding the magnetic head in a retracted position away from the magnetic disk when the magnetic head is moved to the outermost periphery of the magnetic disk; A substrate unit 21 having a preamplifier and the like is accommodated.
[0015]
A printed circuit board (not shown) that controls operations of the spindle motor 18, the VCM 24, and the magnetic head is screwed to the outer surface of the bottom wall of the base 12 via the board unit 21.
[0016]
As shown in FIGS. 1 and 2, the carriage assembly 22 includes a bearing portion 26 fixed on the bottom wall of the base 12 and a plurality of arms 32 extending from the bearing portion. These arms 32 are positioned parallel to the surfaces of the magnetic disks 16a and 16b and at a predetermined distance from each other, and extend from the bearing portion 26 in the same direction. The carriage assembly 22 includes an elongated plate-like suspension 38 that can be elastically deformed. The suspension 38 is configured by a leaf spring, and the base end thereof is fixed to the distal end of the arm 32 by spot welding or adhesion, and extends from the arm. Each suspension 38 may be formed integrally with the corresponding arm 32.
[0017]
A magnetic head 40 is attached to the extended end of the suspension 38. The magnetic head 40 has a substantially rectangular slider and a recording / reproducing MR (magnetic resistance) head formed on the slider, and is fixed to a gimbal portion formed at the tip of the suspension 38 . Four magnetic heads 40 mounted on the suspension 38, respectively, two by two located opposite each other, are disposed so as to sandwich the respective magnetic disk from both sides.
[0018]
On the other hand, the carriage assembly 22 has a support frame 45 extending from the bearing portion 26 in the direction opposite to the arm 32, and the voice coil 47 constituting a part of the VCM 24 is supported by the support frame. The support frame 45 is integrally formed on the outer periphery of the voice coil 47 with synthetic resin. The voice coil 47 is positioned between a pair of yokes 49 fixed on the base 12 and constitutes the VCM 24 together with these yokes and a magnet (not shown) fixed to one of the yokes. When the voice coil 47 is energized, the carriage assembly 22 rotates around the bearing portion 26, and the magnetic head 40 is moved and positioned on desired tracks of the magnetic disks 16a and 16b.
[0019]
The ramp loading mechanism 25 includes a ramp 51 provided on the bottom wall of the base 12 and disposed outside the magnetic disks 16 a and 16 b, and a tab 53 extending from the tip of each suspension 38. When the carriage assembly 22 rotates to the retracted position outside the magnetic disks 16a and 16b, each tab 53 engages with the ramp surface formed on the ramp 51, and is then lifted by the ramp surface inclination and magnetically. Perform the head unload operation.
[0020]
As shown in FIGS. 1 and 2, the magnetic disks 16a and 16b are formed with a diameter of 65 mm (2.5 inches), have an inner hole 42 in the center thereof, and have magnetic recording layers on the upper and lower surfaces. ing. The spindle motor 18 is constituted by an outer rotor type spindle motor. The spindle motor 18 includes a cylindrical hub 44 that functions as a rotor, and two magnetic disks 16a and 16b are coaxially fitted to the hub, and a predetermined length is set along the axial direction of the hub. Laminated at intervals. The magnetic disks 16a and 16b are rotationally driven integrally with the hub 44 by the spindle motor 18 at a predetermined speed.
[0021]
More specifically, a flange 50 that functions as a disk receiving portion is formed on the outer periphery of the lower end portion of the rotatable hub 44. The spindle motor 18 is fixedly arranged at a predetermined position in the case 10 by screwing the motor bracket 52 to the bottom wall of the base 12.
[0022]
The two magnetic disks 16 a and 16 b are fitted on the outer peripheral surface of the hub in a state where the hub 44 is inserted into the inner hole 42 and stacked on the flange 50. In addition, a spacer ring 54 is fitted on the outer periphery of the hub 44 and is stacked with being sandwiched between the magnetic disks 16 and 16b . The magnetic disks 16 a and 16 b and the spacer ring 54 are fastened and fixed to the hub 44 by a disk clamper 56 screwed to the upper end surface of the hub 44. The disk clamper 56 is rotationally driven integrally with the hub 44 and the magnetic disks 16a and 16b.
[0023]
The disc clamper 56 is integrally provided with a disc-shaped clamp portion 58 having an outer diameter slightly larger than the diameter of the hub 44 and a substantially annular rectifying portion 60 extending radially outward from the clamp portion. The disc clamper 56 is integrally formed by, for example, bending a stainless steel plate having a thickness of about 0.6 mm.
[0024]
The clamp portion 58 is screwed and fixed to the hub 44 by a screw 57 and is in close contact with the upper end surface of the hub. The outer peripheral portion of the clamp portion 58 is in contact with the upper surface of the central portion of the upper magnetic disk 16 a and presses the two magnetic disks 16 a and 16 b and the spacer ring 54 toward the flange 50 of the hub 44. Thus, the magnetic disks 16a and 16b and the spacer ring 54 are sandwiched between the flange 50 and the clamp portion 58, and are fixedly held on the hub 44 in a state of being in close contact with each other.
[0025]
The rectifying unit 60 of the disk clamper 56 is formed one step higher than the clamp unit 58 and faces the surface of the magnetic disk 16a with a predetermined gap. The surface of the rectifying unit 60 facing the magnetic disk 16a is formed in a smooth plane. The distance between the rectifying unit 60 and the surface of the magnetic disk is set to the minimum as long as the magnetic head 40 and the carriage assembly 22 moving on the magnetic disk 16a and the rectifying unit 60 do not interfere with each other. For example, this interval is set to 0.85 mm or less, and is set to 0.85 mm in the present embodiment. Further, the distance between the rectifying unit 60 and the inner surface of the top cover 11 is set to a minimum gap where the rectifying unit and the top cover do not contact each other, and the dimension is set to 0.7 mm or less. In this embodiment, it is set to 0.7 mm.
[0026]
The outer peripheral radius d of the rectifying unit 60 is 50 to 110% of the outer peripheral radius D of the magnetic disk, preferably 75 to the outer diameter of the magnetic disk in consideration of the rectifying effect of the rectifying unit and interference with other components. It is formed to 100%. In the present embodiment, the outer peripheral radius d of the rectifying unit 60 is set to about 90% of the outer peripheral radius D of the magnetic disks 16a and 16b.
[0027]
According to the HDD configured as described above, the magnetic disk and the top cover 11 are increased by increasing the outer peripheral radius of the disk clamper 56 that fixes the magnetic disks 16a and 16b to the same extent as the outer peripheral radius of the magnetic disk. Can be effectively reduced by the disk clamper. At the same time, the rectifying unit 60 of the disk clamper 56 is close to the magnetic disk 16a as long as it does not interfere with the magnetic head 40 and the carriage assembly 22. The disk clamper 56 is screwed to the hub 44 and rotates integrally with the magnetic disks 16a and 16b. Therefore, the airflow on the surface of the magnetic disk can be rectified by the disk clamper 56 having the rectifying unit 60 without changing the shape of the top cover or adding a separate member.
[0028]
As a result, even when the magnetic disks 16a and 16b rotate at high speed, the air flow generated in the vicinity of the magnetic disk, in particular, the air flow between the magnetic disk and the top cover is rectified to reduce disk flutter due to the turbulence of the air flow. Can do. As a result, it is possible to obtain an HDD that suppresses an increase in manufacturing cost, reduces vibration of the magnetic disk, and improves head positioning accuracy with respect to the magnetic disk.
[0029]
HDDs equipped with the disk clamper according to the above-described embodiment and HDDs equipped with a conventional disk clamper were prepared, and the disk flutter in the direction perpendicular to the magnetic disk surface was measured for each HDD. FIG. 3A shows the measurement result of the HDD according to the present embodiment, and FIG. 3B shows the measurement result of the conventional HDD. Moreover, the result of having expanded and compared the part shown by the circle A of these measurement results is shown in FIG. The disk flutter was measured using a laser Doppler vibrometer (LDV), and the spectrum of each frequency was measured with an FFT analyzer.
[0030]
In FIG. 3A and FIG. 3B, the spectrum peak includes an integral multiple of the rotational speed due to the undulation of the magnetic disk surface and the like, and a disk flutter component of vibration caused by airflow turbulence. Yes. In FIG. 4, the three locations indicated by circles are peaks due to the disk flutter component, and it can be seen that the disk flutter in the HDD according to the present embodiment is reduced by about 5% as compared with the conventional HDD. .
[0031]
The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. For example, in the above-described embodiment, the configuration including two magnetic disks has been described. However, the number of magnetic disks can be increased or decreased as necessary. The present invention is not limited to a magnetic disk device, but can be applied to other disk drive devices.
[0032]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a disk drive device capable of reducing the vibration of the disk while suppressing an increase in manufacturing cost and improving the positioning accuracy of the head with respect to the disk. .
[Brief description of the drawings]
FIG. 1 is a plan view showing the inside of an HDD according to an embodiment of the present invention.
FIG. 2 is a sectional view showing the HDD case, spindle motor, and magnetic disk.
FIG. 3 is a diagram showing measurement results of disk flutter of the HDD according to the embodiment and the conventional HDD, respectively.
FIG. 4 is a diagram showing a comparison of measurement results of disk flutter of the HDD according to the embodiment and the conventional HDD.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Case 11 ... Top cover 12 ... Base 16a, 16b ... Magnetic disk 18 ... Spindle motor 22 ... Carriage assembly 40 ... Magnetic head 44 ... Hub 56 ... Disk clamper 58 ... Clamp part 60 ... Rectification part

Claims (3)

A base having an upper opening, and a case having a top cover closing the upper opening of the base;
A motor having a rotatable hub and attached to the base;
Discs each having an inner hole through which the hub is inserted and fitted to the outer periphery of the hub;
A disk clamper fixed to the end of the hub and holding the disk on the hub;
A head for recording and reproducing information to and from the disk;
A carriage assembly provided on the base and movably supporting the head on the surface of the disk,
The disc clamper includes a clamping portion which is fixed to an end portion of the hub holds the center of the disc, with faces at a surface gap extending out the disc from the clamp portion radially outward The top cover and a substantially annular rectifying unit facing each other with a gap between them are integrally provided,
The distance between the rectifying part of the disk clamper and the surface of the disk is set to 0.85 mm or less, with the minimum distance at which the head moving between the disk surface and the rectifying part does not contact the rectifying part. ,
2. The disk drive device according to claim 1, wherein the distance between the top cover and the rectifying unit is set to a minimum interval at which the top cover and the rectifying unit do not contact each other and is set to 0.7 mm or less.   2. The disk drive device according to claim 1, wherein an outer diameter of the rectifying portion of the disk clamper is 50 to 110% of the outer diameter of the disk.   3. The disk drive device according to claim 2, wherein an outer diameter of the rectifying portion of the disk clamper is formed to be 75 to 100% of the outer diameter of the disk.

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