JP2004079108A - Magnetic disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic disk device for reducing the problem in the unloading operation that the tab stops before reaching the final prescribed position of a ramp and it ends, which occurs accompanying the increase of the number of times of loading / unloading operations in the magnetic disk device of a loading / unloading type. <P>SOLUTION: Inside the magnetic disk device, a function of monitoring the number of times of the loading / unloading operations is provided, also the correlation table of the number of times of the loading / unloading operations and the operation speed of unloading is provided, and the control operation of setting the speed of the unloading operation corresponding to the number of times of the loading / unloading operations on the basis of the correlation table is provided. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetic disk device for recording or reproducing information signals on a magnetic disk.
[0002]
[Prior art]
As the performance of computers has improved, the performance of magnetic disk devices has improved, and magnetic disk devices that have been mainly used as external storage auxiliary devices in the field of personal computers and general-purpose computers have also been characterized by recording, Due to the capacity of reproduction and the quick access speed, in recent years, it has been used not only in the field of home electric appliances but also in the field of automobiles, and is expected to spread to these new fields.
[0003]
Although it has been used under static environmental conditions in use in the computer field, in the home electric appliance field and the automobile field described above, more severe conditions are required in terms of use environment.
[0004]
For example, in a magnetic disk drive mounted on an automobile, operation must be guaranteed at an unusually extreme operating environment temperature such as -40 ° C. to + 80 ° C., and not only the operating temperature, but also the anti-vibration characteristics from the outside. On the other hand, it has been required to perform more than before.
[0005]
By the way, in order to achieve a high recording density, techniques such as increasing the rotation speed of the magnetic disk and decreasing the flying height of the magnetic head have also been adopted. The flying height has been decreasing year by year. Contrary to the fact that the flying height has been reduced, a crash problem occurring between the magnetic disk and the magnetic head during the operation of the magnetic disk drive has been highlighted. ing.
[0006]
On the other hand, when the magnetic disk device is at rest or not operating, a load / unload method (also called a ramp load method) is often used in recent magnetic disk devices in order to reduce the crash problem. . In particular, most of small-sized magnetic disk devices use this method.
[0007]
This load / unload type magnetic disk device is provided with a ramp mechanism for retracting the magnetic head near the outer peripheral edge of the magnetic disk, and when the magnetic disk has not reached normal rotation, the magnetic head is attached to the ramp mechanism. The magnetic disk is retracted to protect the magnetic disk from external vibration and impact.
[0008]
However, as the load / unload type magnetic disk device is used, in other words, as the number of load / unload operations increases, a magnetic head is provided at the distal end of the actuator arm in order to retract the magnetic head to the ramp mechanism. Due to the friction generated between the tab and the ramp mechanism, the surface of the ramp mechanism is roughened, and as a result, the coefficient of friction increases, the tab stops in the middle of the ramp mechanism, and the unloading operation is performed until the last operation. There was an incomplete problem without going.
[0009]
FIG. 4 is a plan view of the load / unload type magnetic disk device as viewed from above with the top cover removed, and FIG. 5 illustrates an unload operation in which the tab moves from the magnetic disk surface to the ramp mechanism. It is the schematic diagram shown by sectional drawing.
[0010]
Hereinafter, a conventional magnetic disk drive will be described with reference to FIGS.
[0011]
First, in FIG. 4, the magnetic disk device 100 includes a base plate 10 also serving as a box-shaped case with an open top surface, and a top cover (not shown) that is screwed to the case with a plurality of screws and closes an upper end opening of the case. Have.
[0012]
The base plate 10 has a magnetic disk 11 as a recording medium, a spindle motor 12 as a driving means for supporting and rotating the magnetic disk 11, and a magnetic head 13 for recording and reproducing information on and from the magnetic disk 11. An actuator arm 14 that movably supports the magnetic head 13 with respect to the magnetic disk 11, a voice coil motor (hereinafter referred to as VCM) 15 for rotating and positioning the actuator arm 14, and a magnetic head 13 A ramp load mechanism 16 for holding the magnetic head 13 at a position separated from the magnetic disk 11 when moved to a retracted position on the outermost periphery of the disk 11 and a substrate unit 17 having a head IC and the like are housed.
[0013]
The magnetic disk 11 is coaxially fitted to a hub (not shown) of a spindle motor (hereinafter referred to as SPM) 12 and held by a clamp spring 18. Then, the magnetic disk 11 is driven to rotate at a predetermined speed by the SPM 12.
[0014]
The actuator arm 14 is attached to a bearing 19 fixed on the bottom wall of the base plate 10, and the other end of the magnetic head 13 opposite to the attachment end has an extended support frame 20. And are provided.
[0015]
An elongated plate-like suspension 21 that can be elastically deformed is fixed to the extending end of the actuator arm 14, and the magnetic head 13 is attached to the tip of the suspension 21 via a gimbal unit (not shown).
[0016]
The actuator arm 14 is rotatable about a bearing 19 as a rotation axis, and the magnetic head 13 supported via the suspension 21 is rotated integrally with the actuator arm 14 and the suspension 21 so that the magnetic disk 11 It can be moved to an arbitrary recording information position on the surface and a retreat position described later. Each magnetic head 13 is electrically connected to the board unit 17 via a flexible cable 22.
[0017]
On the other hand, a voice coil 23 is attached to the support frame 20 of the actuator arm 14. The voice coil 23 is disposed between a pair of yokes, which are fixed on the base plate 10 and includes a bottom yoke 24 and a top yoke (not shown). The VCM 15 is mounted together with these yokes and a magnet 25 fixed to one of the yokes. Make up.
[0018]
When the voice coil 23 is energized, the actuator arm 14 rotates, and the magnetic head 13 is moved and positioned on a desired track of the magnetic disk 11.
[0019]
The ramp loading mechanism 16 includes a ramp 26 attached to the bottom wall of the base plate 10 and positioned outside the magnetic disk 11 and a tab 27 protruding from the suspension 21 of the actuator arm 14.
[0020]
The ramp 26 has a guide surface 28 for guiding and supporting a tab 27 functioning as an engagement portion. The guide surface 28 is arranged in accordance with the suspension 21, extends along the radial direction of the magnetic disk 11 to near the outer peripheral edge of the magnetic disk 11, and is arranged on the movement path of the tab 27.
[0021]
In addition, the guide surface 28 is formed with an inclined portion 28a for guiding the tab 27 to a predetermined position and a concave portion 28b for holding the tab 27 at a designated position.
[0022]
According to the conventional magnetic disk drive 100 configured as described above, during normal operation, the magnetic head 13 is moved onto a desired track of the magnetic disk 11 by rotating the actuator arm 14 by the VCM 15, Information is recorded or reproduced on the magnetic disk 11.
[0023]
As shown in FIG. 4, when the magnetic disk drive shifts to the non-operating state, when the actuator arm 14 is turned from the operating position toward the retracted position of the recessed portion 28b by the VCM 15, the rotation is accompanied by this turning. Thus, the magnetic head 13 also moves from the inner circumference to the outermost circumference of the magnetic disk 11. When the magnetic head 13 moves to the vicinity of the outer peripheral edge of the magnetic disk 11, the tab 27 extending from the suspension 21 projects outward from the outer peripheral edge of the magnetic disk 11 and rides on the guide surface 28 of the ramp 26.
[0024]
As a result, the magnetic head 13 is unloaded while being separated from the surface of the magnetic disk 11.
[0025]
Next, the above-described unload operation will be described in more detail.
[0026]
In FIG. 5, the magnetic head 13 located at a specific position on the surface of the magnetic disk 11 starts the unload operation at the position A based on the unload instruction at the set speed V. Then, the tab 27 contacts the inclined portion 28a of the guide surface 28 of the ramp 26 at the position B. When the tab 27 comes into contact with the inclined portion 28a at the position B, the speed V starts to decrease, and when the tab 27 starts to ascend along the inclined portion 28a, the speed V of the tab 27 gradually decreases.
[0027]
Then, when reaching the position T at which the inclined portion 28a ends, the speed V increases and reaches the concave portion 28b of the ramp 26 which is the final stop position of the ramp 26, and the tab 27 stops at the position C.
[0028]
In this position, a stopper (not shown) is provided on a part of the actuator arm 14 so that the actuator arm 14 cannot rotate in the direction in which the tab 27 moves away from the magnetic disk 11 beyond the C position. .
[0029]
At the final stop position C of the ramp 26, the tab 27 is moved away from the magnetic disk 11 in order to prevent the magnetic head 13 from returning or moving due to external pressure such as external vibration or impact. With the VCM 15 controlled, the unload operation ends.
[0030]
[Problems to be solved by the invention]
However, when the number of operations of the loading / unloading operation including the unloading operation increases, the external pressure received when the tab 27 rides on the guide surface 28 of the ramp 26, for example, the distance between the tab 27 and the guide surface 28 is increased. The tab 27 stops halfway along the inclined portion 28a of the guide surface 28 due to the influence of the frictional force.
[0031]
This is because the surface of the guide surface 28 is roughened by the loading / unloading operation, and as a result, the coefficient of friction increases. At the unloading speed V optimized assuming the initial surface state of the guide surface 28, In addition, there is no longer any operating force for breaking down the increased friction coefficient, and the tab 27 stops on the guide surface 28.
[0032]
The present invention has been made in view of the above problems, and provides a magnetic disk drive having a control function of setting an optimal moving speed at the time of unloading of a magnetic head in accordance with the number of times of loading / unloading. With the goal.
[0033]
[Means for Solving the Problems]
In order to achieve the above object, a magnetic disk device of the present invention includes a magnetic disk as a magnetic recording / reproducing medium, a spindle motor for rotating the magnetic disk, and recording information on the magnetic disk. And a magnetic head for performing reproduction, an actuator arm mounted with the magnetic head and moved to a desired cylinder position, a voice coil motor for magnetically driving the actuator arm, and a load / load using a ramp load. A magnetic disk device having an unload mechanism, wherein a function of monitoring the number of times of loading / unloading of the magnetic head is provided, and whenever the number of times of loading / unloading exceeds a specific number, Controlling the voice coil motor so as to gradually increase the unloading speed. To have.
[0034]
Further, in order to achieve the above object, a magnetic disk drive of the present invention has
A correlation table that is set so that the unload speed is increased stepwise according to the number of operations of the load / unload, and refers to the correlation table based on the number of times of load / unload when an unload command is recognized. Then, the unloading speed is determined.
[0035]
Further, in order to achieve the above object, the magnetic disk drive of the present invention includes a correlation table of an optimum speed between the number of times of loading / unloading and the unloading speed. The voice coil motor is controlled such that the unload speed becomes an optimum speed according to the number of times of the load / unload by referring to the correlation table based on the number of times of the load / unload.
[0036]
According to the present invention, the number of loading / unloading operations of the magnetic head is monitored and the speed of the unloading is controlled, so that the problem that the tab stops on the ramp before the end of the unloading operation can be reduced.
[0037]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
[0038]
FIG. 1 is a block diagram of a load / unload type magnetic disk drive according to the present invention. FIG. 2 is a flowchart showing an unload operation of the magnetic disk drive according to the first embodiment of the present invention. FIG. 3 is a flowchart showing an unload operation of the magnetic disk drive according to the second embodiment of the present invention.
[0039]
Since the mechanism of the magnetic disk drive according to the embodiment of the present invention is the same as that of the conventional magnetic disk drive, the description of the magnetic disk drive will be made with reference to FIG.
[0040]
In FIG. 1, the magnetic disk device 100 includes a control unit 50 on the back surface of the base plate 10 for controlling the entire magnetic disk device 100.
[0041]
The control unit 50 is connected by an interface signal line 70 for transmitting and receiving a control signal from a host system 60 such as a PC.
[0042]
The control unit 50 includes a reproduction / recording (R / W) channel unit 51, a hard disk controller unit (hereinafter, referred to as an HDC unit) 52, a VCM / SPM control unit 53, a non-volatile An IC memory (hereinafter referred to as an EEPROM) 54, a buffer memory (hereinafter referred to as a DRAM) 55, and a CPU / control logic unit (hereinafter referred to as a CPU unit) 56 are mounted.
[0043]
The R / W channel unit 51 is a processing unit for the reproduction / recording signal, and encodes the recording data transferred from the host system 60, and converts the reproduction data (RD) from the reproduction signal read by the reproduction head. It has a decoder function for decoding.
[0044]
The HDC unit 52 receives the recording data (WD) and the command transferred from the host system 60 via the interface signal line 70, and reads the reproduced data read from the magnetic disk 11 and reproduced. It has a data transfer function of transferring data to the data transfer unit 60.
[0045]
The HDC unit 52 has an ECC (Error Correction Code) function of the reproduced data in addition to the interface function and the data transfer control function.
[0046]
The VCM / SPM control unit 53 controls the drive of the SPM 12 and the VCM 15 under the control of the CPU unit 56, supplies a drive current, and has a speed detection function when the magnetic head 13 (tab 27) is loaded or unloaded. are doing.
[0047]
The EEPROM 54 is a memory for storing various data necessary for the control processing of the CPU unit 56, and corresponds to the number of times of loading / unloading operations written on the magnetic disk according to the first embodiment. And a correlation table of stepwise unloading speeds, and the unloading speed is determined stepwise each time the number of operations exceeds a specific number.
[0048]
Further, a correlation table between the number of times of load / unload operation and the optimum unload speed used in the second embodiment is also stored here.
[0049]
The number of times of loading / unloading, which is used to determine the unloading speed based on the correlation table, is an operation generally performed in a magnetic disk device. Each time is performed, the number of operations performed is written to a specific position on the magnetic disk.
[0050]
The DRAM 55 is a memory for temporarily storing reproduction / record data controlled by the HDC unit 52 for transfer.
[0051]
The CPU unit 56 includes a microprocessor (CPU) and a logic circuit unit that constitute a main control device of the magnetic disk device 100, and has a function of controlling load / unload operations related to the present embodiment in addition to various control processes. have.
[0052]
Next, a load / unload operation of the magnetic disk device according to the first embodiment of the present invention will be described with reference to a flowchart shown in FIG.
[0053]
In FIG. 2, when the CPU unit 56 receives an instruction from the host 60 and recognizes the unload command (S1a), it is first recorded on the magnetic disk 11. Read system data such as load / unload count. (S2a).
[0054]
When the number of times of loading / unloading is acquired from the system data (S3a), the number of times of loading / unloading is transmitted to the R / W channel unit 51. In the R / W channel unit 51, a target speed is determined from among the stepwise set speeds with respect to the obtained load / unload times based on the correlation table stored in the EEPROM 54.
[0055]
Thereafter, the determined target speed is sent to the CPU unit 56 (S4a). Then, the CPU 56 calculates the control amount of the VCM 15 so as to reach the target speed (S5a), and controls the VCM 15 to reach the target speed via the VCM / SPM control unit 53 (S6a).
[0056]
According to the first embodiment of the present invention, the control unit 50 monitors the number of times of loading and unloading of the magnetic head, and increases the unloading speed in response to exceeding the predetermined number of times. Therefore, the problem that the tab 27 stops on the ramp 26 before the end of the unloading operation can be reduced.
[0057]
Next, a load / unload operation of the magnetic disk device according to the second embodiment will be described with reference to a flowchart shown in FIG.
[0058]
In FIG. 3, when the CPU unit 56 receives an instruction from the host 60 and recognizes the unload command (S1b), first, it reads system data such as the number of times of loading and unloading recorded on the magnetic disk 11 (S1b). S2b).
[0059]
Then, the number of times of loading / unloading is obtained from the system data (S3b).
The acquired load / unload count is sent to the R / W channel unit 51.
[0060]
In the R / W channel unit 51, the optimum setting speed according to the previously acquired load / unload frequency is obtained from the correlation table between the load / unload frequency and the unload optimal speed stored in the EEPROM 54 in advance. It is determined as the target speed (S4b). Thereafter, the determined target speed is sent to the CPU 56 (S5b).
[0061]
Then, the CPU 56 calculates the control amount of the VCM 15 so as to reach the target speed (S6b), and controls the VCM 15 via the VCM / SPM control unit 53 to reach the target speed (S7b).
[0062]
According to the second embodiment of the present invention, in order to optimize the unloading speed based on the correlation table between the number of times of loading / unloading and the optimal speed of unloading stored in the memory unit of the EEPROM 54, The problem that the tab 27 stops on the ramp 26 before the end of the unloading operation, which is caused by the increase in the number of loading / unloading operations, can be reduced.
[0063]
【The invention's effect】
As described above, according to the present invention, the number of loading / unloading operations of the magnetic head is monitored, and the unloading speed is controlled in accordance with the number of loading / unloading operations. To stop the tab from stopping.
[Brief description of the drawings]
FIG. 1 is a block diagram of a magnetic disk drive of a load / unload type according to the present invention.
FIG. 2 is a flowchart showing an unload operation of the magnetic disk drive according to the first embodiment of the present invention.
FIG. 3 is a flowchart showing an unload operation of a magnetic disk drive according to a second embodiment of the present invention.
FIG. 4 is a plan view of the load / unload type magnetic disk drive as viewed from above with a top cover removed.
FIG. 5 is a schematic view showing a cross-sectional view of an unload operation in which a tab moves from a magnetic disk surface to a ramp mechanism.
[Explanation of symbols]
Reference Signs List 10 Base plate 11 Magnetic disk 12 Spindle motor 13 Magnetic head 14 Actuator arm 15 VCM
Reference Signs List 16 Ramp load mechanism 17 Board unit 18 Clamp spring 19 Bearing 20 Support frame 21 Suspension 22 Flexible cable 23 Voice coil 24 Bottom yoke 25 Magnet 26 Lamp 27 Tab 28 Guide surface 28a Inclined part 50 Control part 51 R / W channel part 52 HDC part 53 VCM / SPM control unit 54 EEPROM
55 DRAM
56 CPU / control logic unit 60 host 70 interface signal line 100 magnetic disk drive

Claims (3)

A magnetic disk serving as a magnetic recording / reproducing medium, a spindle motor for rotating and driving the magnetic disk, a magnetic head for recording and reproducing information on and from the magnetic disk, and a magnetic head mounted thereon. An actuator arm for moving to a desired cylinder position, a voice coil motor for magnetically driving the actuator arm, and a magnetic disk device including a load / unload mechanism using a ramp load,
A function of monitoring the number of times of loading / unloading of the magnetic head is provided. A magnetic disk drive for controlling a coil motor. A correlation table that is set such that the unloading speed is increased stepwise according to the number of operations of the load / unload operation, and refers to the correlation table from the number of times of loading / unloading when an unload command is recognized. 2. The magnetic disk drive according to claim 1, wherein the unloading speed is determined. A correlation table for the optimum number of times of the load / unload operation and the unload speed, and referring to the correlation table based on the number of load / unload times when an unload command is recognized; 2. The magnetic disk drive according to claim 1, wherein the voice coil motor is controlled so that the unloading speed becomes an optimum speed according to the number of times of the unloading.

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