JP3106655B2 - Head control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head control method for a magnetic disk having servo information formed in a predetermined area on a data surface.

[0002]

2. Description of the Related Art A magnetic disk drive device records and reproduces information with a slider having a magnetic head slightly flying above the surface of a magnetic disk. The slider flies above the surface of the magnetic disk by an air flow generated on the surface of the magnetic disk.

[0003] Hereinafter, a magnetic head support mechanism and a magnetic head control method of a conventional magnetic disk drive will be described with reference to FIGS. 3, 4, 5 and 6. FIG.

FIG. 3 is a plan view showing a configuration of a support mechanism of a magnetic head of a conventional magnetic disk drive. In FIG. 3, a magnetic disk 1 is fixed to a spindle 2 and rotated by a spindle motor. Reference numeral 3 denotes an arm located outside the rotation range of the magnetic disk 1 and capable of swinging about a pivot parallel to the rotation center of the spindle 2. 4 is a flexure fixed to the arm 3. A magnetic head 5 is fixed to the flexure 4 via a gimbal. The gimbal is provided to make the magnetic head 5 follow the undulation of the magnetic disk 1. Further, the shape of the support mechanism of the magnetic head is an in-line type having no offset angle between the direction connecting the center of the magnetic head 5 and the pivot and the longitudinal direction of the slider.

FIG. 4 schematically shows a recording pattern of a magnetic disk. In FIG. 4, reference numeral 6 denotes a servo sector, 7 denotes a data sector, and 6 and 7 form a sector 8. Each surface of the magnetic disk, that is, each track of the upper surface and the lower surface, is divided into sectors 8 provided at equal angular intervals with respect to the rotation center of the spindle. And
Each sector includes, as shown in FIG.
It comprises a servo sector 6 magnetically embedded in the AGC section 10, the zone section 11, and the servo information section 12, and a data sector 7 for recording and reproducing data.
Note that recording of the servo sector 6 by the magnetic head is prohibited. Since the DC erase section 9 does not generate a reproduced signal even when the magnetic head passes through the DC erase section, it serves as a reference for detecting the zone section 11 and the servo information section 12 located after the DC erase section. AGC unit 10
Is for adjusting the gain of the recording / reproducing circuit. The zone section 11 is for determining the zone of the magnetic disk, that is, the inner and outer peripheral areas and the data area.
In the servo information section 12, speed information for moving the magnetic head to the target track and position information for positioning the magnetic head on the target track are provided at equal angular intervals. The speed information is composed of a dibit pattern having a period of a plurality of tracks, and the position information is composed of burst signals alternately embedded in data tracks adjacent in the radial direction of the magnetic disk.

FIG. 6 is a block diagram showing the configuration of a control circuit for detecting servo information from a magnetic disk drive device in which servo information is embedded in each surface as described above and positioning a magnetic head on a target track. .

[0007] A signal reproduced by the magnetic head 5 from the magnetic disk 1 having a track to be accessed for recording / reproducing data by the magnetic head changeover switch 13 is amplified by the reproducing amplifier 14, and then the signal of each sector is read. The DC erase section 9 located at the head is detected by the DC erase detection circuit 15. Then, in synchronism with the DC erase, a gate signal having a time width determined at each position of the AGC section 10, the zone section 11, and the servo information section 12 is generated by the gate generation circuit 16, and each signal is extracted. . Further, the speed information for moving the magnetic head to the target track and the position information for positioning the magnetic head on the target track formed in the servo information 12 are peak-held during a period when the gate is opened by the gate signal. The peak value is sequentially held by the circuit 17 and is taken into the CPU 20 via the A / D converter 18 and the I / O port 19, and the speed signal and the position signal are created by the calculation. When the signals are taken out, the gate generating circuit 16 generates a signal having a time width of the data sector 7. This section is
This is a section where data can be recorded / reproduced, and other sections are prohibited from recording by the magnetic head. By repeating the above process according to the rotation of the magnetic disk, servo information is extracted from each data surface, and
U20 calculates the speed signal and the position signal,
The data is input to a VCM driver 23 via an / O port 21 and a D / A converter 22, and drives an actuator 24 having a magnetic head 5 to position the magnetic head on a target track.

However, in this conventional magnetic disk drive device provided with an in-line type magnetic head support mechanism, when the arm rotates, the direction of inflow of air changes, and the magnetic head moves along the longitudinal direction of the magnetic head. As a result, a flow (side flow) occurs from the direction, and the pressure on the air bearing surface decreases, and the flying height of the magnetic head with respect to the magnetic disk decreases, so that good recording / reproducing characteristics cannot be obtained.

In order to solve this problem, Japanese Patent Application Laid-Open No. 63-288485 discloses a method of swinging around a pivot parallel to the rotation center of the magnetic disk outside the rotation range of the magnetic disk. An arm is provided, and a magnetic head for recording / reproducing information to / from a magnetic disk is provided at the end of the arm. An offset angle is set between a direction connecting the center of the magnetic head and the pivot and a longitudinal direction of the magnetic head. However, a head support mechanism that can appropriately maintain the flying height of the magnetic head regardless of the movement of the magnetic head has been proposed.

The above-mentioned magnetic disk drive will be described below with reference to FIGS. 7 and 8.

FIG. 7 is a plan view showing the structure of a support mechanism for the magnetic head of the magnetic disk drive. The shape of the support mechanism of the magnetic head is such that the arm 3 swingable about a pivot parallel to the rotation center of the spindle 2 and the tip of the arm 3 A magnetic head 5 for recording / reproducing information is provided, and a direction connecting the center of the magnetic head 5 and the pivot,
An offset angle is set between the magnetic head and the longitudinal direction. 7, the same reference numerals as those in FIG. 3 denote the same components as those in the conventional configuration. 25 is the distance between the rotation center of the spindle 2 and the rotation center of the arm 3, 26 is the distance between the gap of the magnetic head 5 and the rotation center of the arm 3, and 27 connects the gap of the magnetic head 5 and the pivot. This is the offset angle between the direction and the longitudinal direction of the magnetic head.

FIG. 8 is a diagram showing the relationship between the track position and the yaw angle when there is no offset angle and when the offset angle is applied. In FIG. 8, the horizontal axis indicates the track position of the magnetic head on the magnetic disk, and the vertical axis indicates the yaw angle. The plot with black circles indicates the magnetic disk drive device having the conventional in-line type magnetic head support mechanism. In this case, the plots with white circles are for the embodiment described in this cited reference. In the conventional example, the distance 25 between the rotation center of the spindle 2 and the rotation center of the arm 3 is 80 mm, the distance 26 between the gap of the magnetic head 5 and the rotation center of the arm 3 is 68 mm, The offset angle between the direction connecting the gap and the pivot and the longitudinal direction of the magnetic head is 0 degree, and in this reference example, the distance 25 between the rotation center of the spindle 2 and the rotation center of the arm 3 is 80 mm. ,
The distance 26 between the gap of the magnetic head 5 and the rotation center of the arm 3 is 90 mm, and the offset angle between the direction connecting the gap of the magnetic head 5 and the pivot and the longitudinal direction of the magnetic head is 25 degrees. In the conventional example of the black circle plot, the change in yaw angle with respect to the track position is extremely large, but in the embodiment described in this cited example, the change in yaw angle with respect to the track position is almost zero. Therefore, irrespective of the movement of the magnetic head, the flying height of the magnetic head can be appropriately maintained, so that the recording surface of the magnetic disk can be prevented from being damaged and good recording / reproducing characteristics can be obtained. .

However, the method disclosed in Japanese Patent Application Laid-Open No.
No. 85 does not disclose the arrangement of servo information configured on a magnetic disk, a method of detecting servo information configured on a magnetic disk, and a method of controlling a magnetic head.

[0014]

However, as in the embodiment described in Japanese Patent Application Laid-Open No. 63-288485, the pivot around the pivot parallel to the rotation center of the magnetic disk is moved out of the rotation range of the magnetic disk. A movable arm and a magnetic head for recording / reproducing information to / from a magnetic disk are provided at the end of the arm, and an offset angle is set between the direction connecting the center of the magnetic head and the pivot and the longitudinal direction of the magnetic head. Used for a conventional in-line type magnetic head support mechanism in a magnetic disk drive device equipped with a head support mechanism that can maintain the flying height of the magnetic head properly regardless of the movement of the magnetic head. Even if the servo pattern is used, the magnetic head cannot be moved to the target track at high speed.

Hereinafter, the reason will be described with reference to FIGS. 9 and 10. FIG. FIG. 9 shows the movement trajectory of the magnetic head and the arrangement of the servo patterns of a magnetic disk drive device provided with a conventional in-line type magnetic head support mechanism. In FIG. 9, reference numeral 28 denotes a movement trajectory of the magnetic head, and reference numeral 29 denotes an arrangement of a servo pattern.
In FIG. 9, the same reference numerals as those in FIG. 3 indicate the same components.

FIG. 10 shows the locus of movement of a magnetic head of a magnetic disk drive device provided with an offset angle and the arrangement of servo patterns as in the embodiment described in JP-A-63-288485. is there. In FIG. 10, the same reference numerals as those in FIG. 9 denote the same components.

In FIG. 10, as compared with FIG. 9, the deviation between the movement trajectory 28 of the magnetic head and the arrangement 29 of the servo patterns becomes larger. Therefore, in the configuration shown in FIG. 10, since the difference between the vector in the tangential direction of rotation of the magnetic disk and the vector in the moving direction of the magnetic head is large, the detection time of the servo information following the DC erase unit is shifted to the head position in the radial direction. It changes on the contrary. That is, if the vector in the tangential direction of the rotation of the magnetic disk and the vector in the moving direction of the magnetic head are in the same direction, the servo information following the DC erase unit is shifted backward with respect to the detection gate. If the vector in the tangential direction of rotation of the magnetic head and the vector in the moving direction of the magnetic head are in the opposite directions, the servo information following the DC erase unit is shifted forward with respect to the detection gate. The information detection time changes. The change in the detection time of the servo information is controlled by the DC erase unit in which the detection of the servo information is controlled by time. Therefore, when the position information is provided at equal angular intervals in the servo information unit, the DC erase unit does not. The larger the servo information is, the larger the servo information is, and the larger the moving speed of the magnetic head is. Therefore, even if the magnetic head is moved at a high speed, the servo information does not enter the detection gate, and the servo information cannot be detected.

Therefore, a conventional in-line type magnetic disk drive apparatus provided with a head support mechanism capable of setting an offset angle and appropriately maintaining the flying height of the magnetic head regardless of the movement of the magnetic head. Even if a servo pattern used in the head support mechanism, that is, a servo pattern in which position information is provided at equal angular intervals in the servo information section, the magnetic head cannot be moved to the target track at high speed. .

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a head control method capable of positioning a magnetic head on a target track at high speed and with high accuracy.

[0020]

The present invention SUMMARY OF THE INVENTION In order to achieve the above object, including the servo information after the DC erase portion
Code bits of the track code section
The distance between the positions in the circumferential direction is increased as the distance from the DC erase section increases, and the time width of the gate signal for detecting the track code section included in the servo information after the DC erase section is increased. It is configured to be wider as the distance from the part increases.

[0021]

According to the present invention, the servo information includes
Code bits of the track code section
The distance between the positions in the circumferential direction is increased as the distance from the DC erase section increases, and the distance included in the servo information is increased .
The time width of the gate for detecting the rack code part is D
Since the distance is increased as the distance from the C erase portion increases, the magnetic head operates so as to absorb the fluctuation of the time axis in the servo sector of the servo information when the magnetic head is moved at a high speed.

[0022]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a detailed view showing a recording pattern near a servo sector portion of a magnetic disk according to the present invention. In FIG. 1, 6 is a servo sector, 7 is a data sector,
Sectors 6 and 7 form a sector. The sector is composed of a servo sector 6 magnetically embedded by a DC erase section 9, an AGC section 10, and a servo information section 12, and a data sector 7 for recording and reproducing data. In addition,
In the servo sector 6, recording by a magnetic head is prohibited. The DC erase section 9 is for detecting the servo information section 12 located after the DC erase section 9 by utilizing that no reproduction signal is generated when the magnetic head passes through the DC erase section 9. And the AGC unit 10
Is for adjusting the gain of the recording / reproducing circuit. The servo information section 12 is provided with a track code section 12a for obtaining track address information, and position information 12b for obtaining information on a positional deviation of the magnetic head from the on-track during tracking control. The track code section 12a includes a sync bit S indicating the beginning of the servo information section 12,
An index bit X, a code bit Z for determining the zone of the magnetic disk, ie, the inner / outer circumference area, and the data area, a code bit A, a code bit B and a code bit C, 12 having a period of 36 tracks and a shift of 9 tracks
A code bit D and a code bit E having a track as a cycle and a deviation of 3 tracks, a code bit F having a period of 6 tracks and having a deviation of at least 1.5 tracks from the code bit D, and a period of 3 tracks. Three-phase code bit G, code bit H, code bit I
And the arrangement of each code bit is configured by a dibit pattern that becomes wider as the distance from the DC erase unit increases. The position information 12b is composed of a burst signal a and a burst signal b, and is set so as to have a deviation of a half track with respect to each track of the servo sector 6. Further, between code bit A and code bit B, between code bit C and code bit D, between code bit F and code bit G, and after code bit I, D
A pad P is inserted to prevent the C erase from continuing for a long time.

FIG. 2 shows a reproduced waveform when the recording pattern of FIG. 1 is reproduced by a magnetic head and the position and width of a gate signal for detecting servo information. FIG. 2A
A reproduced signal around the servo sector is denoted by 9, a DC erase section, 10 an AGC section, 11 a zone section, and 12 a reproduced waveform of a servo information section. Further, as described above, the interval between circumferential positions at which each code bit is to be arranged increases as the distance from the DC erase unit increases. FIG.
B is the position and width of the gate for detecting the index bit X, FIG. 2C is the position and width of the gate for detecting the code bit Z, and FIG. 2D is the position and width of the gate for detecting the code bit A. 2E shows the position and width of a gate for detecting code bit B, FIG. 2F shows the position and width of a gate for detecting code bit C, and FIG. 2G shows the position and width of a gate for detecting code bit D. The position and width of the gate,
2H shows the position and width of the gate for detecting the code bit E, FIG. 2I shows the position and width of the gate for detecting the code bit F, and FIG. 2J shows the position of the gate for detecting the code bit G. 2K shows the position and width of a gate for detecting code bit H, and FIG. 2L shows the position and width of a gate for detecting code bit I. In addition, as described above , the
The width of the detection gate signal in the rack code section increases as the distance from the DC erase section increases.

As described above, the code bits of the track code portion included in the servo information after the DC erase portion are arranged.
The distance between the circumferential positions to be performed is made wider as the distance from the DC erase unit increases, and the time width of the gate signal for detecting the track code portion included in the servo information after the DC erase unit is increased. By increasing the distance as the distance from the DC erase unit increases, it is possible to absorb the fluctuation of the time axis within the servo sector of the servo information when the magnetic head is moved at a high speed. An arm that can swing about a pivot parallel to the center of rotation of the arm and a magnetic head that records and reproduces information on the magnetic disk at the end of the arm, and the direction connecting the center of the magnetic head and the pivot And setting an offset angle with the longitudinal direction of the magnetic head to maintain the flying height of the magnetic head properly regardless of the movement of the magnetic head. In a magnetic disk drive device provided with a head support mechanism capable of driving a magnetic head, the servo information can be accurately obtained even when an actuator having the magnetic head is driven at a high speed. It becomes possible.

The control circuit configuration for detecting the servo information from the magnetic disk drive device in which the servo information is embedded on each surface as described above and positioning the magnetic head on the target track is the same as the conventional example of FIG. .

A signal reproduced by the magnetic head 5 from the magnetic disk 1 having a track to be accessed for recording / reproducing data by the magnetic head changeover switch 13 is amplified by the reproducing amplifier 14 and then subjected to servo signal detection. The DC erase section 9 which is input to the circuit and located at the head of each sector is detected by the DC erase detection circuit 15. Then, in synchronism with the DC erase section 9, a gate signal having a time width determined at each position of the zone section 11 and the servo information section 12 is generated by the gate generation circuit 16, and each signal is extracted. Further, a track code portion 12a for moving the magnetic head to the target track formed in the servo information portion and position information 12b for positioning the magnetic head on the target track include:
During the period when the gate is open by the gate signal, the peak value is sequentially held by the peak hold circuit 17,
The data is taken into the CPU 20 via the D converter 18 and the I / O port 19, and is calculated to generate a speed signal and a position signal. When the signals are taken out, the gate generating circuit 16 generates a signal having a time width of the data sector 7. This section is a section where data can be recorded / reproduced, and other sections are prohibited from recording by the magnetic head. By repeating the above process in accordance with the rotation of the magnetic disk, servo information is extracted from each data surface, and is processed by the CPU 20 to generate a speed signal and a position signal. The I / O port 21 and the D / A converter The data is input to a VCM driver 23 via a motor 22 and drives an actuator 24 having the magnetic head 5 to position the magnetic head on a target track.

As described above, according to this embodiment, the track code portion included in the servo information after the DC erase portion is
The interval between the circumferential positions where the code bits should be placed is
As the distance from the DC erase section increases, the track width increases and the track included in the servo information after the DC erase section increases.
The time width of the gate signal for detecting the code
By increasing the distance from the C erase section, the fluctuation of the time axis in the servo sector of the servo information at the time of moving the magnetic head at a high speed can be absorbed. An arm that can swing around a pivot parallel to the rotation center of the magnetic disk and a magnetic head that records and reproduces information on the magnetic disk are provided at the end of the arm, and the center of the magnetic head and the pivot A magnetic disk drive having a head support mechanism that can set an offset angle between the direction connecting the magnetic head and the longitudinal direction of the magnetic head and maintain the flying height of the magnetic head properly regardless of the movement of the magnetic head Even if the actuator with the magnetic head is driven at high speed, the servo information can be obtained accurately and the magnetic head can be operated at high speed and high accuracy. It is possible to position the target track.

[0029]

As is apparent from the above embodiments, according to the present invention, the servo information after the DC erase section is included.
The circumference where the code bits of the track code section should be placed
The distance between the directional positions is increased as the distance from the DC erase section increases, and the time width of the gate signal for detecting the track code section included in the servo information after the DC erase section is increased. By increasing the distance, the fluctuation of the time axis within the servo sector of the servo information when moving the magnetic head at high speed can be absorbed. Arm that can swing about a pivot that is parallel to the center, a magnetic head that records and reproduces information on the magnetic disk at the end of the arm, and the direction connecting the center of the magnetic head to the pivot and the magnetic head An offset angle is set between the head and the longitudinal direction so that the flying height of the magnetic head can be maintained properly regardless of the movement of the magnetic head. In a magnetic disk drive device provided with a support mechanism, a head control method capable of accurately obtaining servo information even when an actuator having a magnetic head is driven at a high speed and positioning the magnetic head to a target track with high speed and high accuracy Can be provided.

[Brief description of the drawings]

FIG. 1 is a detailed view of a servo sector portion of a disk used in a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a waveform diagram showing a positional relationship between a reproduction signal of a servo sector portion and a gate signal for detecting servo information on a disk used in the apparatus.

FIG. 3 is a plan view showing a configuration of a support mechanism of a magnetic head of a conventional magnetic disk drive device.

FIG. 4 is a schematic diagram schematically showing a recording pattern of a magnetic disk of a magnetic disk drive device having a conventional magnetic head support mechanism.

FIG. 5 is a detailed view of a servo sector portion of a disk used in a magnetic disk drive device having a conventional magnetic head support mechanism.

FIG. 6 is a block diagram showing a control circuit configuration for positioning a magnetic head on a target track.

FIG. 7 is a plan view showing a configuration of a support mechanism of a magnetic head of a magnetic disk drive device described in JP-A-63-288485.

FIG. 8 is a diagram illustrating a relationship between a track position and a yaw angle due to a difference in a support mechanism of a magnetic head.

FIG. 9 is a schematic diagram showing a movement locus of a magnetic head and an arrangement of servo patterns in a magnetic disk drive device having a conventional magnetic head support mechanism.

FIG. 10 is a schematic diagram showing a movement locus of a magnetic head and an arrangement of servo patterns in a magnetic disk drive device provided with a magnetic head support mechanism described in JP-A-63-288485.

[Description of Signs] 1 Magnetic disk 3 Arm 5 Magnetic head 6 Servo sector 9 DC erase section 12 Servo information section 12a Track code section 12b Position information 15 DC erase detection circuit 16 Gate generation circuit

Continuation of front page (56) References JP-A-2-44586 (JP, A) JP-A-63-288485 (JP, A) JP-A-56-127980 (JP, A) (58) Fields studied (Int .Cl. ⁷ , DB name) G11B 21/10 G11B 5/596

Claims (1)

(57) [Claims] An arm swingable around a pivot parallel to a rotation center of the magnetic disk outside a rotation range of the magnetic disk; and recording / reproducing of information on the magnetic disk at a tip of the arm. A magnetic head for performing the following, an offset angle is set between the direction connecting the center of the magnetic head and the pivot and the longitudinal direction of the magnetic head, and the flying height of the magnetic head regardless of the movement of the magnetic head A head control method for a magnetic disk drive device provided with a head support mechanism capable of appropriately maintaining the magnetic field , wherein a DC erase unit and servo information for positioning the magnetic head on a target track are information. The code bit of the track code portion included in the servo information is embedded and formed on the same magnetic disk surface as the recording surface.
The distance between circumferential positions where the lasers should be arranged is increased as the distance from the DC erase section increases, and the track included in the servo information after the DC erase section is increased.
The time width of the gate signal to detect Kkukodo unit,
A head control method for increasing the head distance as the distance from the DC erase unit increases.