JPH0322670B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for adjusting the head position of a disk device for recording and/or reproducing data.

[Conventional technology]

Mechanisms for moving the head of a floppy disk drive in the radial direction of the disk by means of a lead screw are well known. This type of mechanism has a screw connected to a stepping motor, and is configured to move the head carriage in the radial direction of the disk together with a ball pressed into a groove of the screw by a leaf spring. By the way, when the stepping motor is driven by a step signal for positioning the head on a predetermined track of the disk, it is ensured that the head is located on the predetermined track. For this reason, an adjustment disk is used to check whether the head is in the proper position with respect to the adjustment track on the disk, and to adjust the head to the proper position.

[Problem that the invention seeks to solve]

By the way, if the head is in the correct position with respect to the adjustment recording track of the adjustment disk, the head will also be in the correct position with respect to the actual data recording and/or reproduction disk track corresponding to this adjustment recording track. Become. Furthermore, since the screw is constructed so that feeding errors are not accumulated, the head position after multiple rotations of the screw also corresponds to the desired track. However, due to eccentricity of the screw when the lead screw is formed with rotational movement using a machine tool, eccentricity when attaching the screw, etc., a periodic error occurs in which one rotation of the screw is synchronized.

FIG. 6 shows the relationship between the screw rotation angle θ and the head movement distance L. If the screw is formed accurately, the head movement distance L changes linearly as shown by the dotted line, but in reality, the head movement distance changes as shown by the solid line with a period of 2π (one rotation). Therefore, there is a periodic positional deviation (error) between the head and the track on the disk as shown in Figure 7.
occurs. Conventionally, head position adjustment has not been performed taking into account periodic fluctuations as shown in Figure 6.
There is a possibility that head position adjustment is performed on the adjustment track corresponding to the highest or lowest point of the fluctuation range, and in this case, the track position deviation corresponding to twice the amplitude b of the periodic fluctuation 2b is outside the adjustment track. This may occur on the following tracks.

SUMMARY OF THE INVENTION An object of the present invention is to provide a head position adjustment method that minimizes head track position deviation due to the screw.

[Means for solving problems]

A head position adjustment method according to the present invention for solving the above-mentioned problems includes: a rotating device for a recording medium disk; a converting head that faces the disk and converts signals; and a position of the head in the disk radial direction. and a head moving mechanism that includes a screw that rotates following the rotation of the motor and converts the rotational motion of the motor into linear motion of the head to move the head in the radial direction of the disk. A method for adjusting the head position of a disk device equipped with a head position adjustment disk using a head position adjustment disk includes a first adjustment track and (a/2Tp)n tracks from the first adjustment track (where a is the above-mentioned At least a disk for head position adjustment is prepared, and a second integer track provided at a position separated by the pitch of the screw, Tp is the track pitch of the recording medium disk, and n is an integer other than zero, is used for adjusting the head position. The disk is rotated by the rotating device and the head is moved to the first and second adjustment tracks by driving the motor, and the records on the first and second adjustment tracks are transferred to the head. and, based on these reading outputs, at least adjust the angular position of the screw in the rotational direction so that the positional deviation of the head with respect to the first and second adjustment tracks becomes substantially zero or near zero. It is characterized by adjustment.

[Effect]

The number of tracks (a/2Tp) n between the first adjustment track and the second adjustment track in the above invention corresponds to half a revolution (π) of the lead screw or this n times. If the rotational angle position of the screw is adjusted so that the error in the head position with respect to the first and second adjustment tracks set in this way becomes substantially zero, the positional deviation of the head on tracks other than the adjustment track can be made cyclic. The amplitude of the error can be suppressed to less than the amplitude of the actual error.

〔Example〕

Next, a magnetic disk device and a head position adjustment method thereof according to an embodiment of the present invention will be described with reference to the drawings.

The magnetic disk device shown in FIG. 1 records or reproduces data using a disk cartridge 3 consisting of a flexible magnetic disk 1 and its case 2, and a rotating device 4 for the disk 1, The magnetic head 5 is provided with a magnetic head 5 that comes into sliding contact with the disk 1, and a moving mechanism 6 that moves the head 5 in the radial direction of the disk 1. The head moving mechanism 6 is
The carriage 7 supporting the head 5 is driven by a stepping motor 8. In order to convert the rotational motion of the stepping motor 8 into linear motion of the carriage 7, a lead screw type feeding mechanism is provided. That is, a screw 9 is connected to the shaft of the stepping motor 8, and the extension part 1 of the carriage 7 is inserted into the groove 10 of the screw 9.
A ball 12 supported by 1 is engaged, and this ball 12 is pressed against the groove 10 by a leaf spring 13.

The carriage 7 is guided in the disk radial direction by a guide rod 14 and is prevented from rotating. Therefore, when the stepping motor 8 and the screw 9 rotate, the ball 12 is pushed by the groove 10, and the ball 12 and the carriage 7 are displaced in the radial direction of the disk.

In addition, 15 in FIG. 1 is a pad, and the head 5
The arm 16 is disposed opposite to the arm 16 and is attached to an arm 16 supported by the carriage 7. In this embodiment, since it is a single-sided disk device, there is only one head 5, but in the case of a double-sided disk device, another magnetic head is arranged in place of the pad 15.

The stepping motor 8 is fixed to a support substrate 20 with screws 19 using a mounting plate 18 having a long hole 17 as shown in FIG. 2 so that the angular position in its rotational direction can be adjusted. .

By the way, it is necessary that a specific step of the stepping motor 8 correspond to a specific track of the disk 1. For this reason, it is necessary to adjust the head position so that the head 5 corresponds to a specific track on the disk 1 at a specific step of the stepping motor 8. FIG. 4 shows an adjustment disk 21 for making such adjustments. According to the present invention, the adjustment disk 21 is provided with first and second adjustment tracks 22, 23, that is, alignment tracks on a concentric circumference, and burst signals are provided on the inner and outer sides with respect to the track center. A ₁ , A ₂ , B ₁ , B ₂
are recorded respectively. In addition, burst signal
A ₁ , A ₂ , B ₁ , and B ₂ are not recorded in one revolution of the disk 21, but only within a certain angle range.

The mutual center spacing _L12 of the first and second adjusting tracks 22, 23 is determined according to the invention to correspond to the number of a/2Tp tracks. However, a
As is clear from FIG. 3, Tp is the pitch of the screw 9, and Tp is the track pitch of the recording medium disk 1 in FIG. 1, and in this embodiment, Tp is set to a/10. First and second adjustment tracks 22, 23
The fact that the interval L ₁₂ corresponds to the number of a/2Tp tracks means that L ₁₂ =a/2. In short, _L12 corresponds to a feed amount that approximately corresponds to half a rotation of the screw 9.

When adjusting the position of the head 15 shown in FIG. 1 with the adjustment disk 21 shown in FIG. 4, the adjustment disk 21 is attached to the disk device shown in FIG. A step signal is applied to the stepping motor 8, for example at a rate of two steps per track or one step per track, to move the head 5 to the first adjustment track 22. Then, at this head position, the burst signals A ₁ and B ₁ of the first adjustment track 22 are read, and
A reproduced output waveform shown in FIG. 5A is obtained. Then, the stepping motor 8 is operated so that the burst signals A ₁ and B ₁ are substantially equal, that is, the head 5 is placed on the first adjustment track 22 without any displacement.
and adjust the angular position of the screw 9 in the rotational direction. Further, a step signal for making the head 5 correspond to the second adjustment track 23 is given to the stepping motor 8, and the head 5 is moved to the second adjustment track 23.
3 and read the burst signals A ₂ and B ₂ of the second adjustment track 23 to obtain the reproduced output waveform shown in FIG. 5B. Then, the rotation angle positions of the stepping motor 8 and the screw 9 are adjusted so that the error in the position of the head 5 with respect to the first adjustment track 22 becomes substantially zero. Note that in reality, it is difficult to reduce the error to zero, so the error in the first adjustment track 22 is X ₁ = 1-B ₁ /A ₁ and the error in the second adjustment track 23 is X ₂ = 1-B. Adjust so that the absolute values of ₂ /A ₂ are equal to each other near zero. As mentioned above, the first and second adjustment tracks 22 have a spacing corresponding to half the circumference of the screw 9,
When the head 5 is positioned with respect to the screw 23, the position of the head 5 is adjusted at the center of the periodic error caused by the rotation of the screw 9.

When the recording medium disk 1 is mounted on a disk device that has been adjusted as described above to perform recording or reproduction, the maximum value of the error between the head 5 and the track caused by the periodic error caused by the screw 9 is as follows. This is half the fluctuation range (peak-to-peak) of the periodic error caused by the screw 9. For this reason,
During mass production of disk devices, the periodic error due to the screw 9 can be statistically halved compared to the conventional method.

The reason why the error can be reduced by setting the difference in the number of tracks between the first and second adjustment tracks 23, 23 to a/2Tp track will be explained in more detail. Now, as shown in FIG. 3, if the pitch of the screw 9 is a, the moving distance of the head 5 and ball 12 is L, and the rotation angle of the screw 9 is θ, then
If the error is ignored, the following equation holds.

L=aθ/2π...(1) However, in general, the machining accuracy of the screw 9,
It was found that periodic fluctuations as shown in the following equation occur based on installation accuracy, etc.

L=aθ/2π+bsin(θ+α)...(2) In the above equation (2), bsin(θ+α) indicates the periodic fluctuation (error), b is the maximum value of the amplitude of the periodic fluctuation,
α is the initial phase. The moving distance L shown by the solid line in FIG. 6 corresponds to equation (2), and the dotted line corresponds to aθ/2π.

The fact that the head movement distance L does not change linearly with the screw rotation angle means that the positional deviation (error) between the track and the head 5 due to changes in the track position (track number) will be as shown in Figure 7. It means to fluctuate as shown. Conventionally, the head was adjusted to the optimum position for one adjustment track. If the position of the conventional adjustment track is the point where the error waveform in Figure 7 crosses its center line,
T ₄ and when the head is fully positioned with respect to the track in this position,
The maximum value of the error occurring in other tracks is b, which can be kept relatively low. However, in the conventional method, if the position of the adjustment track is determined to correspond to the _T3 point and the head is perfectly positioned with respect to this track, the track deviation (error) of the head of up to 2b on other tracks )
occurs.

In contrast, in the present invention, in order to adjust the head position at two locations, the first adjustment track position _T1 and the second adjustment track position _T2 , the track deviation (error) of the head on tracks other than the adjustment track can be adjusted. ) can be set to b. Now, if the relationship between the error and the first and second adjustment track positions T ₁ and T ₂ according to the present invention before the head position adjustment is as shown by the solid line, then the track position
T ₁ and T ₂ have different errors C ₁ and C ₂ respectively. Therefore, the stepping motor 8 and screw 9 are turned slightly to shift the error waveform to the position shown by the dotted line. Now, assuming that the center line position of the error waveform has zero error, by shifting the waveform to the position shown by the dotted line, the positional deviation (error) between the first and second adjustment tracks and the head 5 can be substantially reduced. becomes zero. The first adjustment track position _T1 and the second
Since the interval between the adjusting track position _T2 and the adjusting track position T2 corresponds to half the rotation of the screw 9, that is, the phase angle π of the error waveform, it is possible to make the errors of both the first and second adjusting tracks substantially zero. be. If the adjustment is made in this manner, an error of at most b or more will not occur in the tracks other than the first and second adjustment tracks.

In the embodiment, the mutual spacing between the first and second adjusting tracks was set to a/2Tp corresponding to the rotational phase angle π of the screw 9, but the mutual spacing between the first and second adjusting tracks was set to 2π, 3π, etc. Even if it is set to (a/2Tp)×2, (a/2Tp)×3, etc. in response to the above, the same head position adjustment as in the case of a/2Tp can be performed.

In addition, in order to obtain the effect of adjusting at the center of the difference (hysteresis error) between when the stepping motor 8 is operated in the step-out direction and when it is operated in the step-in direction, the first adjustment track 2
It is desirable to drive the stepping motor 8 in the step-out direction to move the head 5 to the second adjusting track 23, and to drive the stepping motor 8 in the step-in direction to move the head 5 to the second adjustment track 23.

The invention is not limited to the embodiments described above, but can be further modified. For example, in addition to the first and second adjustment tracks 22 and 23, a third adjustment track and a plurality of adjustment tracks such as a fourth and fifth adjustment track may be provided, and the intervals between these tracks may be set by the lead screw 9.
The track spacing corresponds to a half circumference or an integral multiple of this, and two or more of the plurality of adjustment tracks are used to adjust the positional deviation of the head 5 with respect to these tracks to substantially zero. Good too. Furthermore, the signals written to the adjustment tracks 22 and 23 are not limited to the burst signals shown in FIG. 4, but can be replaced with various signals that can detect track deviations. Further, the adjustment tracks 22 and 23 may be recorded at a plurality of locations during one round or all around.

〔Effect of the invention〕

As is clear from the above, according to the present invention, errors in head position relative to tracks other than the adjustment track can be easily reduced.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing a magnetic disk device according to an embodiment of the present invention, FIG. 2 is a side view showing position adjustment in the rotational direction of the stepping motor shown in FIG. 1, and FIG. 4 is a plan view showing the principle of the adjusting disk according to the present invention, FIG. 5 A and B are waveform diagrams showing the playback output of the disk in FIG. 4, and FIG. FIG. 1 is a diagram showing the relationship between the screw rotation angle and head movement distance in the apparatus, and FIG. 7 is a waveform diagram showing the relationship between track position and error. DESCRIPTION OF SYMBOLS 1... Disk, 4... Rotating device, 5... Head, 6... Moving mechanism, 8... Stepping motor, 9... Screw, 21... Adjustment disk, 22... First adjustment track, 23...Second
adjustment track.

Claims (1)

[Scope of Claims] 1. A rotating device for a recording medium disk, a conversion head that faces the disk and converts signals, a motor for changing the position of the head in the disk radial direction, and a motor that follows the rotation of the motor. Head position adjustment of a disk device including a screw that rotates as a head, and a head movement mechanism that converts the rotational movement of the motor into a linear movement of the head and moves the head in the radial direction of the disk. a first adjustment track, and (a/2Tp)n tracks from this first adjustment track (where a is the pitch of the screw, Tp is the track pitch of the recording medium disc, A head position adjustment disk having at least a second adjustment track provided at a position separated by an integer other than zero (n is an integer other than zero) is prepared, the head position adjustment disk is rotated by the rotating device, and the motor is rotated by the rotation device. moving the head to the first and second adjustment tracks by driving the head, respectively reading the records of the first and second adjustment tracks with the head, and based on the readout outputs thereof. A head position of a disk device characterized in that at least the angular position of the screw in the rotational direction is adjusted so that the positional deviation of the head with respect to the first and second adjustment tracks becomes substantially zero or near zero. Adjustment method. 2. Moving the head to the first adjustment track is done by rotating the motor in one direction, and moving the head to the second adjustment track is done by rotating the motor in the other direction. 2. The head position adjustment method according to claim 1, wherein the head position adjustment method is performed by rotating the head in a direction.