JPH0217864B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an index signal generation device in a disk device.

(Prior art) In a disk device, for example, a magnetic disk device,
One index pulse is generated each time the disk rotates once, and data is written and read using this index pulse as a reference. Therefore, it is necessary to accurately determine the generation position of the index pulse.

Some disks have holes for generating index pulses in the disk itself, and in disk devices using such disks, it is difficult to always accurately determine the relationship between the index pulse position and the data writing/reading position. can.

On the other hand, some disks do not themselves have index pulse generation means, and in disk devices using such disks, a motor for direct drive of the disk,
That is, the index pulse is generated by a spindle motor. FIG. 5 shows an example of this, in which a detection body 2 made of a magnet or a light reflecting plate is attached to the outer peripheral surface of the rotor 1 of a spindle motor, and a Hall element or a light receiving element is installed on the side of the passage of this detection body 2. A sensor 3 consisting of the following is arranged. The rotor 1 is substantially integrally provided with a spindle hub 4 for mounting a disk hub, and the spindle hub 4 is provided with a drive pin 5 that engages with the disk hub. Therefore, the disk whose center hub is placed on the spindle hub 4 is driven to rotate integrally with the rotor 1 by the drive pin 5, and every time the disk rotates once, and therefore every time the rotor 1 rotates once. A sensor 3 detects the magnetic flux of the magnet 2 and outputs this detection signal as an index signal.

Here, the positions of magnet 2 and sensor 3 are set so that the timing of the terminal output of sensor 3 is slightly earlier than the timing of the reference index signal, and as shown in FIG. Sensor 3 by one monostable multivibrator 6
The output signal is delayed and then output as a pulse signal of a predetermined width by another monostable multivibrator 7. FIG. 7 shows the operation of the circuit in FIG. 6. When a detection signal from a Hall element as shown in a is input,
The monostable multivibrator 6 outputs a pulse signal as shown in FIG. 7b having a width of time T set by a resistor R1 and a capacitor C1. The fall of this pulse signal triggers the monostable multivibrator 7, and the monostable multivibrator 7 generates a pulse signal as shown in FIG. 7c with a width of time Td set by resistor R2 and capacitor C2. Output. The output signal of this monostable multivibrator 7 becomes a reference index pulse, and is a signal delayed by the time T set by the monostable multivibrator 6 with respect to the output signal of the sensor 3.

Incidentally, the generation timing of the index pulse that is to be used as a reference must be precisely adjusted. Therefore, conventional methods for adjusting the index pulse generation position include a mechanical method in which the position of the sensor 3 is varied and adjusted, or a delay time using the monostable multivibrator 6 is determined by making the resistor R1 variable in FIG. Electrical methods of adjustment were used.

(Problems to be Solved by the Invention) According to the conventional method of mechanically adjusting the generation position of the index pulse, it is necessary to support the sensor in a movable and finely adjustable manner in order to finely adjust the position of the sensor. This requires a mechanism to adjust the configuration, which results in a complicated configuration and is not easy to adjust.

On the other hand, according to the electrical method of adjusting the delay time, there is a problem that the time constant due to the resistor and capacitor tends to change over time, and the generation position of the index pulse shifts over time. Therefore, it is conceivable to use a digital counter that does not change over time, but using a digital counter has the disadvantage that fine adjustment is difficult and the cost is high.

Furthermore, regardless of whether such mechanical or electrical methods are used, there is a problem in that the index pulse is emitted at a different position when the motor bead changes due to the presence of electrical delay means. The dot was hot.

It is an object of the present invention to easily adjust the index signal generation position and to automate the adjustment.
An object of the present invention is to provide an index signal generating device which can always output an index signal at the correct timing even if the motor speed changes by eliminating the need for intervening electrical delay means.

(Means for Solving the Problems) The present invention provides an index signal generation device for a disk device, which generates an index signal by rotating a disk drive motor, and writes or reads data based on this index signal. A magnetizable magnetic body is provided on the outer peripheral surface of the rotor of the motor, and a magnetizing means is provided opposite to the magnetic body, and the magnetic body has a width in the rotation direction relative to the magnetizing means. The magnetizing means is capable of changing the magnetized position in the rotational direction by changing the magnetization timing for the magnetic body, and the detection signal of the magnetized position of the magnetic body is used as an index signal. It is characterized by

(Function) By magnetizing the magnetic material provided on the outer peripheral surface of the rotor of the disk drive motor and detecting the magnetized position, an index signal can be obtained. The magnetic material described above has an expanse in the rotational direction, and the magnetized position can be changed in the rotational direction, so after the first magnetization, this is detected and its position is confirmed, and the position that should be used as the reference is determined. If there is a deviation, the magnetization is performed again after correcting the deviation, and the detection signal of this magnetized position can be used as an index signal.

(Example) In FIG. 1, a ring-shaped magnetic material 12 such as a ferrite magnet is fitted onto the outer peripheral surface of a rotor 11 of a spindle motor for driving a disk, and the magnetic material 12 is integrally formed with the rotor 11. It is now able to rotate. The magnetic body 12 can be magnetized. It is sufficient that the magnetic body 12 has a certain extent in the rotational direction so that the magnetized position can be changed within a certain range in the rotational direction. Therefore, the magnetic body 12 does not necessarily need to be formed over the entire circumference, but in the illustrated embodiment, it is formed in a ring shape so that it can be magnetized over the entire circumference. A magnetizing head 17 faces the outer circumferential surface of the magnetic body 12, and the magnetizing head 17 magnetizes a part of the outer circumferential surface of the magnetic body 12. It is designed to be detected by an index detection element 13. A spindle hub 14 is integrally provided on the rotating shaft 16 of the rotor 11, and the spindle hub 14 rotates together with the rotor 11. The central hub of the magnetic disk 18 is placed on the spindle hub 14, and when the drive pin 15 formed on the spindle hub 14 engages with the hub of the disk 18, the disk 18 is driven to rotate integrally with the rotor 11. It is becoming more and more common. A magnetic head 19 is in sliding contact with the disk 18, writes data to the disk 18, and writes data to the disk 18.
It is designed to read data written to.

In FIG. 2, the index detection element 1
The output of the magnetic head 19 is waveform-shaped by a shaping circuit 21 and then input to a delay time control circuit 22 and a time difference timing circuit 20. The time difference clock circuit 20 measures the time difference between the magnetized position detection signal of the magnetic body 12 detected by the index detection element 13 and the reference index signal detected by the magnetic head 19, and controls this by delay time. It is designed to be input to the circuit 22. The delay time control circuit 22 first sets a predetermined delay time for the reference index detection signal from the magnetic head 19, outputs the signal after this delay time, and then adds the time difference from the time difference clock circuit to the delay time. A modified delay time is set and a signal is output after this delay time. Delay time control circuit 22
After being amplified by an amplifier 23, the output is applied to a magnetizing head 17, and the magnetic body 12 is magnetized by the magnetizing head 17 according to a delay time set by a delay time control circuit 22.

Next, a magnetization method for generating an index signal according to the above embodiment and the operation of the above embodiment will be explained.

Now, a standard disk for disk device adjustment is used as the disk 18. As shown in FIG. 3a, a reference signal for adjusting the index signal generation position is recorded on this standard disk, and this reference signal is read by the magnetic head 19. . In order to accurately determine the reference position at which the magnetic head 19 starts writing and reading data on the disk, the timing of the index signal detected by the index detection element 13 must be adjusted as shown in FIG. 3b. must exactly match the reference signal detected by the magnetic head 19. Note that the signal itself directly taken out from the terminal of the index detection element 13 does not necessarily have to match the above reference signal, but the signal formed as an index signal based on the output of this index detection element 13 does not necessarily match the above reference signal. must match or be in a prescribed relationship. For this purpose, it is necessary to magnetize the magnetic body 12 at a predetermined timing.

Therefore, first, the delay time control circuit 22
for a certain period of time as shown in Figure 3c.
With a delay of To, amplifier 23, magnetizing head 1
The magnetic body 12 is magnetized through the magnet 7 to form an index pulse generating section. The index detection element 13 detects this index pulse generation part, and the index detection element 13 and the magnetizing head 1
7 are at different positions, the detection output of the index detection element 13 is different from the magnetic body 1 as shown in FIG.
This results in a deviation from the timing of magnetization to 2. Therefore, the time difference t between the detection signal from the index detection element 13 and the reference signal detection signal from the magnetic head 19 is detected by the time difference clock circuit 20.

Next, as shown in FIG. When the detection signal is delayed by time t, To−
t), the magnetic body 12 is magnetized again, and the index pulse generating section is remade. When the index pulse generating section thus recreated is detected by the index detection element 13, the detection signal exactly matches the reproduction output of the standard disc, as shown in FIG. 3f.

In order to erase the pulse generation portion formed by the first magnetization, the direction of current to the magnetization head 17 may be reversed, and the current may be reversed when magnetizing at the corrected position. . By doing so, it is possible to correct the magnetized position and at the same time erase unnecessary pulse generating portions. However, if a means for determining the correct magnetized position is provided, it is not necessarily necessary to erase the first magnetized position. Further, the magnetization position may be corrected any number of times.

As shown in FIG. 4, the magnetic material for recording the index signal is shared with the frequency generator magnet 24 attached to the rotor case 25 for speed control of the spindle motor, and part of it is used for generating the index signal. It is also possible to form a section.

In this way, the index signal generating part is formed on the magnetic material by magnetization at the correct position, so when the disk is placed on the spindle hub and rotated, the index signal is always placed at the correct position relative to the rotational position of the disk. An index signal is output from the detection element, and based on this, data can be written and read from the correct position.

(Effects of the Invention) According to the present invention, a magnetic material is provided on the outer peripheral surface of the rotor of a disk drive motor, and a magnetizing means is provided opposite to the magnetic material, and the magnetic material is magnetized by the magnetizing means. By doing so, an index signal generating section is provided, so that it is possible to generate an index signal by magnetizing it, and the magnetic body has a spread in the rotational direction, so that the magnetized position can be changed in the rotational direction. Because you can change
By changing the magnetized position, the index signal generation position can be easily adjusted, and it is also possible to automate the index adjustment. Furthermore, since a timer is not required in the index signal generation device of the completed disk device, there is no problem that the index signal generation timing changes over time, and the index signal generation timing does not change due to changes in rotational speed. There will be no such thing as change.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention and an example of index signal magnetization, FIG. 2 is a side view of the same embodiment and a block diagram showing an example of an electric circuit for index signal magnetization, and FIG. 2 is a timing chart showing the operation of the electric circuit in FIG. 2, FIG. 4 is a cross-sectional view showing another mounting mode of the magnetic material that can be used in the present invention, and FIG. 5 is an example of a conventional index signal generator. 6 is a block diagram showing a delay circuit used in the conventional index signal generating device as above, and FIG. 7 is a timing chart for explaining the operation of the delay circuit as above. 11... Rotor of disk drive motor, 12...
magnetic material.

Claims (1)

[Claims] 1. In an index signal generation device for a disk device, which generates an index signal by the rotation of a disk drive motor, and writes or reads data based on this index signal, the outer circumferential surface of the rotor of the motor can be magnetized. A magnetic body is provided, and a magnetizing means is provided opposite to the magnetic body, the magnetic body has a width in the rotational direction relative to the magnetizing means, and the magnetizing means has a width relative to the magnetic body. An index signal generating device characterized in that the magnetized position can be changed in the rotational direction by changing the magnetization timing, and the detection signal of the magnetized position of the magnetic body is used as an index signal.