JPS61115279A - Positioning device of head - Google Patents

Abstract

PURPOSE:To correct a thermal track with an extremely simple constitution and to obtain the magnetic disk of a high recording density by checking previ ously the relation of changes in the relative position between a track for infor mation and a head with the aid of temperature and the radius direction on a disk of the head and then incorporating the positioning device of the head. CONSTITUTION:Previously, the relation of changes in the relative position of the track for information and the head is incorporated in the memory means of the positioning device of the head with the aid of the temperature and the radius direction on the disk of the head. Then a temperature sensor detects the temperature of a current disk drive means, and positions of the track for information and the head are corrected from the position in the radius direction on the disk of the head. Namely, a temperature detection part 2 outputs a signal coresponding to the temperature of a magnetic disk drive means, while a microprocessor 7 reads out a correction data corresponding to said tempera ture from a table (not shown) and transmits a signal to a motor control circuit 9 through a digital/analog conversion part 8 for correcting the position of the head relating to the information track and executing the positioning.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a head positioning device for a magnetic disk drive.

[Technical Background of the Invention and Problems Therewith] In high-density magnetic disk drives, the most important reason for restricting the improvement of the radial density of the disk is that there is a limit to the positioning accuracy of the head on the disk. In other words, when information is recorded on a disk and then read out after a certain period of time, it is necessary for the head to accurately trace the track of the recorded information. In this case, the physical dimensions of the disk drive means change with temperature, causing a problem of so-called thermal off-track, in which the head and the information track no longer match. In consideration of such thermal off-tracks, it is necessary to provide a certain degree of space between adjacent information tracks.

Traditionally, there have been two methods to deal with dimensional changes due to thermal off-track.One is to reduce the relative position of each component in a disk drive so that the relative position of each component does not change even if the temperature of each component changes. The other method is to use a temperature sensor to detect the initial temperature of the disk drive, as described in Utility Model Application Laid-open No. 59-95457, for example. This is a method of controlling the position of the head by using a timer to approximate the temperature change over time until the temperature of the disk drive reaches saturation.

Among the conventional head positioning methods described above, the method of selecting the material of the component parts has the disadvantage of complicating the design, and the method of combining a temperature sensor and a timer has the disadvantage of complicating the configuration. there were.

[Object of the Invention] The present invention relates to a head positioning device that improves the head positioning means for correcting the change in the relative position between the information track and the head due to the conventional thermal off-track as described above. The purpose is to obtain a practical head positioning device with a simpler structure.

[Summary of the Invention] The head positioning device of the present invention includes a method in which the relationship between changes in the relative position of the information track and the head is investigated in advance based on the temperature and the radial position of the head on the disk, and the result is incorporated into the head positioning device. This head positioning device detects the current temperature of the disk drive means using a temperature sensor, and corrects the information track and the head position based on the radial position of the head on the disk.

[Embodiments of the invention] Next, the present invention will be explained in detail with reference to the drawings.

Figure 1 shows the relative distance between the information track and the head at the first and second temperatures.The vertical axis represents the distance of the deviation, and the horizontal axis represents the position in the radial direction of the disk. It is something that SO indicates the relative distance of deviation at the first temperature and corresponds to the reference position, and indicates a state in which the relative distance of deviation is zero regardless of the position of the head in the radial direction of the disk. . Also, Sl and Sl are the second
It shows the relative distance of deviation when the temperature is . Here, reference numeral 81 indicates a case in which the deviation increases in the positive direction toward the outside in the radial direction of the disk, and Sl indicates a case in which the deviation increases in the opposite direction to Sl. When the second temperature is higher than the first temperature, whether the shift occurs in the direction indicated by S1 or the direction indicated by S1 is determined by the combination of materials of the constituent elements of the disk drive means, and the disk drive means is assembled. The direction and distance of the shift are uniquely determined at this stage.
Moreover, it is resilient depending on the temperature.

In FIG. 2, the vertical axis shows the absolute value of the deviation between the information track and the head, and the horizontal axis shows the radial position of the disk, and the temperature of the disk drive means is Too, T11.
It shows how the absolute field of deviation changes when TI2, 7+i, and TI4.

Here, in order to quantitatively clarify the distance of misalignment between the information track and the head when the temperature changes, the information recording area r for the total radius R of the disk 1 is changed from rl to r8 as shown in FIG. Each divided area is divided into 1 to 6. By doing so, a table as shown in FIG. 4 can be created from the graph in FIG. 2.

The table shown in Figure 4 shows the temperature in the vertical direction and the block position on the disk in the horizontal direction.If you know the current temperature and which block on the disk the head is on, you can calculate the position of the head It becomes clear whether corrections should be made. Incidentally, when the detected temperature is between the temperature T+o and TI4 shown in the table, it is represented by the closest temperature in the table.

FIG. 5 is a block diagram of the basic configuration of the magnetic disk drive means and the head positioning device.

2 is a temperature detection section. The temperature detection section 2 outputs a voltage according to the temperature. 3 is an analog-to-digital converter. 4
is the disk control unit. The disk-control unit 4 controls the magnetic disk drive itself and receives data and control signals from an external interface bus by controlling the transfer line 5 and the recording/reproducing head 6, the details of which are well known and will not be explained in detail. is omitted.

7 is a microprocessor. microprocessor 7
includes a signal input/output section connected thereto and a storage section for storing programs and data for processing. This storage section contains data corresponding to the table shown in FIG. 4 mentioned above.

8 is a digital-to-analog conversion section. This converts the disk signal output from the microprocessor 7 into an analog signal. Reference numeral 9 denotes a motor control circuit that controls a head drive motor 1o that drives the head.

The flow of signals in the block diagram shown in FIG. 5 will be explained. The disk controller 4 outputs a drive signal to the microprocessor 7 in response to an external request.

The microprocessor 7 receives the signal and controls the motor control circuit 9 to move the head 6 to the head position on the disk specified by the disk control section 4.

The temperature detection section 2 outputs a signal corresponding to the temperature of the magnetic disk drive means, and the microprocessor 7 reads correction data corresponding to the temperature from the table shown in FIG. 4 and controls the motor via the digital-analog conversion section 8. A signal is sent to the circuit 9 for correcting and positioning the head position relative to the information track.

FIG. 6 shows that the microprocessor 7 receives a temperature signal from the temperature detection section 2, and also receives the temperature signal from the head 6 from the disk control section 4.
This figure shows the flow from receiving a signal specifying the position on the disk to sending a signal for correcting the position of the head relative to the information track to the motor control circuit 9 via the digital-to-analog converter 8. That is, in step 11 the temperature is detected, in step 12 the position of the head on the disk is detected, and in step 13 the table shown in FIG. It is extracted and output to the digital-to-analog converter 8 in step 14.

FIG. 7 shows the microprocessor 7° digital-to-analog converter 8 shown in FIG. A more detailed configuration of the motor IIItI circuit 9° head drive motor 10 is shown.

Reference numerals 20 and 21 included in the motor control circuit 9 are switches, 22 and 23 are drive elements that can control the current flowing through the coils 24 and 25 by signals C1 and C2, and 27 is a reference voltage generator. The head drive motor 10 is a so-called stepping motor and has one set of coils 24.
The signals from drive elements 22, 23 applied to 25 cause the rotation or f'stop. At this time, the rotational angular velocity of the rotor 26 is determined by the number of times per unit time of the current flowing through the coils 24 and 25, and the stopping angle is determined by the number of times per unit time that the current is passed through the coils 24 and 25.
4.25 is determined by the state of the current flowing.

Control for passing current through the coils 24.25 is performed by sending signals Pl, P2 from the microprocessor 7 to the driving elements 22.23.
added as.

When rotating the head drive motor 10, by switching the switch 20.21 to the reference voltage 27, a signal is sent to the drive element 22.23 so that an equal current flows to the coil 24.25. Added at C1 and C2.

To stop the head drive motor 10, press switch 2.
0.21 to the digital-to-analog converter 8, a current controlled to correct the stopping angle of the rotor 26 with respect to the coil 24.25 is caused to flow through the drive element 22.23. A signal like 01. C2 is given.

That is, by controlling the currents flowing through the coils 24 and 25, the stopping angle of the rotor 26 is deviated from the normal stopping angle. This performs corrected head positioning.

[Effects of the Invention] By implementing the present invention, thermal off-track can be corrected with an extremely simple configuration, and a magnetic disk drive with higher recording density can be realized. Furthermore, if the radial direction of the disk is divided into a plurality of blocks and the temperature is also corrected by dividing into a plurality of temperature bands, the burden on the software of the control device is light and practical.

[Brief explanation of drawings]

FIG. 1 is a graph of the relative distances between the head, the information track, and the head at two temperatures, and the horizontal axis indicates the position in the radial direction of the disk. FIG. 2 is a graph of the absolute values of the head and the information track at various temperatures, and the horizontal axis indicates the radial position of the disk. FIG. 3 is a diagram in which the disk is divided into a plurality of blocks in the radial direction, and numbers 1 to 6 indicate the blocks. Figure 4 is a tabular representation of the graph in Figure 2.
1o~T+a represents the temperature, and 6 represents the block in K1~. FIG. 5 is a block diagram of an embodiment of the present invention, 2 is a temperature detection section, 3 is a digital-to-analog conversion section, 4 is a disk control section,
5 is a signal line to the outside, 6 is a head, 7 is a microprocessor, 8 is a digital-to-analog converter, 9 is a motor control circuit, 10 is a head drive motor, and FIG. 6 shows the processing steps of the present invention. FIG. 7 shows details of the motor control circuit 8 and the head drive motor 10, where 20.21 is a switch, 22.23 is a drive element, 24.25 is a coil,
26 indicates a rotor. Agent Patent Attorney Masayoshi Sanhun Figure 1 Figure 2

Claims (1)

[Claims] The relationship between the change in the relative position of the information track and the head based on the temperature and the radial position of the head on the disk is stored in advance in the storage means in the head positioning device, and the current temperature of the disk drive means is determined by the temperature sensor. A head positioning device characterized in that the information track and the head position are corrected based on the radial position of the head on the disk.