JPH01173311A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent an off-track from being generated due to the deformation of a head arm even when an integrated circuit is heated at a recording time by fitting the integrated circuit to the head arm so as to be positioned in a side which is inner than the outermost circumference of a magnetic gap during recording operation at least. CONSTITUTION:An integrated circuit 6 is loaded on a head arm 4 and the recording and reproducing of information are controlled by the instruction of a controlling device. Then, the writing and reading of a signal to a magnetic head 3 are executed. At the recording time, the integrated circuit 6 is fit to the head arm 4 so as to be positioned in the side inner than the outermost circumference of a magnetic disk 1. Even when the integrated circuit 6 is heated at the recording time, since a high speed air flow is generated in the magnetic disk 1 with being accompanied the high speed revolution of the magnetic disk 1, the quantity of heat to be generated in the integrated circuit 6 is speedily cooled by this high speed air flow and the head arm 4 does not get to be deformed. Accordingly, the off-track can be prevented from being generated by the deformation of the head arm 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and particularly to a magnetic disk device that can realize highly accurate positioning of a magnetic head device.

[Conventional technology]

Magnetic disk drives are increasing in capacity and density year by year.
Both the linear recording density and the track direction recording density are becoming increasingly higher. In order to improve linear recording density, it is necessary to efficiently amplify and transmit minute signals recorded on magnetic disks.

Therefore, in recent magnetic disk devices, for example,
As shown in the publication, an integrated circuit for controlling recording and reproduction is mounted on the head arm to suppress the attenuation of minute signals as much as possible. Further, in order to improve the recording density in the track direction, high positioning accuracy on the order of submicrons is required. Therefore, it is necessary to reduce the vibration of the magnetic head positioning actuator and to develop an actuator that is less deformed. In particular, in order to achieve high-precision positioning of lpm or less, even minute temperature non-uniformities around the actuator and between the magnetic disks can cause positioning errors, so it is necessary to consider such errors. There is. That is, when the above-mentioned temperature distribution changes between data recording and data reproduction, a difference in thermal expansion occurs in accordance with the temperature difference, and a positional shift due to temperature, so-called thermal off-track, occurs.

Therefore, it has become necessary to give sufficient consideration to the heat generated by the integrated circuit mounted on the head arm.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, sufficient consideration is not given to the phenomenon that the head arm is deformed due to heat generated by the integrated circuit, resulting in a decrease in positioning accuracy.

For example, as shown in FIG. 4, one servo head 3a and Φ
Consider a case where data is recorded in the order of head numbers 0 to +7 in a magnetic disk device comprising eight data heads 3b numbered 0 to +7. When recording (writing) data, a write W current (several tens of mA) necessary to magnetize the magnetic material on the magnetic disk surface flows through the integrated circuit, so Joule heat is generated depending on the internal resistance of the integrated circuit. occurs. In addition, in Fig. 4, 1 is a magnetic disk,
2 is a rotating spindle, 4 is a head arm, 5 is a carriage, and 6 is an integrated circuit.

First, when writing the head number ΦOK data, the head arm 6
Since the specific heat is smaller and the heat conduction is larger, the integrated circuit 6
Most of the heat generated is transmitted to its own head arm (in this case, the head arm of φ0) 4. As a result, a thermal expansion of length ΔL occurs in the +0 head arm 4. however,
There is a slight delay in the way this heat is transmitted, so the first
During writing by the zero magnetic head, the head arm 4 hardly extends. On the other hand, the servo head 3a.

A servo control circuit (not shown) performs a position control operation so that the error on the servo track is zero, and during the initial writing by the +0 magnetic head, thermal expansion of the head arm of the servo head 3a is also prevented. Since it can be considered as zero, the data 3C of the head number O is obtained on the same radius of the servo head 3ah at that time. Then, when the writing of +0 is completed, as shown in the wjS diagram, +
The magnetic head 0 is at a position extended by the above extension amount ΔL. The heat generated in the integrated circuit 6 of φO is gradually transferred to the other head arms 4 through the carriage 5.
At the end of writing +0, other head arms 4 near +0 (for example, φ2.+3) also undergo thermal expansion by an extension amount Δt.

Here, the amount of thermal expansion Δt due to writing of head number + 0
Before the problem is resolved, ≠1. ÷2゜÷3.・・・・・・
..., when writing data with a +7 magnetic head,
An expansion amount of Δt is added to each head arm 4 one after another,
As shown in FIG. 6, the data is recorded on the magnetic disk 1 at a position deviated from the normal track position. In addition,
The heat generated by the integrated circuit during each write is gradually transferred to the head arm 4 of the servo head 3a through the carriage 5, and thermal expansion is added to the servo head. As a result of the servo control to determine the track position, the off-track error that actually occurs in the data magnetic head is smaller by the thermal expansion of the head arm of the servo head 3a than by the addition of Δt. Track deviation as shown in the figure still occurs.

On the other hand, since the current flowing through the integrated circuit 6 during reproduction (reading) is extremely small, the amount of heat generated is also extremely small, and no thermal expansion occurs during recording (writing). Therefore, the off-track amount of each magnetic head is as shown in FIG. Also, change the writing order to head number + 7.46. +5
．． . . . If +0 is reversed, the off-track amount also shows the opposite tendency, as can be easily inferred. In this manner, off-track occurs due to heat generated by the integrated circuit during writing, resulting in deterioration of positioning accuracy. NaO9φ1, +2. . . . If the writing interval by each magnetic head is set to be sufficiently spaced, for example, at 30 second intervals, the thermal expansion Δt will not be added one after another. Processing speed will decrease.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the problems of the prior art described above and to provide a magnetic disk device in which the head arm is not deformed and off-track does not occur even if the integrated circuit generates heat during recording.

[Means for solving problems]

In order to achieve the above object, the magnetic disk device of the present invention has an integrated circuit mounted on a head arm so as to be located inside the outermost periphery of the magnetic disk at least during a recording operation.

[Effect]

The operation based on the above configuration will be explained.

As the magnetic disks rotate at high speed, a high speed air flow of 10 to 60 m/sec is generated between the magnetic disks. Therefore, if an integrated circuit is inserted between the magnetic disks, even if the integrated circuit generates heat during recording, the generated heat will be quickly cooled down by this high-speed air flow and will not deform the head arm. do not have. This can prevent off-tracking due to deformation of the head arm.

Since heat is generated during recording, the integrated circuit is mounted on an arm that is inserted between the magnetic disks, at least during the recording operation, but as mentioned above, there is a slight time delay in the way the heat is transmitted. Therefore, it is desirable to set the mounting position of the integrated circuit at a position where the integrated circuit can be inserted between the magnetic disks at all times, including during head positioning seek operations before and after. Furthermore, it is desirable that the integrated circuit be placed between the magnetic disks not only when writing to the innermost track of the magnetic disk, but also when writing to the outermost track.

〔·Example〕

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

FIG. 1 is a sectional view of a magnetic disk device according to an embodiment of the present invention. In FIG. 1, parts with the same names as in FIG. 4 are given the same reference numerals. A plurality of magnetic disks 1 are held on a spindle 2 and rotated at high speed by an electric motor (not shown). Magnetic head 3 (corresponding to 33, 3b in Fig. 4)
is held by the head arm 4, and is moved in the radial direction of the magnetic disk 1 by the movement of the carriage 5 to perform positioning. Further, the integrated circuit 6 is mounted on the head arm 4,
Recording and reproduction of information is controlled by instructions from a control device (not shown), and signals are written to and read from the magnetic head 3. Figures 2 and 3
The figure shows a perspective view of a magnetic head assembly in an embodiment of the present invention.

In FIG. 2, one head arm 4 is equipped with two magnetic heads and one integrated circuit 6. During recording and reproduction, the integrated circuit 6 controls the two magnetic heads according to commands from a control device (not shown). One of the three is selected and signals are sent and received through the lead wire 7. Furthermore, since the integrated circuit 6 is placed on a line connecting the sliders of the two magnetic heads 3,
The magnetic herad slider and the integrated circuit are located at almost the same position in the longitudinal direction of the arm, and the positioning operation moves the magnetic head 3
While moving from the outer circumference to the inner circumference on the magnetic disk, it is always inserted between the magnetic disks.

In Fig. 3, one head arm 4 has four magnetic heads 3.
and one integrated circuit 6 are mounted on the tower, two magnetic heads installed in the middle of the head arm handle the relatively outer peripheral side of the magnetic disk, and two magnetic heads installed at the tip of the head arm handle the relatively outer peripheral side of the magnetic disk. In charge of relatively inner circumference.

During recording and reproduction, the integrated circuit 6 acts as a control device (not shown).
Select one of the four magnetic heads 3 according to the command,
Signals are sent and received through the lead wire 7.゛Also, since the integrated circuit 6 is arranged on the inner circumferential side of the line connecting the two magnetic RAD sliders for the outer circumferential side, (that is, the magnetic RAD slider for the outer circumferential side and the integrated circuit Since they are located at almost the same position in the direction), they are always inserted between the magnetic disks as in the case of FIG. In this way, in either case, the integrated circuit 6 is arranged to be inserted between the magnetic disks, so even if the integrated circuit 6 generates heat due to the write current during recording, the amount of heat generated is The high-speed airflow that flows between the magnetic disks quickly cools the magnetic disks, and the air is not transmitted to other head arms. Therefore, the head arm 4 is not deformed due to the heat generated by the integrated circuit 6, and no off-track occurs.

〔Effect of the invention〕

As described above, according to the present invention, the integrated circuit is mounted on the head arm so that it is located inside the outermost circumference of the magnetic disk at least during the recording operation, so that the integrated circuit does not generate heat. As the magnetic disk is cooled by the high-speed airflow generated as the magnetic disk rotates, off-tracking due to deformation of the head arm does not occur, and highly accurate positioning is possible. It has excellent effects, such as being able to promote the

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a magnetic disk device according to an embodiment of the present invention, FIGS. 2 and 3 are perspective views of a magnetic head assembly according to an embodiment of the present invention, and FIGS. Start →'IE! -' A cross-sectional view of the magnetic disk device in IL elf, and FIGS. 6 and 7 are explanatory diagrams showing the off-track amount of each magnetic head in Minemasoku-〇Yokosen-Shigetsu. 1...Magnetic disk, 2...Spindle, 3...Magnetic head, 3a...Servo magnetic head, 3b...Data magnetic head , 4
...Head arm, 5...Carriage, 6...Integrated circuit. Figure 1 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A plurality of magnetic disks stacked and attached to a rotating spindle, a plurality of magnetic heads that perform recording and reproduction on the magnetic disks, a plurality of head arms to which the magnetic heads are attached, and the In a magnetic disk drive comprising a magnetic head positioning carriage to which a head arm is attached, and an integrated circuit attached to the head arm to control recording and reproduction by the magnetic head, the integrated circuit is configured to control the magnetic head positioning carriage at least during a recording operation. A magnetic disk device, characterized in that the magnetic disk device is attached to the head arm so as to be located inside the outermost periphery of the magnetic disk. 2. A magnetic head is attached to a position of a predetermined arm length of the head arm, and the integrated circuit is attached at approximately the same position as the magnetic head in the longitudinal direction of the head arm. Magnetic disk device described in section. 3. A magnetic head that handles the inner circumferential side of the magnetic disk and a magnetic head that serves the outer circumferential side of the magnetic disk are installed at positions of different arm lengths in the longitudinal direction of the head arm. 2. A magnetic disk device according to claim 1, wherein said integrated circuit is mounted at substantially the same position as a magnetic head that takes charge of said integrated circuit.