JPH03263659A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To suppress the movement of the entire device due to a seek reaction force by mounting magnetic heads while grouping the plural magnetic heads into two or an even number of actuators and accessing the plural actuators nearly simultaneously. CONSTITUTION:The device is made up of a magnetic disk 1, a spindle 2 supporting and driving the magnetic disk 1 and rotary actuators 4, 4' supporting and positioning magnetic head 3, 3'. Then the actuators 4, 4' are arranged to positions in mirror symmetry with respect to a center axis of the spindle 2. Moreover, a control circuit of the actuators 4, 4' has two sets of servo control circuits only and the two actuators 4, 4' are driven synchronously with each other in a reverse direction and seek the disk at the seek. Thus, reaction forces B, B' of both the actuators 4, 4' at seek are reversed. Then the vibration due to seek reaction force is suppressed.

Description

[Detailed Description of the Invention] [Summary] Regarding magnetic disk devices widely used as file storage devices in information systems, the purpose of this invention is to improve head positioning accuracy by eliminating seek reaction force, and to record information. a plurality of magnetic disks that rotate the magnetic disks, a spindle that rotates the magnetic disks, a plurality of magnetic heads that read and write information, an actuator that positions the magnetic heads, a casing that holds the spindles and actuators, and a head positioning control circuit. In a magnetic disk drive equipped with the above, the plurality of magnetic heads are divided into two or an even number of actuators and mounted, and the plurality of actuators are always accessed almost simultaneously, thereby eliminating seek reaction force. do.

[Industrial Application Field] The present invention relates to a magnetic disk device that is widely used as a file storage device for information systems.

In recent years, technological advances in magnetic disk drives have been remarkable over the past 10 years.
Efforts have been made to increase storage capacity by more than 0 times. For this reason, there has recently been a remarkable trend toward miniaturization of devices, and IGB
(=1000MB) or more is about to be realized.

It is expected that devices will become smaller and larger in capacity in the future, and along with this, in order to quickly process larger amounts of data, faster access and faster rotation are being sought.

[Conventional technology]

Recently, in order to downsize devices, devices with a rotary actuator (also called a swing type), which are more space efficient, have become mainstream. FIG. 6 is a diagram showing an outline of this device. This includes a plurality of magnetic disks 1 for recording information, a spindle 2 for rotating the magnetic disks', a plurality of magnetic heads 3 for reading and writing information, an actuator 4 for positioning the magnetic heads 3, and a spindle 2 for rotating the magnetic disks. The device includes an airtight casing (base system) 5 that holds the actuator 4 and the actuator 4, and a head positioning control circuit (not shown).

[Problems to be Solved by the Invention] In the conventional magnetic disk drive described above, in order to increase the recording density, it is necessary to increase the recording density in the track direction (recently, the latch pitch is on the order of 101M). It is necessary to improve positioning accuracy.

On the other hand, with the miniaturization of devices, the weight of the device has become lighter, and the driving force of the actuator has increased to increase the access speed, so the influence of the reaction force during seek becomes greater, and countermeasures are needed. There is.

That is, as shown in FIG. 6, the reaction force during seek is transmitted to the base system 5 via the magnetic circuit. There is no problem if the mass of the base system 5 is infinite, but in a lightweight device, the base system 5 moves in the direction of the arrow around the center of gravity G due to the reaction force. This causes a problem in that a positioning error of the magnetic head occurs.

In order to reduce the positioning error of the head, for example, the rotation of the spindle should be made to coincide with the center of gravity of the housing (Japanese Patent Application No. 1-27
No. 0450), the casing is supported on a frame by a plurality of anti-vibration supports such as anti-vibration rubber and dampers so as to balance the primary moment around the center of gravity of the casing (Japanese Patent Application No.
There are countermeasures such as No. 240198), but these are not perfect and the occurrence of positioning errors is unavoidable. Another idea is to install an accelerometer in the device to compensate for the movement of the base system (Utility Model Application No. 59-5089), but this is effective, but it requires a special accelerometer and control circuit. be.

SUMMARY OF THE INVENTION In view of the above conventional problems, it is an object of the present invention to provide a magnetic disk device that can improve head positioning accuracy by eliminating seek reaction force.

[Means to solve the problem]

In order to achieve the above object, the magnetic disk device of the present invention includes a plurality of magnetic disks 1 for recording information, a spindle 2 for rotating the magnetic disks', a plurality of magnetic heads 3 for reading and writing information, and a plurality of magnetic heads 3 for reading and writing information. In a magnetic disk drive including an actuator 4 for positioning the magnetic head 3, a housing 5 for holding the spindle 2 and the actuator 4, and a head positioning control circuit, the plurality of magnetic heads 3 are moved by two or an even number of actuators. 4,4'
The plurality of actuators 4゜4'
The present invention is characterized in that seek reaction force is eliminated by always accessing almost simultaneously.

In order to avoid positioning errors caused by this, a dual actuator system was adopted.

A general dual actuator has two sets of actuators with completely independent control circuits, as shown in FIG. 7, in order to avoid access conflicts, and is completely equivalent to two spindles when viewed from the outside. This is the worst case in terms of positioning accuracy, as there may be cases where one actuator is performing R/W while the other actuator is seeking at high speed.

Therefore, in the present invention, unlike a general dual actuator, it is viewed from the outside as one disk (with one logical volume), has only two sets of servo control circuits, and in principle, the two actuators are synchronized when seeking. By seeking in a direction that cancels out each other's seek reaction forces, the reaction forces can be eliminated.

[For production]

The present invention traces the seek reaction force itself back to its source and completely eliminates the movement of the base system.
is a schematic plan view, and (b) is a block diagram.

In the same figure (a), 1 is a magnetic disk, 2 is a spindle that supports and rotates the magnetic disk, 4.4' is a rotary actuator that supports and positions the magnetic head 3, and 0 and 0' are the magnetic disks. This is the center of rotation of the actuator 4.4'. The two actuators 4,4' have a substantially mirror-symmetrical structure, and are arranged at mirror-symmetrical positions with respect to a plane containing the central axis of the spindle 2.

Furthermore, the control circuit of the actuator 4.4' is shown in FIG.
), there are only two sets of servo control circuits, and when seeking, the two actuators 4.4' are synchronized and are directed in opposite directions (if the actuator 4 is in the arrow A direction, the actuator 4' is in the arrow A' direction). It is designed to rotate and seek.

In this embodiment configured in this manner, the reaction forces B and B' of both actuators 4, 4' during seek are in opposite directions, and both translational force and moment are completely eliminated.

Here, operations during track access and cylinder access (reading information of all heads) are as follows.

(a) In the case of track access, R/W is performed from the actuator side that has the head to be read.

(b) In the case of cylinder access, R/W all heads sequentially starting from both actuators.

Here, the heads are numbered serially for both actuators as in the conventional l actuator.

Therefore, when viewed from the outside, it can be regarded as one actuator as in the conventional case.

In this embodiment described above, the seek reaction force is eliminated, but conventionally
There are now two sets of actuators that used to be Mi, which tends to increase costs. However, there are many advantages that make up for it. This will be explained next.

In this embodiment, the servo surface can take the following two types of configurations in common.

(a) The first method is to allocate half the number of head arms 4a to each actuator 4.4' as shown in FIG. 2(a).

(b) Second, as shown in Figure 2(b), the number of head arms is the same as before for each actuator, the stroke is halved, and the data zone of one actuator is set to inner circumference A, and the data of the other actuator is Let the zone be the outer periphery B.

In case (a) above, the moment of inertia of each actuator is approximately X of that of a conventional actuator, which is very advantageous for high-speed access. Furthermore, if the same seek is performed using the same motor as in the prior art, the power consumption will be the same as in the prior art even if the total power consumption is for two actuators.

In case (b), the moment of inertia remains the same, but the stroke becomes A, which speeds up the access (generally,
/7 = 1.4 times faster) and has the advantage of requiring only one servo surface.

As described above, in both cases (a) and (b), a significant increase in speed can be achieved, and the effect is greater than that of a slight cost amplifier.

Next, a second embodiment of the present invention is shown in FIG. In this figure, the same parts as in FIG. 1 are designated by the same reference numerals.

In this embodiment, the two actuators 4 and 4' have the same shape, are arranged to face each other, and the theta direction is opposite (for example, when one actuator 4' seeks from the outer to the inner side, the other The actuator 4 is designed to seek from the inner to the outer. As a result, the reaction forces caused by the moments A and A' generated by the actuators 4 and 4' are oriented in opposite directions to the weight scale and are eliminated. In addition, by arranging the two actuators 4, 4' symmetrically with respect to the center axis of the spindle, the center of gravity of the device can be aligned with the center of the spindle 2, which is effective in suppressing vibrations caused by seek reaction force. It will be advantageous.

FIG. 4 is a diagram showing a third embodiment of the present invention.

In this embodiment, two linear type actuators 44' are arranged to face each other and move in opposite directions (when one actuator 4 seeks from the outer to the inner side, the other actuator 44' also moves from the outer side to the inner side). The seek reaction force is completely eliminated. Furthermore, by dividing the actuator into two actuators, it has the same effects as the rotary type, such as being advantageous for high-speed access. Note that even in a stacked type in which two actuators 4.4' are stacked one above the other as shown in Fig. 5, the same effect as shown in Fig. 4 can be obtained by moving both actuators 4.4' in opposite directions. You can get the following effect.

[Effects of the Invention] As described above, according to the present invention, it is possible to suppress the movement of the entire device due to the seek reaction force that impedes high-speed access. Furthermore, it is possible to realize a lighter actuator, which improves high speed and head positioning accuracy, and contributes to the realization of a large-capacity magnetic disk device with increased trunk density.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a first embodiment of the invention, FIG. 2 is a diagram showing a configuration example of the first embodiment of the invention, and FIG. 3 is a diagram showing a second embodiment of the invention. , FIG. 4 shows a third embodiment of the present invention, FIG. 5 shows a modification of the third embodiment of the invention, FIG. 6 shows a conventional magnetic disk device, and FIG. FIG. 7 is a block diagram showing a configuration including a conventional dual actuator circuit. In the figure, 1 is a magnetic disk, 2 is a spindle, 3 is a magnetic head, and 4.4' is an actuator.

Claims (1)

[Claims] 1. A plurality of magnetic disks (1) for recording information, a spindle (2) for rotating the magnetic disks (1), a plurality of magnetic heads (3) for reading and writing information; In a magnetic disk device comprising an actuator (4) for positioning a magnetic head (3), a housing (5) for holding a spindle (2) and an actuator (4), and a head positioning control circuit, the plurality of magnetic The head (3) is divided and mounted into two or an even number of actuators (4, 4'), and the seek reaction force is eliminated by always accessing the plurality of actuators (4, 4') almost simultaneously. A magnetic disk device characterized by: 2. The magnetic disk device according to claim 1, wherein two rotary actuators (4) are provided, and the two actuators (4, 4') have a structure that is almost mirror-symmetrical to each other, and the rotation for seek A magnetic disk device whose directions are opposite to each other. 3. The magnetic disk device according to claim 1, wherein two rotary actuators (4) are used, and the two actuators (4, 4') have substantially the same shape and are point symmetrical with respect to the spindle rotation center. A magnetic disk device installed at the location. 4. The magnetic disk device according to claim 1, wherein the magnetic head (3, 4') is mounted on two actuators (4, 4').
) is arranged on each side of a magnetic disk (1), and the head of each actuator (4, 4') has a recording area separated into an inner circumference and an outer circumference of the magnetic disk. 5. The magnetic disk device according to claim 1, wherein one magnetic head (1) is provided for each surface of the magnetic disk (1).
3), and a head arm (4a) corresponding to the magnetic head (3) is roughly divided into two actuators (4, 4'). 6. The magnetic disk device according to claim 1, wherein one set of external interface and overall control circuit is provided, and two sets of only head positioning control circuits are provided.