JPH02263369A - Data head arm and head positioning device for magnetic disk device - Google Patents

Abstract

PURPOSE:To shorten the access time to improve the throughput by building minute displacement generating elements, which mechanically deform data head arms independently of one another, in individual data head arms supporting data heads. CONSTITUTION:A head actuator consists of a servo arm 2 provided with one servo head 1 only for seek and tracking, a carriage 5 related to the actuator by which plural data heads 3a and 3b and data arms 4a and 4b provided with piezoelectric elements 24a and 24b related to minute displacement generating elements are moved as one body, and a VCM 6 which can move them. At intervals of a certain time or at the time of the occurrence of off-track of data heads 3a and 3b, data head arms 4a and 4b in which minute displacement generating elements are built are mechanically deformed independently of each other to correct off-track of the oscillation component of low frequency including heat. Thus, the access time is shortened to improve the throughput.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data head arm and a head positioning device for a magnetic disk drive, and in particular, to reduce off-track in a magnetic disk drive on a remote island with a high track of 1500 TPI or more. The present invention also relates to a data head arm and a head positioning device for a magnetic disk device suitable for enabling high-speed access and improving throughput.

[Conventional technology]

The conventional magnetic disk head positioning device is U
As described in S P , No. 4072990.

Seek control used a servo surface servo method, and tracking used a combination of servo surface servo method and data surface servo method.

Its configuration includes a plurality of magnetic disks mounted for rotation on a driving spindle, a plurality of recording/reproducing data heads corresponding to a plurality of data surfaces, and each data track containing a data sector and position information. The servo sectors are arranged alternately, the servo heads are interlocked with the movement of the data head and are associated with the servo surfaces on the two disks, and the continuous data track position information is preliminarily written on the servo surfaces. given by the recorded servo tracks.

The operation is such that a signal generated from the servo surface moves the data head during track access operation. control Flj,
The signal generated from the servo sector on the data surface controls the positioning of the data head during track following operation, and furthermore, the high frequency component of the signal derived from the servo surface is added to the signal derived from the servo sector during track following. ing.

[Problem to be solved by the invention]

In the above conventional technology, when an arbitrary data head among a plurality of data heads records or reproduces information, if an off-track occurs, the data head writes a sector-by-sector data on the corresponding magnetic disk medium surface in advance. It moves to reduce off-track according to the servo information including the written position information.

Therefore, after the servo head reaches a predetermined track, the data head, which is moving together with the servo head,
For example, when a magnetic disk medium rotates at 3,600 rpm, the time required to pass through at least one sector is required before recording and playback becomes possible.
Assuming that it is divided into sectors, the average access time (not including rotational waiting time) is approximately If it is 12m5.

The magnitude of 0.52 m s reaches a magnitude of 4.3%.

Therefore, the above-mentioned conventional technology does not take into account the length of waiting time until the data head, which moves integrally with the servo head, becomes capable of recording and reproducing after the servo head reaches a predetermined track. , there was a problem in that the throughput decreased further.

The present invention was made in order to solve the problems of the prior art described above, and when the data head is off-track, the data head arms are mechanically deformed independently to reduce the amount of heat including heat. It operates to correct the off-track of the vibration component of the frequency, and for subsequent access, after the servo head reaches the predetermined track, only the off-track of the vibration component of the high frequency is corrected using the position information of the servo surface. It is an object of the present invention to provide a data head arm and a head positioning device for a magnetic disk device that can be operated to reduce access time and improve throughput.

[Means to solve the problem]

In order to achieve the above object, the configuration of a data head arm of a magnetic disk device according to the present invention includes an actuator that includes one servo head dedicated to seek and tracking and a plurality of data heads and moves together; One surface is a servo surface corresponding to a servo head, and the other surface is a data surface in which each track has data selectors and servo sectors containing position information arranged alternately, and magnetic disk media rotation. In a magnetic disk device consisting of a spindle motor for use with a storage device, a recording six-component circuit, two positioning control circuits, and a spindle motor drive circuit, each data head arm that supports a data head is mechanically independently connected to the data head arm. It incorporates a minute displacement generating element that can be deformed.

In addition, in order to achieve the above object, the configuration of the head positioning device of the magnetic disk drive according to the present invention is such that the above-mentioned minute displacement generating element The data head arms that incorporate the After that, a control circuit is provided which operates to correct only the off-track of the high frequency vibration component using the position information of the servo surface.

[Effect]

Head of such a magnetic disk device! The device determines i' by mechanically deforming multiple data head arms independently at regular intervals or when the data head is off-track, and detecting low-frequency vibration components including heat. For subsequent access, by operating to fix the off-track of
After the servo head reaches a predetermined track, the servo head uses position information on the servo surface to operate to correct only the off-track of high-frequency vibration components, reducing access time and improving throughput.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 8.

FIG. 1 is a control block diagram of a head positioning device for a magnetic disk device according to an embodiment of the present invention, and FIG.
A perspective view of a data head arm equipped with a minute displacement generating element of the device shown in the figure and a head positioning mechanism using the data head arm. FIG. 4, a diagram showing the relationship between displacement and generated force when voltage is applied, shows the pressure i? having the characteristics shown in FIG. FIG. 5 is a side view of FIG. 4. As shown in FIG. 1, the head actuator has one servo head dedicated to seeking and tracking. 1, a plurality of data heads 3a, 3b, and piezoelectric elements 24a, 24b related to minute displacement generating elements.
The data arms 4a and 4b each include a carriage 5 that is an actuator that moves together, and a VCM 6 that moves them.

The magnetic disk medium 7 consists of a plurality of magnetic disk media, one surface of which is a dedicated servo surface 8 for seeking and track king, and all other surfaces are data surfaces 9a and 9b provided with positional information. It is attached to a spindle motor 10 for rotating the medium, and is rotated at a constant number of rotations per unit time by a spindle motor drive circuit 11.

When a target position command xo is issued from the host device 12 to the servo head 1, seek is first performed using speed control.
Trackking is performed by position control after the target position [xo] has been sufficiently approached. This part is the same as the conventional method. That is, the procedure for seeking with speed control is to first send a position signal from the servo head 1 located on an arbitrary track to the servo head 1 through the servo amplifier 13 and the position detection circuit 14.
Obtain the current position Xs. Xs and x in comparison circuit 15.

When the difference ΔXs is calculated and transmitted to the speed function generator 16, the speed function generator 16 uses the speed pattern table 17 to issue a target speed command Vo. On the other hand, X passes through the speed calculation circuit 18 and is converted into the current speed Vs of the servo head 1. The comparator circuit 19 calculates the difference ΔVs between Vs and Vo, and the amplifier 21 is used to supply the current required for ΔVs to the VCM 6.

Next, what is the procedure for tracking with 1-position control?

After the servo head 1 approaches the target position xo sufficiently, the switch 20 is switched using the switch control circuit 22, and the position control circuit 23 is transferred to the servo surface servo type position control circuit 23 to perform position control.

The head positioning device of this embodiment moves the individual data head arms 4a and 4b equipped with piezoelectric elements 24a and 24b when off-track of the data head occurs even though the servo head 1 is at the target position Mxo. They are designed to be mechanically deformed independently so as to follow the data track.

First, when the servo head 1 reaches the target position tmxo, the switch 27 is turned on using the switch control European circuit 25. The position signal from the data head 3a or 3b is passed through the amplifier 29 and the position detection circuit 30 to the data head 1.
Obtain the current position f14x-.

The comparator circuit 31 calculates the difference ΔX- between X- and xo, and calculates Δχ
- The piezoelectric element 24a, which is a minute displacement generating element, uses the amplifier 34 or 35 to supply the necessary voltage.

Add to 24b. The switch control circuit 32 is the comparison circuit 31
The output of &il? Switching is controlled to eliminate off-track of all data heads. Further, the timer 26 plays a role of performing the above operation at regular intervals.

FIG. 2 is a perspective view showing an embodiment of a swing type data head arm equipped with a minute displacement generating element such as a piezoelectric element.

The data head 3a floats above a data surface 9a provided with track information of the rotating magnetic disk medium 7. Terminal 36a of piezoelectric cord 24a.

When a voltage is applied to 36b, it expands and contracts in the Z direction, and the data head 3a can be controlled in the Y direction of tracking.

Figure 3 shows the displacement ΔZ of the piezoelectric element that can be attached to the oscillating data head arm when a driving voltage E=12V is applied.
This represents the relationship between F and the Z-direction generated force F.

The data head arm 4a of this embodiment shown in FIG. 4 passes through the center of the width g in the Y direction of the piezoelectric element 24a having the characteristics shown in FIG. It is attached to a notch in the head arm 4a.

The track density in the radial direction of the magnetic disk medium 7 is 150
When the density is higher than 0 TPI, the width of one track is 16
．． 6 piezoelectric element 24a, which is 9 μm or less, and the positioning accuracy of the mechanical system, excluding recording and playback, must be approximately 2 μm or less in the Y direction even when disturbances such as vibration, shock, temperature, humidity, and atmospheric pressure changes are applied. The track width direction change ΔY of the data head 3a due to the Z direction change ΔZ is expressed as Δy=axΔθ. Here, Δθ is an angle at which the piezoelectric element 24a rotates around the end on the data head 3a side among both ends in the Z direction. In addition, Ω is the piezoelectric element 24
This is the distance from the end of a to the data head 3a. Now let's say Ω = 40 m.

If ΔY=2 μm, Δθ is Δθ=2X10″″’am/40m = 5 X 10-’rad becomes.

The amount of change ΔZ required in the Z direction of the piezoelectric element 24a is:
If the distance from the Z axis to the vicinity of the notch end is m = 10m, ΔZ = mXΔθ = 10mX 5 X 10-'rad = 5X10-4
The diameter is 0.5 μm.

From Figure 3, when ΔZ = 0.5 μm, the Z of the piezoelectric element
The generated force in the direction is F = O,, 35 kg f.

Using this generated force F, the dimensions d, e, thickness t, material, etc. of the notched portion of the data head arm 4a may be determined so as to generate the inclination angle Δθ.

FIG. 5 is a side view of FIG. 4, showing the data head arm 4a having a thickness of t.

The access time Ta is the sum of the seek time T1 by the servo surface servo control method and the time T2 until recording and reproduction becomes possible by the combined method of the servo surface servo control method and the data surface servo control method.

Ta=T1+T2 It can be expressed as

This example is described in USP 407299 of the prior art described above.
When compared with No. 0, both T1s have the same size. However, regarding the time T2 until recording and playback becomes possible, USP No. 4072990 attempts to eliminate off-track every time it is accessed.
In the case of one track with 32 sectors, a time of T2=0.52m5X (one sector or more) is required.

On the other hand, in this embodiment, if the off-track of low-frequency vibration components including heat is corrected, the data head arm 4a mechanically maintains the amount of deformation. After reaching , using the position information of the servo surface.

It operates to correct only the off-track of high-frequency vibration components, thereby reducing the magnitude of T2.

According to this embodiment, in a head positioning device of a magnetic disk drive, a plurality of data head arms are mechanically deformed independently at regular intervals or when a data head is off track. , for subsequent access by operating to correct off-track of low-frequency vibrational components, including heat.
After the servo head reaches a predetermined track, the servo head uses position information on the servo surface to operate to correct only the off-track of high-frequency vibration components, which has the effect of reducing access time and improving throughput.

Next, FIG. 6 is a front view of a data head arm of a magnetic disk device according to another embodiment of the present invention, and FIG.
8 is a front view showing a modification of the data head arm in FIG.
Components with the same reference numerals as those in FIG. 4 are the same parts as in the previous embodiment, so a description thereof will be omitted.

The data head arm shown in FIGS. 6 and 7 is of a separate configuration. 104a and 204a are the separated data head arms, 124a and 124b are piezoelectric elements related to minute displacement generating elements, and 136a.

136b is a terminal of the piezoelectric element 124a, and 136c.

136d is a terminal of the piezoelectric element 124b.

In this embodiment, by applying voltages in opposite directions to the piezoelectric elements 124a and 124b, a Y-direction displacement ΔY of the data head 38 is obtained, as shown in FIG.

According to this embodiment, the same effects as described in the previous embodiment can be expected.

〔Effect of the invention〕

As described in detail above, according to the present invention, when the data head is off-track, the data head arms are mechanically deformed independently to eliminate low frequency vibration components including heat. The servo head is operated to correct the off-track, and for subsequent access, after the servo head reaches a predetermined track, the servo head is operated to correct only the off-track of the high frequency vibration component using the position information of the servo surface. Accordingly, it is possible to provide a data head arm and a head positioning device for a magnetic disk device that can reduce access time and improve throughput.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a control block diagram of a head positioning device for a magnetic disk device according to an embodiment of the present invention. Fig. 2 is a perspective view of a data head arm equipped with a minute displacement generating element of the device shown in Fig. 1 and a head positioning machine using the data head arm, and Fig. 3 is a perspective view of a head positioning machine using the data head arm. is a diagram showing the relationship between the displacement and generated force of a possible piezoelectric element when a driving voltage is applied; FIG. 4 is an explanatory diagram of a modified data head arm equipped with a piezoelectric element having the characteristics shown in FIG. 3; Figure 5 is a side view of Figure 4 and numbered 6. FIG. 7 is a front view of a data head arm of a magnetic disk device according to another embodiment of the present invention, FIG. 7 is a sectional view taken along the line A-A in FIG. 6, and FIG. It is a front view showing deformation. 1... Servo head, 2... Servo arm, 3a. 3b--data head, 4a, 4b, 104a. 104b...Data head arm, carriage, 7...Magnetic disk medium, 8...Servo surface, 9a
. 9b...Data surface, 10...Spindle motor, 1
1... Spindle motor drive circuit, 14.30...
Position detection circuit, 23...Position control circuit, 24a, 24
b. 124a, 124b - piezoelectric element. Leather design

Claims (1)

[Claims] 1. An actuator that is equipped with one servo head dedicated to seek and tracking and a plurality of data heads and moves integrally; one surface is a servo surface corresponding to the servo head, and the other A plurality of magnetic disk media, each track of which is a data surface in which data sectors and servo sectors containing positional information are arranged alternately, a spindle motor for rotating the magnetic disk media, a recording/reproducing circuit, a positioning control circuit, and A magnetic disk drive comprising: a spindle motor drive circuit; and a magnetic disk device comprising: a spindle motor drive circuit; Data head arm of a magnetic disk device. 2. At regular intervals or when the data head is off-track, the data head arms according to claim 1 are mechanically deformed independently to turn off low frequency vibration components including heat. Control that operates to correct the track, and for subsequent accesses, after the servo head reaches a predetermined track, uses the position information of the servo surface to operate to correct only the off-track of the high frequency vibration component. A head positioning device for a magnetic disk device, comprising a circuit.