JPH01179284A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To suppress thermal off-track and to realize the high density of a track by providing a spacer mode of shape memory alloy among the axial plane of the inner ring or outer ring of a reference bearing, a shaft corresponding with the plane, and a rotary cylinder. CONSTITUTION:The spacer 16 made of the shape memory alloy is arranged between the axial plane of the inner ring of the reference bearing 2 at a fixed side out of the bearings which support the rotary cylinder 4 and the reference plane of a fixed shaft 1. By constituting a device in such way, the plane thickness of the spacer 16 made of the shape memory alloy can be changed reversibly according to temperature change in a head disk assembly (HDA). Thereby, the inner diameter of the reference bearing 2 and a pre-load bearing 3 and the fixed shaft 1 are fitted slidably as applying correction so as to keep the relative position of a magnetic head with a magnetic disk corresponding to the temperature change in the HDA. Therefore, it is possible to suppress the thermal off-track due to the temperature in the HDA, and to realize the high density of the track in a magnetic disk device.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention is directed to a head-disk assembly (hereinafter referred to as HDA) equipped with an oscillating actuator configured to reduce off-track caused by temperature changes in a head-disk assembly (hereinafter referred to as HDA). Related to magnetic disk devices.

(Prior art and problems to be solved by the invention) There are two construction methods for a swing type actuator. The first construction method is an outer ring rotating type as shown in Fig. 5, and the second construction method is is the inner ring rotating type shown in FIG. Further, FIGS. 7 and 8 are diagrams for explaining thermal off-track.

In these figures, the iFi axis (fixed or rotating axis), 2
is a reference bearing, 3 is a preload bearing, 4 is a rotary cylinder,
5 is a helad arm, 6 is a clamp ring, 7#'i disk clamp, 8 is a moving coil, 9 is a magnet, 10 is a yoke, 11 is a pace, 12 is a support plate, 13 is a preload spring, 14 is a magnetic head, 15 is a magnetic disk.

In the configuration of the outer ring rotating type shown in FIG. 5, shaft 1 is a non-rotating shaft,
In the inner ring rotating type shown in FIG. 6, the shaft 1 is a rotating shaft.

In other words, as a construction method, there is a difference between the rotation of the outer ring and the rotation of the inner ring of the bearing. The configuration of the outer ring rotating type shown in FIG. 5 is such that the inner rings of a reference bearing 2 and a preload bearing 3 are fitted onto a fixed shaft 1, the fixed shaft 1 is supported in a non-rotating state, and each of the reference bearing 2 and preload bearing 3 is supported in a non-rotating state. The outer ring of the rotary cylinder 4 is fitted into the rotary cylinder 4 and rotated. In the rotary cylinder 4, spacing doors 5 and clamp rings 6 are alternately stacked and integrated by a disk clamp.

A magnetic circuit consisting of a magnet 9 and a yoke 10 corresponds to the moving coil 8 that drives this oscillating body.
1 and a support plate 12. In order to improve the positioning accuracy of the actuator, a preload is applied to the preload bearing 3 by a preload spring 13. - In the configuration of the inner ring rotating type shown in Fig. 6, the rotating shaft 1 fitted into the inner rings of the reference bearing 2 and the preload bearing 3 rotates, and the outer rings of the reference bearing 2 and the preload bearing 3 do not rotate. It is supported by the pace 11 and the support plate 12.

In this oscillating type actuator, the rotary cylinder 4, head arm 5, clamp ring 6, and disk clanger are integrated and driven by the moving coil 8, so this oscillating body prevents thermal deformation of the HDA. If a relative positional shift occurs in the direction of the rotating axis of the magnetic disk rotating body with respect to the reference, the magnetic head 14 supported by the head arm 5 and the magnetic disk 1 will shift as shown in FIG.
As a result, as shown in FIG. 8, a positional deviation occurs between the magnetic disk rotating body A and the floating head B, and for example, the relatively floating head B moves toward the arrow Y. If the position shifts in the direction, one magnetic hect 14
to the outside of the magnetic disk 15 and the other magnetic head 1
4 is shifted to the inside of the magnetic disk 15.

Therefore, a phenomenon in which the magnetic heads are misaligned with each other, that is, a thermal off-track due to a temperature change of the HDA occurs, making recording and reproduction impossible.

Measures to reduce this thermal off-track were taken by changing the design of the mechanism configuration and changing the materials of the mechanism components.
These measures have limitations, and there are limits to achieving high track density in magnetic disk drives.

(Objective of the Invention) An object of the present invention is to provide a magnetic disk drive equipped with an oscillating actuator configured to suppress thermal off-track generated in response to temperature changes in an HDA.

(Means for solving the problems) The present invention has been proposed to achieve the above objects, and
This is particularly effective for floating head mechanisms supported by a Whitney-shaped head support mechanism.

In other words, in the previously used winchester type gimbal support system, the normal setting posture was that the magnetic disk medium and the load beam were parallel, so the magnetic disk rotating body and the actuator system were aligned in the direction of the rotation axis. Even if the position shifted, the amount of off-track caused by it was minute.

On the other hand, the Whitney type, which has become widely used in recent years, has a set angle between the magnetic disk medium and the load beam at the 9th point, so that if a misalignment occurs in the direction of the rotation axis, the head beam is supported by the same head bar. The upper head and the down head generate positional deviations in opposite directions. For this reason, the amount of off-track becomes larger compared to the conventional wintier cymbal.

In contrast, the present invention uses a shape memory alloy as a spacer, takes advantage of its reversible shape change in the thickness direction, and appropriately sets the transformation temperature to integrate the head arm, crank ring, and disk crank. The rotary cylinder is moved in the direction of the rotation axis of the magnetic disk rotor with respect to the reference of the actuator system, and is configured to correct off-track caused by thermal changes in the magnetic disk rotor and the actuator system.

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

Note that the embodiments are merely illustrative, and it goes without saying that various changes and improvements can be made without departing from the spirit of the present invention.

Fig. 1 and Fig. 2 respectively show an embodiment of the present invention, in which an outer ring rotating actuator is provided with a spacer assembly made of a shape memory alloy. Further, FIGS. 3 and 4 are diagrams showing other embodiments of the present invention, in which a spacer made of a shape memory alloy is provided in an actuator of an inner ring rotation type. Note 1. In the following explanation,
Components with the same reference numerals as those in the conventional example shown in FIGS. 5 and 6 have the same functions as those in the conventional example, so a description thereof will be omitted. Example t will be described below with reference to each figure. FIG. 1 shows an embodiment in which a spacer 16 made of a shape memory alloy is disposed between the axial surface of the inner ring of the fixed-side reference bearing 2 of the bearings that support the rotary cylinder 4 and the reference surface of the fixed shaft 10. Additionally, the thickness of the shape memory alloy spacer 16 changes reversibly as the temperature of the HDA changes. For this reason, in the configuration shown in FIG. 1, the inner diameters of the reference bearing 2 and preload bearing 3 and the fixed shaft 1 are corrected to maintain the normal relative position between the magnetic head and the magnetic disk in response to temperature changes in the HDA. They fit together so that they can slide from the bend.

Figure 2 shows the fixed shaft 10 reference surface and the axial surface of the inner ring of the fixed reference bearing 2 being joined, and a spacer made of a shape memory alloy being placed between the axial surface of the outer ring of the reference bearing 2 and the rotary cylinder 4. This is an example in which 16 are arranged. In this ninth step, the outer diameter of the reference bearing 2, the inner diameter of the rotary cylinder 4, the inner diameter of the preload bearing 3, and the fixed shaft 1 are fitted to be able to slide in response to temperature changes. Figure 4 shows another embodiment applied to an actuator with a rotary inner ring. An embodiment in which a spacer 16 made of a shape memory alloy is provided between the reference surface of the reference bearing 2 and the axial surface of the inner ring of the fixed-side reference bearing 2 fitted to the base 11 of the stator section is shown.

In this embodiment, Fl, the inner diameter of the preload bearing 30, and the rotor shaft 1 are slidably fitted in response to changes in the temperature of the HDA. In Figure 4, the reference surface of the rotor shaft 1 is in contact with the axial surface of the inner ring of the fixed-side reference bearing 2, and there is a space made of a shape memory alloy between the axial surface of the outer ring of the bearing and the pace 11 of the stator section. In this embodiment as well, the inner diameter of the preload bearing 3 and the rotor shaft 1 are slidably fitted in response to changes in the temperature of the HDA.

(Effects of the Invention) As explained above, the axial surfaces of the inner and outer rings of the reference bearing, which serve as the reference for the relative position between the magnetic disk rotating body and the actuator, and the axial surfaces thereof.

A spacer made of a shape memory alloy whose plate thickness is memorized so that it changes reversibly in response to temperature changes within the HDA is placed between the corresponding shaft and rotary cylinder7.
From I-, the effect is that even if a positional shift occurs between the magnetic disk rotating body and the actuator (C5 magnetic disk rotating body in the rotational axis direction) due to temperature changes in the HDA, the temperature of the shape memory alloy spacer and the HHDA will change. It functions to correct the positional deviation according to the change, and it is possible to suppress off-track caused by the positional deviation, and it is possible to realize a high track density of the magnetic disk device.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are diagrams showing an embodiment of the present invention, respectively, and FIGS. 3 and 4 are diagrams showing an embodiment in which a spacer made of a shape memory alloy is provided on an outer ring rotating type actuator. 5 shows another embodiment of the present invention, in which a spacer made of a shape memory alloy is provided on the actuator of the inner ring rotating type, and FIG. 5 shows a conventional outer ring rotating type actuator. FIG. 6 is an explanatory diagram of an actuator, FIG. 6 is an explanatory diagram of a conventional inner ring type actuator, and FIGS. 7 and 8 are diagrams illustrating misalignment between a magnetic disk rotating body and a floating head mechanism. 1... Shaft (fixed or rotating shaft), 2... Reference bearing, 3
...Preload bearing, 4°...Rotary cylinder, 5.
...Head arm, 6...Flanging, 7...
Disc clamp, 8...Moving coil, 9...
・McNett, 10...York, 11...Pace,
12... Support plate, 13... Preload spring, 14... Magnetic head, 15... Magnetic disk, 16... Spacer made of shape memory alloy. Applicant Nippon Telegraph and Telephone Corporation - Figure 1 2J Figure 3 Figure 4 Figure 5-11 1Q 9 Figure 6 x Figure 7 Figure 8

Claims (5)

[Claims] (1) Temperature changes within the head/disk assembly can be prevented between the axial surface of the inner ring or outer ring of the reference bearing, which serves as a reference for the relative position of the magnetic disk rotating body and the actuator, and the shaft corresponding to the axial surface and the rotary cylinder. A magnetic disk device characterized in that a spacer made of a shape memory alloy whose plate thickness changes reversibly correspondingly is installed. (2) In an actuator with a rotating outer ring, among the bearings that swingably support the rotary cylinder on a fixed shaft,
2. The magnetic disk device according to claim 1, wherein a shape memory alloy is disposed between the axial surface of the inner ring of the reference bearing, which serves as a reference when stacking the head bars, and the reference surface of the fixed shaft. (3) In an actuator with a rotating outer ring, the reference surface of the fixed shaft is joined to the axial surface of the inner ring of the reference bearing, which serves as a reference when stacking the head bar, and the axial surface of the outer ring of the reference bearing is connected to the rotary cylinder. 2. The magnetic disk device according to claim 1, wherein a shape memory alloy is disposed in the magnetic disk device. (4) Between the reference surface of the rotor shaft of a rotor shaft structure in which the shaft is swingably supported in an actuator with a rotating inner ring and the axial surface of the inner ring of the reference bearing of the stator section, which serves as a reference when stacking head bars. 2. The magnetic disk device according to claim 1, wherein a shape memory alloy is disposed in the magnetic disk device. (5) In an actuator with a rotating inner ring, the reference surface of the rotor shaft that can freely swing is joined to the axial surface of the inner ring of the reference bearing that serves as a reference when stacking the head bar, and the axial surface of the outer ring of the reference bearing and the stator section 2. The magnetic disk device according to claim 1, further comprising a shape memory alloy disposed between the magnetic disk device and the magnetic disk device.