JPS6292191A - magnetic disk device - Google Patents

Abstract

PURPOSE:To prevent the positioning accuracy of a magnetic head from being affected by temperature changes by tilting the magnetic head in the same direction orthogonal to the head moving direction when a disc rotation shaft and a carriage support shaft reach the tilted state due to a gap caused by the temperature changes. CONSTITUTION:When a temperature rises, a gap is caused between an outer race of a bearing 8b and a bearing housing 7 by the difference of the thermal expansion coefficient between the outer race of the bearing 8b and the bearing housing 7 with respect to the part of a disc rotation shaft 6. With respect to the part of the support shaft 17, a gap is caused between the housing 20 and the inner circumferential face of a hole 21 of a carriage block 19. When the gap is caused in this way, the disc rotation shaft 6 and the support shaft 17 are both tilted in the direction of arrow B while the tilted direction is limited by the action of radial pre-load devices 12, 24 and the disc rotation shaft 6 is rotated without lateral deflection. Thus, the magnetic disc 1 and a head carriage 15 are tilted simultaneously in a direction not given effect on the positioning of the magnetic head 16 to keep the initial positioning accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic disk drive, and more particularly to a high-density, small-sized, large-capacity magnetic disk drive.

[Background of the Invention] In recent years, there has been a demand for higher recording densities in magnetic disk devices, and to this end, it is necessary to maintain high positioning accuracy of the magnetic head even when the environmental temperature of the device changes. It is essential to be present.

One of the magnetic disk drives that minimizes temperature change.
An example is shown in Japanese Patent Application Laid-Open No. 58-171767.

This device uses one of the spindle shafts that support the magnetic disk.
It consists of a stainless steel ring placed between the sleeve holder and the aluminum housing. However, because the coefficient of thermal expansion of the ring material and the coefficient of thermal expansion of the bearing material P+ are slightly different, changes in environmental temperature create a gap between the ring and the bearing, causing the spindle shaft to run out and rotate. As a result, a decrease in the positioning viscosity of the magnetic head was unavoidable.

[Purpose of the invention]

An object of the present invention is to provide a magnetic disk device in which the positioning viscosity of a magnetic head is substantially unaffected by temperature changes.

[Summary of the invention]

The present invention provides a means for applying a radial preload in a predetermined direction to a disk rotation shaft that supports and rotates a magnetic disk and a carriage support shaft that rotatably supports a magnetic head carriage. When the rotating shaft and the carriage supporting shaft are in a state where they can tilt, the disk rotating shaft and the carriage supporting shaft are perpendicular to the direction in which the magnetic head moves and tilt in the same direction. It is. The direction of inclination of the disk rotation axis and the key X/ridge support axis is 2 degrees above the magnetic head.
There is a direction C that does not affect the determining direction, does not change the relative inclination angle between the magnetic head and the magnetic disk, and does not affect the flying posture of the magnetic head.

[Embodiments of the invention]

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

In FIGS. 1 to 4, reference numeral 1 denotes a magnetic disk, which is fixed to a hub 3 with a clamp 4 in a stacked state with a spacer 2 interposed therebetween. The hub 3 is fixed to a disk rotating shaft 6, which is the rotating shaft of the motor 5. In particular, as shown in FIG. 1, the rotation @6 is supported at two upper and lower positions by bearings 8a and 8b built into a cylindrical bearing housing 7.

The bearing housing 7 is fixed to the base 10 by being shrink-fitted to the center of a substantially disc-shaped housing 11 . The magnetic disk 1 is rotated integrally with a hub 3 and the like by a motor 5. The vibration of the magnetic disk 1 during rotation is suppressed by applying a thrust preload to the bearings 8a and 8b by a coil spring 9.

The material used for the base 10 is aluminum, which has a light M and has good workability. The material of the housing 11 is aluminum to match the base 10. This prevents the bimetal effect from occurring between the base 10 and the housing 11, thereby reducing the influence on the magnetic head positioning accuracy.

The material of the bearing housing 7 is iron-based, which is the same as the material of the outer rings of the bearings 8a and 8b. The bearing housing 7 and the housing 11 have a symmetrical shape in the circumferential direction so as not to cause uneven thickness due to temperature changes, and are connected so as not to form a temperature bimetal.

Reference numeral 12 denotes a radial preload applying mechanism which is an important part of the present invention, and applies a radial preload to the outer ring of the lower bearing 8b in the direction shown by arrow B, which is perpendicular to the direction of movement of the magnetic head shown by arrow A in FIG. It has been given an F1 rating. This mechanism 12 has an annular groove 1 eccentrically formed on the inner peripheral surface of the bearing housing 7.
It has a structure in which an O-ring 14 is fitted into the inside of the holder 3.

A magnetic head carriage 15 supports a magnetic head 16 at its tip and is fixed to a carriage support shaft 17. As shown in FIG. 2, the support shaft 17 is attached to a carriage block 19 with its upper and lower ends supported by bearings 18a and 18b, and is parallel to the disk rotation @6. The upper bearing 18a is heat-bonded to one carriage block at a high temperature so that no adverse effects occur within the operating temperature range of the assembly. A housing 20 made of a material having the same coefficient of thermal expansion as the outer ring is fixed to the outer side of the outer ring of the lower bearing 18b. This housing 20 is fitted and fixed within a hole 21 of the ridge block 19. By providing the housing 20, the rigidity of the bearing 18b is increased and the vibration characteristics are improved.

At the other end of the head blade ridge 15, an actuator 22 using a voice coil motor is installed, as shown in Figure M3. 23 is a voice.

When the actuator 22 is activated, the head ridge 15
rotates together with the support shaft 17, and the magnetic head 16 is moved and positioned in the direction of the arrow Δ.

In FIG. 2, reference numeral 24 represents a radial preload applying mechanism, which is a main part of the present invention, and applies a radial preload "2" to the housing 20 in the same direction of arrow 8 as described above.

This mechanism 20 has a 4'4 construction in which a compression coil spring 26 is housed in a horizontal hole 25 of one carriage block and is prevented from being removed with a set screw 27.

When the temperature rises during operation of the device, a gap is created between the outer ring of the bearing 8b and the bearing housing 7 due to the difference in thermal expansion coefficient between the outer ring of the bearing 8b and the bearing housing 7 in the portion of the disk rotating shaft 6. .

As for the support shaft 17, a gap is created between the housing 20 and the inner peripheral surface of the hole 21 of the four-legged block 19. If a gap occurs in this way, the radial preload mechanism 12
．． Due to the action of 24, the disk rotation shaft 6 and support @17
Both are inclined in the direction of arrow B with a limited direction of inclination. The disk rotation shaft 6 rotates in this state without any shaft vibration. As a result, the magnetic disk 1 and head carriage 15 are
At the same time, the magnetic head 16 is tilted in a direction that does not affect the positioning of the magnetic head 16, so that even if the temperature rises, the positioning accuracy of the magnetic head does not decrease and the initial positioning accuracy is maintained.

Also, since the direction of inclination 1 of the magnetic disk 1 and the head 1 shaft 15 is in the direction of arrow B, there is no relative inclination angle between the bta disk 1 and the magnetic head 16 due to (around!:1), and the magnetic head 1 The levitation position does not change.

Therefore, according to the magnetic disk device having the above-mentioned configuration, the positioning accuracy of the magnetic head b is not affected by temperature changes;
461.13 determination margin can be improved to about 1.5 μm.

In addition, regarding the disk rotating shaft 6, radial preload may be applied to the upper bearing 8a instead of the lower bearing 8b. However, in this case, the direction in which the radial preload is applied is opposite to the direction in which the radial preload is applied to the lower bearing 8b.

Further, in FIG. 1, 28 is a magnetic fluid seal.

Since the bearing housing 7 is a magnetic material, leakage magnetic flux from the magnet of the magnetic fluid seal 28 is shielded by the bearing housing 7 and does not reach the magnetic head 16 11'.

Further, as shown in FIG. 3, the disk rotating ring 6 is located at a position offset downward in the figure by a dimension a (for example, about 4 IwR) from the center line CL of the good hand force direction of the device whose external dimensions are specified. It is set up.

This arrangement firstly reduces the access time of the magnetic head. That is, the above arrangement increases the space for arranging the actuators, and the nine-person actuator 22 with a large output is incorporated therein.

Second, it is possible to increase the capacity. When the number of magnetic disks is increased to increase capacity, the number of magnetic heads increases accordingly, and the weight of the magnetic head carriage increases. The magnetic head carriage and voice coil must be balanced around the support shaft.

There is a method of dealing with the increase in the number of magnetic heads (1-Year Ridge) by using a brass cap for the bobbin material of the voice coil, but this method also has its limits as the number of magnetic heads increases.

As the disk rotating shaft 6 is disposed as shown in 1, the support shaft 17 is also disposed at a lower position in the figure than the normal position as shown in FIG. This makes it possible to increase the length L+ of the arm on the side of the voice coil 23 from the support shaft 17, and in this embodiment, the balance between the magnetic head carriage 15 and the voice coil 23 is maintained by this method. Magnetic head key again!・Ridge 15 arm length L2
The binding is shorter than the conventional one, about 60#.

Third vf! dust? The structure is such that the process can be carried out efficiently. As the magnetic disk 1 rotates at high speed, the air on the recording surface of the magnetic disk 1 blows out to the outer periphery, and in the center of the negative pressure, dust passes through the machine side 30 as shown in FIG. Air flows in from the top. The F3G mechanism 30 includes a plate-shaped filter 33 supported by a support plate 31F and disposed between it and the top cover 32. By arranging the disk rotation shaft 6 in a biased manner as described above, the same space can be used to provide air inflow side to the PARM 430.
An air dam 34 protruding from the base 10 is formed along the outer periphery of the magnetic disk 1. The air flowing in the direction of arrow C in FIG. 3 once enters the columnar space 35 between the air 1 & 234 and the rising side wall 10a of the base 10, and flows into the passage mechanism 30 through this space. At this time, an air flow flowing in the disk circumferential direction due to the rotation of the magnetic disk 1 flows into the columnar space 35, so the pressure in the columnar space 35 increases, and the difference between the inflow side and the outflow side with respect to the feeding mechanism 30 increases. The pressure is higher than before, and the amount of air passing through the filter structure 30 per unit time increases. As a result, foreign particles in the air circulating inside the device are efficiently captured by the filter 31, and the air inside the device is quickly and completely purified.

Note that the plate-shaped filter 33 is arranged diagonally as shown in FIG. 5, and has a large area that functions as a filter despite the narrow space.

If the fibers of the magnetic filter 33 are damaged, foreign particles may fall from the filter 33, but these foreign particles are prevented from falling onto the support plate 31 and being attached to the magnetic disk 1. In addition, the top cover 32 and the support plate 31
has sufficient rigidity, and stress is not generated in the filter 33 even by a photographing impact.

〔Effect of the invention〕

According to the present invention, the disk rotation shaft that supports and rotates the magnetic disk and the one-way support shaft that supports the magnetic head carriage can be prevented from being tilted due to temperature changes and the gap between them. The magnetic head moves when
Since the magnetic head is tilted in the same direction perpendicular to the direction of the magnetic head, the magnetic head positioning accuracy is virtually unaffected by temperature changes, and the magnetic head positioning margin is improved to, for example, about 1.5 μm. This has the effect of enabling high-density recording.

[Brief explanation of drawings]

1 and 2 are enlarged cross-sectional views showing the configuration near the disk rotation axis and carriage support shaft of a magnetic disk device according to the present invention, respectively, and FIG. 3 is an enlarged sectional view of an embodiment of the magnetic disk device according to the present invention. FIG. 4 is a cross-sectional view taken along line rV-IV in FIG. 3, and FIG. 5 is a partially cutaway plan view of the top cover. FIG. FIG. 3 is a cross-sectional view taken along the line. DESCRIPTION OF SYMBOLS 1... Magnetic disk, 5... Motor, 6... Disk rotating shaft, 7... Bearing housing, 8a, 8b...
・Bearing 10...Base, 12.24...Radial preload applying mechanism, 13...Groove, 14...O ring, 15
...Magnetic head carriage, 16...Magnetic head,
17... Carriage support shaft, 18a, 18b... Bearing, 19... Carriage block, 20... Housing, 21... Hole, 22... Actuator, 23
...Voice coil, 25...Horizontal hole, 26...Compression coil spring, 27...Set screw. Representative Patent Attorney Katsoo Ogawa Figure 4/Tsu

Claims (1)

[Claims] a magnetic head carriage having a magnetic disk, a disk rotation shaft that supports and rotates the magnetic disk, and a magnetic head that faces the magnetic disk; and a magnetic head carriage arranged parallel to the disk rotation axis. In a magnetic disk drive having a carriage support shaft that supports a carriage, and an actuator that rotates the magnetic head carriage about the carriage support shaft to move and position the magnetic head, the disk rotation shaft and the carriage are provided. Each of the support shafts is provided with means for applying a radial preload in a direction perpendicular to the direction in which the magnetic head moves, and when the disk rotation shaft and the carriage support shaft are likely to tilt due to a temperature change. A magnetic disk drive characterized in that the radial preload applying means is configured to tilt both the disk rotating shaft and the carriage support shaft in the same direction perpendicular to the direction in which the magnetic head moves.