JPS605467A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To improve the revolving accuracy of a magnetic disk device and the positioning accuracy of a magnetic head, by providing a vibration damping controller at the end of a shaft in order to reduce the deflection of the shaft due to the axial resonance in a real working state, and the deflection of shaft due to the vibration transmitted to the shaft from a bearing. CONSTITUTION:A magnetic matter 13 provided at the end part of a main shaft is set opposite to a permanent magnet 12 provided at the still side. Then the bearing rigidity is increased in both thrust and axial directions by making use of the magnetic attraction force (restoring force) generated between the matter 13 and the magnet 12. Thus the vibrations of a shaft can be reduced. That is, said attraction power prevents the eccentricity of a main shaft 1 in both trust and axial directions against a shaft vibration mode (bend deformation mode of the shaft itself) of the shaft 1 generated in the operation state of a real device and the deflection (rigit material mode) of the shaft 1 due to the oscillations transmitted to the shaft 1 from ball bearings 2 and 3. Thus it is possible to reduce various vibration amplitudes produced with displacement of shaft down to the response of a low amplitude.

Description

DETAILED DESCRIPTION OF THE INVENTION [First Field of the Invention] The present invention relates to a magnetic disk device in which a rotating magnetic disk and a main shaft to which the magnetic disk is fixed are supported by a rolling bearing disposed on a base. It is.

[Background of the invention]

FIG. 1 shows a complete cross-section of the main parts of a conventional magnetic disk device.

The main rollers are rotatably supported on a base 4 by υ bearings 2 and 3. A knob 5 is fixed to this main shaft 1, and a large number of magnetic disks 6 are stacked on this knob 5 with a number of running distances Fi. A collar 7 is installed between the slip bearings 2 and 3 to maintain a constant spacing between the bearings in the axial direction.

A pulley 8 is fastened to the lower end of the main shaft 1 by bolts 9.

By tightening this pulley 8, the rolling shaft 93 tit
.

The coil spring 1 ( ) disposed inside the base 4 preloads it in the axial direction.

As mentioned above, (the main shaft lid of the magnetic disk drive made from '1~, the bell attached to the pulley 8) is rotated by the drive YJ, etc., such as the motor connected by the
A magnetic disk 6 is driven by a magnetic head (not shown).
↑) 'ntd read or disk 6
Information to -1 included, h++ payment will be made. Therefore, the rotating angle of the main Tsukuda 1 is greatly influenced by the 6-degree head position (16 degrees).In recent years, with the trend towards larger capacity magnetic disks, the rotation angle of the main Tsukuda 1 is on the order of submicrons. It's been requested.

Under these circumstances, there is a strong desire to avoid resonance in the spindle system during actual operation and to improve the dynamic rotation performance determined by both the spindle and bearings. In reality, there are variations in the characteristics of each component,
It is extremely difficult to avoid resonance point variations due to the influence of assembly conditions and achieve a spindle rotational precision of submicron order.

Generally, rolling bearings are used when such a high rotational load is required, but they have many disadvantages compared to sliding bearings. For example, since the effect of the oil film is very small, no damping effect can be expected, leading to shaft resonance and poor quality yvNr'! A lot of noise (imitation movement/sound) comes through from the non-performing artists. Furthermore, under adverse conditions, the shaft resonance and these bearing noises are superimposed, resulting in an increase in shaft runout, which may result in failures such as failure to fall within the standard rotational load. This is due to shaft vibration, in other words, the two-track track signal being transmitted on the magnetic disk fixed to the shaft fluctuates widely due to irregular rotational speed, making it impossible for the magnetic head to follow this. It is.

[Purpose of the invention]

Based on points such as the present invention e,
? In order to reduce vibration due to 111 resonance and #1+ runout due to vibration from the bearing to the shaft, a vibration damping device ff (was installed at the shaft end) to increase the spindle rotation by 16 degrees during actual operation. With the goal.

[Summary of the invention]

The present invention is characterized by a rotating magnetic disk,
In a magnetic disk device comprising a hub, a=nh, a pulley, a rolling bearing supporting these, and a base, the magnetic body provided at the end of the main shaft and the permanent magnet provided on the stationary side face each other, and the above-mentioned 11. It utilizes the magnetic attraction force (restoring ring) generated between the thruster and the permanent magnet to increase bearing rigidity in both thrust and axial directions and reduce up-shaft vibration.

[Embodiments of the invention]

An embodiment of the magnetic disk device of the present invention will be described below with reference to FIG.

In FIG. 2, a main shaft 1 is rotatably supported on a base 4 by rolling bearings 2 and 3. As shown in FIG. A hub 5 is attached to the main shaft 1, and a disk 6 is attached to the hub 5.
A large number of layers are stacked at regular intervals. A collar 7 is mounted between the rolling bearings 2.3 to keep the axial bearing spacing constant. Further, a pulley 8 is fastened to the lower end of the main shaft 1 with a bolt 9. By tightening the pulley 8, the rolling bearing 3 is preloaded in the axial direction by the coil spring 10 disposed inside the base 4. Numeral 11 is a belt that engages with the pulley 8 and is connected to a drive source (not shown) such as a motor. A concentric permanent magnet 12 is fixed to the base 4 so as to face one end of the pulley 8. Furthermore, the permanent magnet 12 is attached to one end of the pulley 8.
A magnetic body 13 is disposed at a position opposite to the magnetic body 13 with an appropriate gap therebetween. These constitute a vibration damping device 14.

With such a structure, the displacement of the main shaft l due to qQb resonance and the response of the main shaft 1 due to the vibration of the main shaft 1 from the rolling bearings 2 and 3 are generated in the gap between the magnetic body 13 and the permanent grinding stone 12. The magnetic attraction force can be significantly reduced. In the present invention, the magnetic attraction force is 1 in the thrust direction.
i14 Of course, an attractive force is generated in the axial direction due to the fact that the magnetic force 13 and the permanent magnet 12 described in 1111 are arranged concentrically. However, if the position is exactly the same, no axial suction force will be generated, but if the position is even slightly shifted, an attractive force (Kihara force) that tries to return to the center will be generated. In other words, the vibration mode of the shaft 1 (the bending mode of the shaft 1) which occurs in the actual machine operation state, and the main +1 + 411 wobbling ( For rigid body mode), the suction force blocks the main shaft 1 in both the thrust direction and the axial direction. This allows the vibration width of the valley formed in the bearing IS'L to be suppressed to a low amplitude response.

〔Effect of the invention〕

As described above, according to the present invention, the magnetic disk rotation fIv
This makes it possible to significantly improve the overall magnetic head positioning accuracy.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing a magnetic disk spindle system in a conventional magnetic disk device, and FIG. 2 is a partial cross-sectional view showing a magnetic disk spindle system in a magnetic disk device of the present invention.
It is a diagram. 1... Main shaft, 2, 3... Rolling bearing, 4... Pace, 5... Hub, 6... Magnetic disk, 8...
Pulley, 12Y 1 Figure 2

Claims (1)

[Claims] In a magnetic disk device consisting of a rotating magnetic disk and a main shaft to which the magnetic disk is fixed, which is supported by a rolling bearing placed on a base, a concentric magnetic body is installed in a part of the rotating main shaft system. A magnetism characterized in that a concentric permanent magnet facing the magnetic body is arranged on a part of the stationary side, and an allocation device is configured by utilizing the magnetic attraction force generated between the magnetic body and the permanent magnet. disk device.