JPS58133673A - Magnetic disc pack - Google Patents

Abstract

PURPOSE:To attain dynamic balancing of a magnetic disc pack rotating body simply in a short time with high precision, by holding plural steel balls so as to be moved in a ring shaped groove formed with an inner and an outer wheels having a metallic ball guide orbit. CONSTITUTION:In dynamically balancing the magnetic disc pack, first a magnetic disc pack assembly is fitted to a dynamic balancing machine. In this state, a plurality of steel balls 6 are freely moved in the ring shaped groove 29 formed with an inner and outer wheel 4 of the ring shaped steel guide orbit made of a shape storage alloy and a ring shaped steel ball guide orbit 5. In rotating the magnetic disc pack to attain dynamic balance, plural steel balls 6 is moved to a position to cancel unbalanced mass of the magnetic disc pack. In this state, the outer wheel 4 of the guide orbit is expanded in blowing cold air or carbon dioxide to the outer wheel 4 of the guide orbit of the steel balls made of the ring shaped storage alloy, plural steel balls 6 are fixed and the mass of the rotating body is balanced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic disk park, and more particularly to a magnetic disk back that eliminates the initial dynamic unbalance of a magnetic disk pack rotating body at least when a magnetic disk is loaded.

The replaceable magnetic disk pack used in magnetic disk storage devices suppresses dynamic vibrations caused by mass imbalance during steady rotation, and supports the magnetic recording converter (magnetic head) and recording medium (magnetic head) carried by the magnetic disk device. In order to maintain a stable mutual positional relationship of the disks, it is required that the amount of dynamic unbalance be below a certain tolerance value in the final mounted state of the rotating body.

Figure 1 is an exploded perspective view of a general magnetic disk back. %1 is a trim shield, 2 is a clamp ring, 3 is a hub, 7 is a magnetic disk, 8 is a magnetic disk spacer,
9 is the upper protective disk, 10 is the lower protective disk %, 11 is the lower clamp, 12 is the trim shield cover, 13 is the upper cover, 14 is the lower cover, 15 is the spindle lock, 16
is the 7-toe bearing, 17 is the 7-rexyapa, de, I
To adjust the amount of dynamic unbalance, place it in a dynamic balance tester before attaching the pack cover and rotate it to bring the amount of dynamic unbalance to a certain standard value to almost zero, as shown in Figure 1. The method used was to attach an appropriate mass to the surface of the trim shield 1 or the clamp lift 2 using an appropriate adhesive or adhesive tape on both sides.

However, this method takes time to achieve dynamic balance of the rotating body, and the adhesive surface is weak after long-term use, and the attached mass moves during rotation, causing dynamic imbalance. In extreme cases, it may completely peel off and cause internal damage.

The present invention eliminates the drawbacks of the above-mentioned conventional methods for dynamically balancing magnetic disks and rotating bodies, and more easily and accurately moves magnetic disks and rotating bodies in a single time. To provide a magnetic disk pack that makes it possible to balance targets.

According to the present invention, in a plane substantially perpendicular to the rotation axis of a magnetic disk pack support that rotates while supporting a magnetic disk,
An inner ring of an annular metal ball guide track and an outer ring of an annular metal ball guide track made of a shape memory alloy are provided, and a plurality of steel balls are provided so as to be movable in the annular groove formed by the inner ring and the outer ring of the metal ball guide track. A magnetic disk drive characterized by holding a ball is obtained.

In the present invention, a shape memory alloy is used, and the atoms in the shape memory alloy form a regular lattice as a phase that is stable at high temperatures. When this regular lattice phase is rapidly cooled and plastically worked, the atoms constituting the alloy work together to form a martensitic phase (this is called rutinsite transformation) at a very short distance. When 2:, the volume expands greatly. When the shape memory alloy in this state is heated, a reverse transformation occurs in which the martensitic phase returns to its original regular lattice phase, returning to its original shape.

In terms of energy, it is best for the reverse transformation of nickel to reversibly return to a regular lattice state, and this reversible change is the mechanism of the shape memory effect of shape memory alloys. is TI-Nl, Cu-Zf
Alloys such as i-An and Cu-N1-An are used.

Next, an embodiment of the magnetic disk drive according to the present invention will be described with reference to the drawings.

FIG. 2 is a side view showing a part of an embodiment of the magnetic disk drive according to the present invention in cross section, and FIG. 3 is an enlarged view of section A in FIG. In the figure, 3 is I%p.

4.5.6 are elements constituting a dynamic balancing mechanism using a shape memory alloy, which is a feature of the present invention. 4 is an outer ring of an annular steel ball guide race made of a shape memory alloy, and 5 is an annular steel ball guide race made of the shape memory alloy. The inner ring of the annular steel ball guide raceway is combined with the outer ring 4 of the steel ball guide raceway to form an annular groove that can freely move and guide a plurality of steel balls 6. The outer ring 4 and the inner ring 5 are used to rotate the disc. It is attached to /-p 3 in a plane perpendicular to the axis.

That is, for example, the inner ring 4 of the annular steel ball guide raceway is fixed to one end of the /SP 3 by a method such as press fitting.

When dynamically balancing the magnetic disk space.

First, attach the magnetic disk brake assembly to the dynamic balance tester. In this state, as shown in Figure 4, it is placed so that it can move freely inside. Therefore, when the magnetic disk pack is rotated to achieve dynamic balance, the magnetic disk pack
The plurality of steel balls 6 move to positions that cancel out the mass imbalance. In this state, when the outer ring 4 of the guide track of the annular shape memory alloy steel ball is rapidly cooled by blowing cold air or carbon dioxide, the outer ring 4 of the guide track expands.

A plurality of steel balls 6 are fixed as shown in FIG. 5, and the mass of the rotating body is kept balanced.

Fig. S shows the outer ring 4 of the shape memory alloy steel ball guide raceway holding down the steel balls 6 when the steel balls 6 are located at a position where the magnetic discs cancel out the mass unbalance of the rotating body. It shows the attached state.

In order to return this state to the state shown in FIG. 4, hot air is blown onto the outer ring 4 of the steel ball guide raceway made of an annular shape memory alloy.

The mass unbalance achieved by the above method is negligibly small, and is sufficiently small compared to the standard value of dynamic unbalance for magnetic disk packs, 10 IC1l, yielding satisfactory results.9.

As explained above, the present invention eliminates the drawbacks seen with the conventional method of adding mass, and allows dynamic balance to be achieved simply and with high precision in a very short period of time, and is very effective in practice.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a magnetic disk pack showing each component of the magnetic disk pack, FIG. 2 is a partially sectional side view of a main part of an embodiment of the magnetic disk pack according to the present invention, and FIG. 2 is an enlarged view of section A in FIG. 2, and FIGS. 4 and 5 are views showing one state of FIG. 3, respectively. l...Trim shield% 2...Clamp ring. 3... Hub, 4... Outer ring of steel ball guide raceway made of shape memory alloy, 5... Inner ring of steel ball guide raceway, 6... Steel ball . Figure 1 Figure 3 Figure 4 Sister figure 5

Claims (1)

[Claims] The inner ring of the annular metal ball guide track and the outer ring of the annular metal ball guide track made of a shape memory alloy are placed inside the magnetic disk which carries and rotates the magnetic disk, and is substantially perpendicular to the rotational axis of the support. 1. A magnetic disk drive comprising: a plurality of metal balls; and holding a plurality of metal balls so as to be movable in an annular groove formed by an inner ring and an outer ring of the metal ball guide track.