JPH0386968A - Balance correcting mechanism for magnetic disk device - Google Patents

Abstract

PURPOSE:To automatically execute balance correction by providing a balancing case, which is formed in the shape of a cylinder arranged on a spindle part coaxially with a rotational center of a magnetic disks while filled with fluid in the internal part forming endless path on the upper part of the magnetic disks. CONSTITUTION:On the upper part of a magnetic disks 3, a balancing case 1 is provided to be arranged on a spindle part 20 coaxially with the rotational center of the magnetic disks, and equipped with the cylindrical cross section shape filled with fluid 10 in the internal part. When the rotational center of the balancing case 1 is changed, difference is generated in centrifugal force to be operated to this fluid 10 and by using a fact that the fluid 10 is gathered in the most distant part from the rotational center by the difference of the centrifugal force, the balance correction of the spindle part 20 is executed. Thus, the balance correction can be automatically executed for the whole spindle part 20.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a balance correction mechanism for a spindle part installed in a magnetic disk device, etc., and aims to provide a balance correction mechanism having a function of automatically performing balance correction. The balancing case is disposed on the spindle portion so as to share the center of rotation with the disk, and is equipped with an endless cylindrical balancing case on its outer periphery, the inside of which is filled with fluid so that it can flow.

[Industrial application field]

The present invention relates to a balance correction mechanism installed in a spindle of a magnetic disk device or the like.

[Conventional technology]

FIG. 3 is a partially cutaway side view showing the configuration of a magnetic disk device, and FIG. 4 is a schematic perspective view of essential parts showing a conventional balance correction method.

As shown in FIG. 3, the magnetic disk drive includes a spindle motor 15, a rotating section 12 that is rotationally driven by the spindle motor 15, and a shaft engagement hole 4 (
Equipped with a spindle section 20 consisting of a magnetic disk 3 arranged in such a way as to engage the magnetic disks 3 (see FIG. 4) and a disk clamp 25 for fixing these magnetic disks 3 stacked in a stacked manner to the rotating section 12 with a spacer 9 interposed therebetween. At the same time, an actuator (not shown) moves the radial direction (arrow c-c'
The magnetic head 50 is equipped with a magnetic head 50 that is driven in a direction (direction). The magnetic head 50 is positioned at a desired track on the magnetic disk 3, which is rotated at high speed by the spindle motor 15, and performs recording/reproduction. In the figure, 7 indicates a bearing that rotatably supports the rotating section 12, and 30 indicates a fixing screw used when fixing the disk clamp 25 to the rotating section 12.

In recent magnetic disk drives, in order to meet the industry's needs for smaller size and larger capacity, the trunk spacing between the magnetic disks 3 is becoming increasingly narrower. Therefore, if the spindle section 20 including the magnetic disk 3 is out of balance,
When in the on-track state, the magnetic head 50 causes positional fluctuation (a phenomenon in which the magnetic head deviates from a normal track and moves to another track), causing the magnetic disk device to malfunction.

FIG. 4 is a diagram showing a conventional balance correction method for the spindle section 20.

This balance correction method focuses on the fact that the diameter of the shaft holder hole 4 on each side of the magnetic disks 3 is larger than the diameter d of the rotating part 12, and by making these magnetic disks 3 eccentric in different directions, the spindle part This method corrects the balance of the entire 20.

Therefore, in this balance correction method, the eccentric direction of each disk differs depending on the number of magnetic disks 3 arranged on the rotating section 12. FIG. 4 shows a case where the number of magnetic disks 3 is two, and in this case, these magnetic disks 3 are inserted into the rotating section 12 from opposite directions (arrow R direction and arrow direction).
If the number of magnetic disks 3 is, for example, three, they are arranged so as to be pressed against the rotating part 12 from directions 120 degrees apart from each other.

[Problem to be solved by the invention]

However, even if the above-described work is carried out, it is not easy to correct the balance of the spindle section 20 as a whole because each component has its own imbalance.

The present invention has been made to solve this problem, and is configured to correct the balance of the entire spindle section 20 without being conscious of the balance of each component.

[Means to solve the problem]

As shown in FIG. 1, the balance correction mechanism of the magnetic disk device according to the present invention (hereinafter referred to as balance correction mechanism)
It is arranged on the spindle part 20 so as to share the rotation center with the magnetic disk 3 (see FIGS. 3 and 4), and has a cylindrical cross-sectional shape in which the fluid 10 is fluidly filled. It has a configuration in which a balancing case 1 having a structure is provided on the outer peripheral portion of the balancing case 1.

[For production]

Since this balance correction mechanism is equipped with a balancing case 1 on the outer periphery, the inside of which is filled with fluid 10 so as to be able to flow, when the center of rotation of the balancing case 1 changes, it acts on this fluid 10. This system corrects the balance of the spindle by using the principle that a difference occurs in centrifugal force and the fluid 10 gathers at the part farthest from the center of rotation due to the difference in centrifugal force.With this balance correction mechanism, the entire spindle balance correction is automated.

〔Example〕

EMBODIMENT OF THE INVENTION The present invention will be described in detail below based on embodiment figures.

FIGS. 1(a) and (bl) are a plan view and a sectional view taken along line X-X of the embodiment of the present invention, and FIG. 2 is a partially broken main part showing the mounting state of the balance correction mechanism according to the present invention. Although this is a side view, the same parts as in FIGS. 3 and 4 are given the same reference numerals.

As shown in FIGS. 1(a) and 1(bl), the balance correction mechanism 5 according to the present invention includes a main body portion 2 formed in a disc shape, and an endless cylindrical balancing case l provided on the outer peripheral portion of the main body portion 2. The inside of the balancing case 1 is filled with a fluid 10 such as mercury in a sealed state.The inside of the balancing case 1 is designed to prevent the flow of the fluid 10 filled therein. In order to prevent interference, lining processing is performed using, for example, fluororesin.In the figure, O indicates the structural rotation center of the balance correction mechanism 5 and the spindle section 20, and 31 is an insertion hole for a fixing screw 30 that fixes the balance correction mechanism 5 to the spindle portion 20.

As shown in FIG. 2, the balance correction mechanism 5 is mounted so as to share the rotation center ○ with the magnetic disk 3.

The operation of the balance correction mechanism according to the present invention will be explained below with reference to FIGS. 1 and 2. However, this explanation is based on the assumption that the structural rotation center of the spindle part (hereinafter referred to as the rotation center) ○ and the position of the center of gravity of the spindle part (hereinafter referred to as the center of gravity position) O' are misaligned as shown in Fig. 1 (al). This is based on the assumption that

■, Activate the device. As a result, the spindle part 20
causes rotational motion with O as the center of rotation.

(2) When the spindle 20 starts rotating, its center of gravity is at point O'', so as the rotational speed increases, the center of rotation of the spindle 20 moves from point 0 toward the center of gravity O''.

■As the rotation center of the spindle 20 moves from the 0 point to the 0'' point, it moves from the O'' point to the 0 point to A
The distance to the point, that is, the distance between O' and A, is 0
It is larger than the distance from point to point A, that is, the distance between 0 and A.

■The fact that the distance between O' and A is larger than the distance between O and A means that the effective radius of rotation of that part has become larger than the structural radius of rotation, and as a result, The fluid 10 in the balancing case 1 gathers near point A, where the centrifugal force is greatest.

(2) As the fluid 10 gathers near point A, the unbalance of the spindle part 20 is corrected, and the spindle part 20
0 means stable rotation.

In this embodiment, the balance correction mechanism 5 is configured as an independent single component, which is connected to the disk clamp 25.
Alternatively, the balancing case 1 may be provided within the spindle portion 20. Further, in this embodiment, the cross-sectional shape of the balancing case 1 is a rectangular tube shape, but it may be, for example, a circular tube shape.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the spindle section is operated automatically.

In addition, since the balance of the entire spindle section can be accurately corrected, the balance correction work of the spindle system can be made significantly more efficient.

[Brief explanation of drawings]

Figure 1 (al and (bl) are a plan view and a cross-sectional view taken along line X-X of the embodiment of the present invention; Figure 2 is a partially broken side view of the main part showing the mounting state of the balance correction mechanism according to the present invention. Figure 3 is a side sectional view of the main part showing the configuration of a magnetic disk drive, and Figure 4 is a schematic perspective view of the main part showing the conventional balance correction method. In the figure, ■ is a balancing case, 2 is a main body 3 is a magnetic disk, 4 is a shaft hole, 5 is a balance correction mechanism, 7 is a bearing, 9 is a spacer, 10 is a fluid, 12 is a rotating part, I5 is a spindle motor, 20 is a spindle part, 25 is a disk Clamp, 30 is a fixing screw, 31 is a screw insertion hole, 50 is a magnetic head, 0 is the structural rotation center of the spindle part, 0 is the center of gravity position of the spindle part, D is the diameter of the shaft insertion hole 4, d is the rotation The diameter of part 12 is shown respectively.

Claims (1)

[Claims] Spindle unit (20) installed in a magnetic disk device, etc.
The balance correction mechanism is arranged on the spindle part (20) so as to share the center of rotation with the magnetic disk (3), and has a fluid (10) inside.
1. A balance correction mechanism for a magnetic disk drive, characterized in that the outer periphery of the balancing case (1) is equipped with an endless cylindrical balancing case (1), which is filled with fluidically filled with (1).