JPH04137263A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To effectively reduce thermal off-track by differenciating each relief angle theta of the bearing housings of both ends of a spindle. CONSTITUTION:The angle theta of run off 12 provided on bearing housings A13 and B14 which are attached to both ends of a shaft 3 is differenciated between the bearing housings A13 and B14. When the holes on a base plate 8 in which the outer wheels of the bearing housings enter are expanded to a constant degree due to a change in temperature, since a load is added to the run off part 12 by a radial spring 9 from the opposite direction from the run off part 12, and because the angle theta of the run off part 12 is different, the amount of displacement in the center of the shaft 3 is different between the side of the bearing housing A13 and the side of the bearing housing B14. Using this difference, the inclination of the spindle is corrected. Thus, the inclination of the spindle due to the change in temperature is corrected and the thermal off-track is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and particularly to a magnetic disk device that takes into consideration a spindle preload structure.

[Conventional technology]

In recent years, magnetic disk devices have increased storage density as well as increased storage capacity. For this reason, increasing importance is placed on improving the positioning accuracy of the magnetic head with respect to the magnetic disk.

The magnetic head positioning device in current magnetic disk drives has a servo head dedicated to positioning, and this servo head reads positioning information pre-recorded on the magnetic disk surface and performs positioning based on the read information. There is. Therefore, the relative displacement amount between the servo head and other data heads and the relative displacement amount between the servo disk on which positioning information is written and other data disks are the deviation amount from the trunk that should originally be tracked. This is the off-track amount. The smaller the off-track amount, the higher the positioning accuracy.

However, in reality, an amount of off-track that is more than permissible may occur due to various factors. Of this amount of off-track, off-track caused by a rise in device temperature or a change in environmental temperature is called thermal off-track, and the main cause is the difference in linear expansion coefficient between the various mechanical parts that make up a magnetic disk device. It is considered.

A conventional example is shown in FIGS. 5 and 6. Of these, in FIG. 5, a spindle hub 2 holding a magnetic disk 1 is fixed to a shaft 3. Inner rings of first and second bearings 4.5 are press-fitted into both upper and lower ends of the shaft 3. A bearing housing 6.7 is fixed to the outer rings of the first and second bearings 4.5, respectively.

A radial spring 9 is attached to the outer ring of the bearing housing 6.7 for pressing the bearing housing 67 against one direction of the base plate 8 to remove looseness. A plan view showing the positional relationship between the bearing housing 6, the base plate 8, and the radial spring 9 in a plane is shown in FIG. In FIG. 6, in order to further stabilize the position of the base plate 8 and the bearing housing 6, a nip portion 12 is provided on the outer ring of the bearing housing 6 or on the base plate 8 side at a bearing housing sitting angle θ. By providing this ribbed portion 12, the bearing housing 6 reliably contacts the base plate 8 at two points (both starting points of the ribbed portion), and the positional relationship between the spindle hub 2 to which the magnetic disk 1 is fixed and the base plate 8 can be more accurately determined. It is kept in The bearing 5, bearing housing 7, and base plate 8 attached to the other end of the shaft 3 also have a similar structure.

On the other hand, a positioner IN carrying a magnetic nod 10 is also fixed on the base plate 8, and has a structure that allows accurate positioning of the magnetic nod 10 on the magnetic disk 1.

However, in reality, the base plate 8 deforms due to temperature changes, causing the spindle to tilt relative to the positioner, causing thermal off-trunk.

[Problem to be solved by the invention]

As mentioned above, with the increase in capacity of recent magnetic disk drives, the thermal off-track tolerance is extremely small at 1 to 2 [μm], and in the conventional magnetic disk drives mentioned above, the thermal off-track tolerance exceeds the off-trunk tolerance. The problem arises that there is a fear.

[Object of the Invention] The present invention improves the disadvantages of the conventional example, and in particular reduces thermal off-track by correcting the inclination of the spindle caused by temperature changes, thereby providing a magnetic disk device with high reliability. can be provided.

[Means for Solving the Problems] The present invention includes a spindle hub that fixes and supports a plurality of magnetic disks at regular intervals, a shaft that fixes and supports the spindle hub, and a shaft that holds both ends of the shaft separately. first and second bearings;
A magnetic disk device comprising: a base plate that supports a bearing of the magnetic disk via a bearing housing; a plurality of magnetic heads installed to face each recording surface of a plurality of magnetic disks; and a positioner that positions each magnetic head. , on the outer periphery of the first and second bearings,
A first spring and a second spring are respectively provided to apply a fixed pressing force toward the center of each bearing, and the first and second springs are provided at the outer periphery of each bearing housing.
A configuration is adopted in which a cutout is provided at a portion located on the side opposite to the spring side of the bearing, and the spread angles of the cutout with respect to the center of the bearing are set to different sizes. This aims to achieve the above-mentioned purpose.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

The embodiment shown in FIGS. 1 to 4 differs from the conventional example described above in the following points. That is, in this embodiment, the angle θ of the nipped portions 12 provided on the bearing housings A13 and B14 attached to both ends of the shaft 3 (the angle connecting the center of the shaft and the starting point of the nipped portions 12 provided on the outer rings of the bearing housings A13 and B14) angle) is different between bearing housings A13 and 814. That is, the spindle tilts due to deformation of the base plate 8 due to temperature changes. In order to correct this, the bearing housings A13 and B14 are
The angle θ is different.

This is the bearing housing A13 as shown in Figure 1.
．． If the hole in the base plate 8 into which the outer ring of B14 is inserted expands a certain amount due to temperature changes, bearing housing A13.
In B14, since the radial spring 9 applies a load to the nipped part 12 side from the opposite direction of the nipped part 12, the angle θ of the nipped part 12 of the bearing housings A13 and B14 is different, so that the bearing housing A13 side and the bearing housing side are different. The inclination of the spindle is corrected by using the fact that the displacement amount of the center of the shaft 3 is different on the B14 side.

Figure 4 shows the diameter of the bearing housing: φ68mm.
This figure shows the relationship between the displacement amount and the nip angle θ when the temperature difference is 40 ("C") and the expansion coefficient is 17X10.

Other configurations and effects are the same as those of the conventional example described above.

In addition, bearing housing A13. The relief part 1 is not provided on the outer ring of B14, but the relief part 1 is provided on the large side of the base plate 8.
2 and the angle θ of each negated portion 12 is made different,
It has the same effect as above, and bearing housing A13. A similar effect can be obtained even if the outer ring diameter of B14 is varied.

[Effects of the Invention] As described above, according to the present invention, by making the deflection angle θ of the bearing housings at both ends of the spindle different, the inclination of the spindle due to temperature changes is corrected, thereby effectively reducing thermal off trunk. It is possible to provide an unprecedented and excellent magnetic disk device that has the effect of obtaining a highly reliable magnetic disk device that can perform the following steps.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
An explanatory diagram showing the relationship between the upper radial spring and the bearing housing section A as seen from the X direction in the figure, FIG. 3 is an explanatory diagram showing the relationship between the lower radial spring and the bearing housing section 8 as seen from the Y direction in FIG. 1, Fig. 4 is a graph showing the amount of displacement with respect to the deflection angle θ, Fig. 5 is a sectional view showing a conventional example, and Fig. 6 is an explanatory diagram showing the upper radial spring and the bearing housing A part as viewed from the X direction in Fig. 5. It is. 1...Magnetic disk, 2...Spindle huff, 3...Shaft, 4...First
bearing, 5...Second bearing, 6.
...Bearing housing, 7...Bearing housing, 8...Base plate, 9
... Radial spring, 10 ... Magnetic head, 11 ... Positioner, 12 ...
...Negation part, 13...Bearing housing A
, 14... Bearing housing B0 Applicant: Japan Electric Co., Ltd. (and one other person) Agent: Patent attorney Isamu Takahashi Figure 1 1... Magnetic disk 2... Spindle hub 3... Shaft 4... First bearing 5... Second bearing 6... Bearing housing 7... Bearing housing 8... Base plate 9... Radial spring lO... Magnetic head 11... Positioner 12... -・Negated part 13・・・Bearing housing A 14・・・Bearing housing B Fig. 3 (shaft) Fig. 14 (Bearly〉7paja wind end B) Fig. 4 [Two-dimensional] θ Fig. 5 Fig.

Claims (1)

[Claims] (1) A spindle hub that fixes and supports a plurality of magnetic disks at equal intervals; a shaft that fixes and supports the spindle hub; first and second bearings that separately hold both ends of the shaft; a base plate that supports first and second bearings via a bearing housing; a plurality of magnetic heads installed to face each recording surface of the plurality of magnetic disks; and a positioner that positions each of the magnetic heads. In the magnetic disk drive equipped with the above, first and second springs are provided on the outer peripheries of the first and second bearings, respectively, each of which biases a certain pressing force toward the center of each of the bearings. , a cutout is provided at a portion of the outer periphery of each of the bearing housings located on the side opposite to the first and second spring sides, and the spread angle of the cutout with respect to the center of the bearing is set to a different size. A magnetic disk device characterized by being set to