JPH0148411B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a spindle bearing preload mechanism, and more particularly to a spindle bearing preload mechanism suitable for a magnetic disk device that requires precise rotational accuracy.

[Background of the invention]

In conventional rotating bodies, in order to reduce rotational runout and vibration due to the radial clearance of bearings, for example,
As described in Japanese Patent No. 58-184318, deformation of the bearing outer ring is avoided by eliminating the radial gap using a bearing housing and an axial preload spring. Furthermore, in order to restrain the bearing housing loosely inserted into the foundation base, the direction of radial preload is determined by actively restricting the contact between the foundation base and the bearing housing to a plurality of points.

However, applying preload in the radial direction of the bearing cannot prevent deformation of the bearing outer ring, which induces vibration and whirling of the spindle. Further, if the contact points with the base are made at a plurality of points other than three points, the static stability condition will not be satisfied and it will become unstable.

In particular, in order to promote higher-density recording in magnetic disk devices, it is necessary to position the relative positions of the magnetic head and magnetic disk with high precision. This has a negative impact on the recording density and becomes an obstacle to high-density recording.

[Purpose of the invention]

An object of the present invention is to solve the problems of the prior art as described above, by improving the radial clearance between the inner and outer rings of a bearing.
It is an object of the present invention to provide a preload mechanism for a spindle bearing that can prevent vibration and whirling of the spindle due to deformation of the bearing outer ring, etc., and can realize highly accurate rotation of the spindle.

[Summary of the invention]

In order to achieve the above object, the spindle bearing preload mechanism of the present invention includes a bearing that holds the rotating shaft of a rotating body, a bearing housing that holds the outer ring of the bearing, and a foundation base that supports these as a whole. A radial preload mechanism is disposed on the outer edge of the bearing housing, and the radial preload mechanism acts substantially tangentially to the outer ring of the bearing, and the bearing housing is located near a point symmetrical to the radial preload mechanism with respect to the center of the bearing housing. The present invention is characterized in that a stopper is provided to prevent rotation of the bearing housing, and the outer periphery of the bearing housing is configured to contact the basic base at three points including the stopper.

[Embodiments of the invention]

Hereinafter, the configuration of the present invention will be explained in detail using examples.

FIG. 2 is a diagram showing a spindle structure of a magnetic disk device to which a spindle bearing preload mechanism according to an embodiment of the present invention is applied. Note that the left side of FIG. 2 shows the external appearance, and the right side shows a longitudinal section.

In Fig. 2, 1 is the basic base, 2 is the spindle shaft, 3a and 3b are the lower and upper bearings of the spindle shaft 2, respectively, 4 is the bearing housing, 5 is the axial preload spring, 6 is the DC motor, and 7 is the In the magnetic disk, 8 is a hub, and 9 is a spacer.

The magnetic disk 7 is connected to the hub 8 via the spacer 9.
is fixed. A spindle shaft 2 supporting a hub 8 is rotatably supported by an upper bearing 3b and a lower bearing 3a, and is held on the foundation base 1. The inner ring of the upper bearing 3b is fixed to the spindle shaft 2, the outer ring to the basic base 1, and the inner ring of the lower bearing 3a is fixed to the spindle shaft 2. Lower bearing 3
The outer ring of a is fixed to the bearing housing 4,
A downward force is applied by an axial preload spring 5.

The bearing housing 4 applies the preload force of the axial preload spring 5 while in contact with the foundation base 1 from the outer ring of the lower bearing 3a to the bearing ball of the lower bearing 3a to the lower bearing 3.
The transmission takes place through the following path: inner ring of a → spindle shaft 2 → inner ring of upper bearing 3b → bearing ball of upper bearing 3b → outer ring of upper bearing 3b → foundation base 1, so the inner and outer rings of upper bearing 3b and lower bearing 3a Preload in the axial direction is added to reduce backlash.

FIG. 1 is an axial view of the spindle shaft 2, lower bearing 3a, and bearing housing 4 in FIG. 2.

The bearing housing 4 has a shape in which a portion of the circular outer shape is unevenly polished to smoothly reduce the radius of curvature between points 12 and 13, so that the bearing housing 4 contacts the basic base 1 at two points 12 and 13. A notch is provided in the outer edge of the bearing housing 4, and a radial preload mechanism 10 is provided in this notch so that the direction of force is tangential to the lower bearing 3a. spindle center 14
On the other hand, a similar notch is provided at a position symmetrical to the point of action of the radial preload mechanism 10, and a stopper 11 is provided so as to receive the rotational force applied to the bearing housing 4 by the radial preload mechanism 10 also as a tangential force. , so as to prevent rotation of the bearing housing 4. With this configuration, the force of the radial preload mechanism 10 and the reaction force of the stopper 11 push the bearing housing 4 in the direction in which points 12 and 13 contact the basic base 1. Therefore, the bearing housing 4 has three points: the stopper 11, the point 12, and the point 13.
The rotation center 14 of the spindle shaft 2 can be positioned at one point because it is restrained to the basic base 1 at a point and becomes statically fixed. Further, since the force acting on the bearing housing 4 is mainly a tangential force, deformation of the outer ring of the lower bearing 3a can be reduced.

As the recording density of magnetic disk devices increases, the positioning accuracy of the magnetic head is required to be higher and higher, and spindle whirling and vibration are also required to be minimized. Shaking of the rotation center 14 can be almost eliminated, making it possible to achieve high-density recording. Furthermore, since the deformation of the bearing due to preload is small, there is an effect of reducing vibration, and the life of the bearing is significantly increased. Furthermore, when considering automation of spindle assembly, the assembly workability of the radial preload mechanism 10 is generally poor, but in this embodiment, the radial preload mechanism 10 is
Since it is a single piece, it is easy to assemble and is suitable for automation.

Note that as the radial preload mechanism 10, a spring spring, an air spring, an O-ring, etc. can be used.

〔Effect of the invention〕

As explained above, according to the spindle bearing preload mechanism of the present invention, vibration and whirling of the spindle due to the radial gap between the inner and outer rings of the bearing, deformation of the outer ring of the bearing, etc. can be prevented, and high precision rotation of the spindle can be realized. Can be done.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a spindle bearing preload mechanism according to an embodiment of the present invention, FIG. 2 is a diagram showing a spindle structure of a magnetic disk device to which FIG. 1 is applied,
It is. 2: spindle shaft, 3a: lower bearing, 4: bearing housing, 10: radial preload mechanism, 11: stopper, 12, 13: contact point between bearing housing and foundation base, 14: spindle rotation center.

Claims (1)

[Claims] 1. In a spindle mechanism having a bearing that holds a rotating shaft of a rotating body, a bearing housing that holds an outer ring of the bearing, and a foundation base that supports these as a whole, a substantially tangent line of the outer ring of the bearing is attached to an outer edge of the bearing housing. A radial preload mechanism acting in the direction is disposed, a stopper for preventing rotation of the bearing housing is provided near a position symmetrical to the radial preload mechanism with respect to the center of the bearing housing, and the outer periphery of the bearing housing is A preload mechanism for a spindle bearing, characterized in that it is configured to contact the basic base at three points including a stopper.