JPS6211204B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention The present invention relates to a bearing structure that improves the rotation accuracy of a spindle.

Prior Art FIG. 1 shows an example of a spindle structure in a conventional disk drive device.

In FIG. 1, a plurality of magnetic disks 1 are fixed to a spindle hub 2. As shown in FIG. The spindle hub is rotatably attached to the base 4 via two upper and lower bearings 3a and 3b, and the motor magnet 5
The spindle hub is rotated around the shaft of the spindle hub by a drive motor constituted by a motor winding 6 and a motor winding 6. In order to improve the rotation accuracy of the spindle, it is necessary to eliminate the radial clearance between the inner and outer rings of the bearings 3a and 3b. For this purpose, a minute clearance is provided between the outer ring of the bearing 3b and the base 4, and the spring 7 applies axial preload to the outer ring of the bearing, thereby eliminating the radial clearance of each bearing. Ru. In order to prevent a decrease in rotation accuracy due to the clearance between the bearing outer ring and the base, a point on the outer ring of the bearing 3b is pressed in the radial direction by a spring 8 to eliminate the clearance between the bearing outer ring and the base.

However, in this structure, in order to eliminate the gap between the bearing and the base, the spring applies a radial force directly to the bearing outer ring, which tends to cause deformation of the bearing outer ring and reduce rotational accuracy. In addition, as shown in Figure 2, in the direction of the preload by the spring 8, the bearing and the base are in contact at two points 9 and 10, eliminating any gap, but in the direction perpendicular to the direction of the preload, there is a gap with no holding force. As a result, the shaft of the spindle tends to move easily, resulting in a decrease in rotational accuracy. Further, for the above-mentioned reason, the outer ring of the bearing 3b is not positively fixed to the inner surface of the base 4, so there is a possibility that the outer ring of the bearing also rotates during operation. This rotation of the outer ring also causes a decrease in rotation accuracy.

FIG. 3 shows an example of a spindle structure using a belt drive system. In this case, the motor is not directly installed on the hub 2, but the rotational force is applied by the belt 19.
In the belt-driven spindle structure, the operation is the same as in the example described above, except that the tension generated by the belt performs the same function as the spring 8 in the example shown in FIG.

OBJECT OF THE INVENTION The purpose of the present invention is to eliminate the above-mentioned conventional problems, and to provide a preload without deforming the bearing, and to stably eliminate the gap between the fitting part of the bearing and the base. The object of the present invention is to provide a spindle structure that enables highly accurate rotation.

A feature of the spindle structure of the present invention is that the outer ring of the bearing is surrounded by a ring-shaped retainer, and a fitting clearance is provided between the retainer and the base, making it possible to apply preload to the bearing. It is.
In addition, a radial force is applied to the cage to remove the gap between it and the base, but the contact surface between the cage and the base is not made into a perfect cylindrical surface, and the outer diameter surface of the cage is aligned with the inner diameter of the base. By forming the spindle into a curved shape that contacts at three points, it is possible to obtain a spindle structure that has a stable holding force in all directions of the rotating shaft. Furthermore, a combination of projections and depressions is provided on the fitting surface of the retainer and the base to serve as a rotation prevention mechanism for the bearing outer ring, and the retainer guides the spring for applying the preload to prevent misalignment of the preload spring. The goal is to prevent it.

Next, embodiments of the present invention will be described in detail using the drawings. FIG. 4 is a sectional view of a spindle structure showing one embodiment of the present invention. Components with the same reference numerals indicate the same components as in the example of FIG. 1 above.

The bearing 3b is fixed to a ring-shaped retainer 11 by press fitting or adhesive. In this example it is a ball bearing. The structure is such that a slight gap is provided between the cage 11 and the base 4, and the force of the spring 7 applies axial preload to the cage, that is, the outer ring of the bearing. Due to this axial preload, the bearing 3a,
The radial clearance between the inner ring and outer ring of 3b is removed. This minute clearance between the cage and the base is the clearance necessary to apply preload to the bearing.
Leaving it as it is is not preferable in terms of improving rotation accuracy. Therefore, in order to absorb this gap, a spring 8 is used to press the retainer in the radial direction at one point on the outer periphery of the cage via the receiving metal fitting 15. However, since the bearing is not directly pressed as in the conventional case, the bearing is deformed. Less is. In addition, in this embodiment, as shown in FIG.
It has a shape cut into 6. As a result, spring 8
When a preload is applied in the radial direction by Since it has a holding force against all kinds of external forces in the radial direction, it can provide stable support and achieve high-precision rotation. In particular, by setting the angle θ between the contacts 13 and 14 to 52 degrees with respect to the acting direction of the spring 8 in FIG. 5, a bearing support system having equal holding force in all radial directions can be constructed. Also, for the above reason, the outer ring of the bearing 3b is not actively fixed to the base 4, so
It may rotate during operation. This rotation of the outer ring is also unfavorable in terms of improving rotation accuracy. For this purpose, a pin 17 is press-fitted into the retainer, and together with the receiving fitting 15, constitutes a mechanism for preventing rotation of the outer ring of the bearing 3b. Further, the end face of the cage 11 is provided with a part 19 that covers the peripheral edge of the end face and a flange 18 extending from the part 19. The flange 18 has the function of defining the position of the spring 7 so that it does not shift in the radial direction, and the peripheral edge part 19 has the function of reinforcing the cage 11 against deformation in the radial direction. Even if the cage moves within the base due to shock or vibration, the spring 7 is guided so that it does not hit the inner surface of the base 4, so the cage will reproducibly return to its original position. Return to

FIG. 6 shows another embodiment of the invention. The only difference from the above embodiment is that the shape of the outer diameter of the cage 11 is provided with projections 19 and 20, and the rest is the same as the above embodiment.

Since the configuration is as described above, the following effects can be obtained in this embodiment.

1. By holding the bearing outer ring in a ring-shaped retainer and providing a fitting clearance between the retainer and the base, preload can be applied without deforming the bearing.

2 By devising the shape of the outer diameter of the cage,
A stable bearing support structure can be achieved by having three contact points between the base and the retainer (ie, the bearing outer ring).

3. The retainer and base can constitute a rotation prevention mechanism for the bearing outer ring.

4. By using the retainer to guide the preload spring and preventing contact between the preload spring and the base, it is possible to always return the retainer to a fixed position even if the retainer moves.

As described above, according to the present invention, a highly accurate bearing can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of the spindle structure of a conventional disk drive device, and Fig. 2 is a cross-sectional view taken along A-A in Fig. 1.
3 is a vertical sectional view of another conventional structure, FIG. 4 is a vertical sectional view showing an embodiment of the present invention, FIG. 5 is a sectional view taken along the line B-B of FIG. 4, and FIG. The figure shows an alternative embodiment to that of FIG. 1...Magnetic disk, 2...Spindle hub, 3
a, 3b...Bearing, 4...Base, 5...Motor magnet, 6...Motor winding, 7...Spring, 8...Spring,
9, 10... Contact point, 11... Cage, 12, 13,
14... Contact point, 15... Bracket, 16... Curved surface with different diameters,
17...pin, 18...pulley, 19...belt.

Claims (1)

[Claims] 1. A bearing, a bearing holding member having a cylindrical portion that holds the peripheral surface of the bearing, a base member that holds the outer periphery of the bearing holding member, and a spring that applies pressure to the bearing holding member in one direction in the radial direction. In the bearing device, the outer periphery of the bearing holding member has a curved shape that receives the pressure from the spring in contact with the inner periphery of the base member at a plurality of locations, and also receives the pressure by engaging with the spring and further supports the bearing. A bearing device comprising a protrusion that prevents rotation of a holding member.