JP2623645B2 - Unit bearing for rotary actuator of magnetic disk drive and fixed position preload method for unit bearing - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a unit bearing having no spacer suitable for a rotary actuator of a magnetic disk drive, and a method of preloading the unit bearing in a fixed position.

2. Description of the Related Art In recent years, small magnetic disk drives have become increasingly thinner, and the spacing between unit bearings of a rotary actuator has become narrower. For example, as shown in FIG. 3, the outer ring 1.1 'of a unit bearing provided with a sealing plate 10.10' is provided. Between the thin spacers 2
A fixed position preloading method in which a thrust load is applied by screwing a screw 5 into the shaft 4 of the inner ring 3.3 'through the shaft 4 is known.

As shown in FIG. 4, a coil spring 13 (one end of the coil spring 13 abuts on the end plate 14 between the outer ring 1.1 'of the rolling bearing facing the wide unit bearing and the inner flange 12 of the casing 1). , The other end is housed in an annular tubular body 15,
Is in contact with the outer ring 1 '. A constant pressure preloading method in which a thrust load is applied by using a component having a large elasticity as in (1) is known.

The former has the advantage that it is simple as a method of increasing the rigidity by applying a preload to the rolling bearing, and the latter has the advantage that the amount of preload does not change even if the position of the bearing slightly changes during rotation of the rolling bearing.

However, if the spacer 2 in the former case is assembled on a business trip from the outer ring 1.1 ', the spacer 2 may not be mounted as specified when it is mounted on the magnetic disk drive.

Further, since the inner ring 3 ′ is press-fitted into the shaft 4 by the screwing force of the screw 5, the press-fit position of the inner ring 3 ′ is not constant depending on the screwing state of the screw 5. The most important torque as a unit bearing for a rotary actuator of a disk device varies.

In order to keep the torque value within a certain value, it is necessary to adjust and manage the screws 5, but it is very difficult.

In addition, the latter requires a component other than the rolling bearing, such as the coil spring 13, and has a disadvantage that the dimension around the bearing is increased.

SUMMARY OF THE INVENTION An object of the present invention is to provide a unit bearing and a method for preloading the bearing in a fixed position, which can facilitate assembly of a unit bearing for a rotary actuator of a magnetic disk drive and management of a constant required torque of the unit bearing.

"Means for Solving the Problems" In order to achieve the above object, in the present invention, one or both outer rings of two single row deep groove ball bearings with seals attached to a shaft body are connected to the other outer ring. On the other hand, the side which is opposed to and in close contact with the inner ring is made to protrude in the axial direction from the width of the inner ring to provide a unit bearing for a rotary actuator of a magnetic disk drive in which a bearing interval is maintained.

Further, both outer rings of the two rolling bearings attached to the shaft body are made to protrude in the axial direction from the inner ring width so that the side of the outer ring that opposes and adheres to the other outer ring maintains the bearing interval. By bringing the rolling bearings into close contact with each other, it is possible to omit the inner shield of the rolling bearing, thereby obtaining a unit bearing for a rotary actuator of a magnetic disk drive.

Further, as the fixed position preloading method of the bearing, one or both outer rings of the two rolling bearings attached to the shaft body project in the axial direction from the inner ring width on the side which is in close contact with the other outer ring in close contact with the other outer ring. In addition, it is necessary to maintain a bearing interval, and then apply a constant-pressure preload to the inner ring of the rolling bearing, and thereafter fix the inner circumference of the inner ring to the outer circumference of the shaft, thereby equalizing the fixed position preload.

[Operation] By the above technical means, the spacer and the outer ring of the unit bearing for the rotary actuator of the magnetic disk drive are integrally formed, and the business travels from the outer ring outer periphery as if there was a spacer. There is absolutely no such problem, and there is no trouble at the time of being incorporated in the magnetic disk device.

Further, since the magnetic disk is provided with the seal, there is no grease leakage harmful to the magnetic disk.

The inner ring is fixed to the shaft by applying a constant-pressure preload to the shaft so as to set the preload at a fixed position. Therefore, a desired constant torque can be obtained after the completion of the unit bearing for the rotary actuator of the magnetic disk drive.

Example An example will be described with reference to the drawings.

FIG. 1 is a sectional view of a unit bearing for a rotary actuator of a magnetic disk drive according to the present invention, and FIG. 2 is a sectional view showing another embodiment of the present invention.

In FIG. 1, an outer ring 101 of a rolling bearing 100 is formed with a wide portion 1011 protruding in the axial direction in order to maintain an interval with an outer ring 102 of a rolling bearing 100 'opposed thereto. The circumference 1012 is formed to have the same inner diameter as the inner circumference 1021 of the facing outer bearing 102, that is, the opposing rolling bearing 102.

In the drawing, reference numeral 103.104 denotes an inner ring, 105.106 denotes a retainer for holding and guiding the ball 107 at a required interval, 108.109 denotes a sealing plate mounted on the end face side of the outer ring 101.102, and 108'.109 'denotes opposed end faces of the outer ring 101.102. Sealing plate mounted on the side, 1
10 is a shaft having a flange, 130 is an adhesive, 140 is a receiving jig having a guide hole 141 formed in the center, 150 is a pressing member 151 with a flange and an outer pressing member 15 fitted to the pressing member 151.
This is a pressing jig in which a coil spring 153 is inserted between the two.

Since the rotary actuator unit bearing of the magnetic disk drive according to the present invention is configured as described above, the outer circumference of the shaft 110 or the inner race 104 of the rolling bearing 100 'is previously determined.
After the adhesive 130 is applied to the inner periphery 1041 of the shaft 110, the adhesive 130 is inserted into the shaft 110, placed on the receiving jig 140, and then the coil spring 153 is inserted between the flanged pressing member 151 and the outer pressing member 152. By pressing the tool 150 against the inner ring 104 and applying an external force in the direction of the arrow 154, the elasticity of the coil spring 153 acts and a constant constant-pressure preload acts.

After a predetermined time has passed and the adhesive 130 has hardened, the receiving jig 140 and the pressing jig 150 are removed, so that a fixed position preload is maintained between the rolling bearings 100 and 100 '.

The relationship between the pressure (elasticity) of the coil spring 153 and the torque required for practical use of the unit bearing for the rotary actuator of the magnetic disk drive can be obtained by preparing the necessary data in advance through experiments to always apply a constant pressure to the rolling bearing. Since it can be added, the required value of torque is obtained.

FIG. 2 shows another embodiment of the present invention.
0 ′ outer ring 101.102 is projected in the inner axial direction by a half of the interval, and the sealing plate 108′.109 ′ of the bearing 100.100 ′ can be omitted, so that the space volume of the opposed rolling bearing can be increased. Can be.

Therefore, the amount of grease enclosed between the rolling bearings increases, and the life of the unit bearing for the rotary actuator of the magnetic disk device is prolonged accordingly.

[Effect of the Invention] Since the present invention is configured as described above,
The following effects are obtained.

The opposing sides of the outer ring of the unit bearing for the rotary actuator of the magnetic disk drive are in close contact with each other, and the inner ring of one of the rolling bearings is fixed to the shaft.Therefore, there is no displacement of the outer ring, no grease leakage, and a leakage prevention function. Can work effectively.

In addition, since the sealing plate inside the rolling bearing can be omitted, the space capacity of the rolling bearing can be increased, and the lubricating function that can increase the amount of grease filling related to the life can be further enhanced.

Further, the unit bearing for the rotary actuator of the magnetic disk drive of the present invention does not require the machining of parts such as spacers, screws or coil springs and the internal threading of the shaft. It has a significant effect on the above.

Further, since the number of parts is small and the assembling property is easy, the working time can be reduced, and a great advantage can be obtained in terms of cost.

In particular, the unit bearing for the rotary actuator of the magnetic disk drive of the present invention can make the most important torque a constant value by using both the constant pressure preload and the fixed position preload.

[Brief description of the drawings]

1 is a sectional view of a unit bearing for a rotary actuator of a magnetic disk drive according to the present invention, FIG. 2 is a sectional view showing another embodiment of the present invention, and FIG. 3 is a rotary view of a magnetic disk drive using spacers. FIG. 4 is a sectional view showing a conventional example of a unit bearing for an actuator, and FIG. 4 is a sectional view showing a conventional example of a unit bearing for a rotary actuator of a magnetic disk drive using a coil spring. Description of reference numerals 100.100 ': rolling bearing, 101.102: outer ring 1011: wide portion of outer ring, 103.104: inner ring 110: shaft, 130: adhesive

Claims (3)

(57) [Claims] 1. One or both outer races of two single row deep groove ball bearings with seals attached to a shaft body are made to protrude in the axial direction from the inner race width on the side which is in close contact with the other outer race. A unit bearing for a rotary actuator of a magnetic disk drive, wherein a bearing interval is maintained. 2. An outer ring of two rolling bearings assembled to a shaft body has a side opposed to and in close contact with the other outer ring projected in the axial direction from an inner ring width to maintain a bearing interval, and ,
A unit bearing for a rotary actuator of a magnetic disk drive, wherein an inner shield of the rolling bearing can be omitted by bringing the outer ring sides into close contact with each other. 3. One or both outer races of the two rolling bearings mounted on the shaft body protrude axially from the inner race width on a side facing and closely contacting the other outer race to maintain a bearing interval. After that, after applying an initial constant-pressure preload to the inner race of the rolling bearing, the inner periphery of the inner race is fixed to the outer periphery of the shaft, so that the fixed position preload is performed. Preload method.