JPH10267036A - Disk drive - Google Patents

Abstract

(57) [Problem] To provide a disk drive device in which a non-rotational synchronous component has a small run-out, a small starting torque, and is easy to inject and assemble a lubricant. SOLUTION: In a disk drive device in which a rotating body on which a disk can be mounted is rotationally driven by a motor, the rotating body is rotatably supported by a support member via a radial dynamic pressure bearing and a thrust bearing. An axial load is applied by a magnetic attraction force equal to or greater than the body's own weight and equal to or less than 30 N. Further, one of the rotating body and the support member has a shaft, and the end surface of the shaft constitutes a thrust bearing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to information equipment,
The present invention relates to a video device, particularly a disk drive device used for an optical disk device or a magnetic disk device.

[0002]

2. Description of the Related Art Conventionally, a disk drive has a structure as shown in FIG. That is, the rotating body 20 on which the disk can be mounted is rotatably supported by the shaft 21 via the two ball bearings 23, and the lower end of the shaft 21 is fixed to the base 27. The rotating body 20 and the disk mounted on the rotating body 20 are driven to rotate by a motor M2 inserted between the base 27 and the rotating body 20. The motor M2 has a rotor 28 fixed to the rotating body 20 and a stator 29 fixed to the base 27.

[0003]

As the recording density of magnetic disk devices has been increasing, it has been required for disk drive devices used therein to have small fluctuations of non-rotational synchronous components.

In a conventional disk drive, a ball bearing 23 has been used as shown in FIG. The ball bearing 23 is required to have a small non-rotation synchronous component runout. However, the ball bearing 23 has ball passing vibration and vibration caused by a shape error of the bearing component, and it is difficult to reduce the run-out of the non-rotational synchronous component to a value equal to or less than a predetermined value even if the processing accuracy is improved. is there.

On the other hand, a disk drive device as shown in FIG. 6 in which a dynamic pressure bearing having a small runout of a non-rotational synchronous component is used for both a radial bearing and a thrust bearing instead of the ball bearing 23 is being studied. In this example, the shaft 3 fixed to the base 27
The thrust bearings are provided on both side surfaces of the flange portion 24 provided on the disk drive device 0 so that the disk drive device can be adapted even when the usage posture of the disk drive device changes. I try not to fall off.

However, in this case, since an axial load is applied to the flange portion 24 having a large area,
There is a problem that the starting torque is large. Further, since the shaft 30 is inserted into the rotating body 20 due to the presence of the flange portion 24, it is necessary to fix the thrust plate 22 constituting the rotating body to the hub 27 constituting the rotating body. There is a problem that is difficult.

[0007] The present invention focuses on the above problems,
Non-rotational synchronous component swing is small, starting torque is small,
Moreover, it is an object of the present invention to provide a disk drive device that can easily inject and assemble a lubricant.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a disk drive device in which a rotating body on which a disk can be mounted is driven to rotate by a motor, wherein the rotating body includes a radial dynamic pressure bearing and a thrust bearing. The thrust bearing is rotatably supported by a support member. An axial load is applied to the thrust bearing by a magnetic attractive force of 30 N or less, which is equal to or more than its own weight of the rotating body, and one of the rotating body and the supporting member has an axis. And the end face of this shaft constitutes a thrust bearing.

The disk drive of the present invention may be provided with a motor having a rotor fixed to a rotating body and a stator fixed to a support member. An axial load may be applied to the thrust bearing by a magnetic attraction force between the rotor and the stator that is equal to or greater than the weight of the rotating body and equal to or less than 30 N.

[0010]

According to the present invention, since the rotating body is supported by the radial dynamic pressure bearing and the thrust bearing constituted by the shaft end face, the non-rotational synchronous component has a small swing and the starting torque is small. Further, since a predetermined magnetic attraction force is applied in the axial direction, there is no restriction on the use posture. further,
Since there is no need to provide a flange portion for receiving an axial load on the shaft, assembly is easy.

[0011]

FIG. 1 shows a first embodiment. The rotating body 10 on which the disk 13 can be mounted has a hub 40 and a shaft 1 fixed to the hub 40, and the shaft 1 is fitted to the sleeve 6. The base 7 is fitted and fixed to the outer peripheral surface of the lower end of the sleeve 6,
A thrust plate 2 for closing the cylindrical hole of the sleeve 6 and a steel plate holder 5 disposed in contact with the lower surface of the thrust plate 2 are fixed to the base 7. The retainer 5, the thrust plate 2, the base 7, and the sleeve 6 constitute a support member 42. The radial bearing surface 41 provided on the inner diameter surface of the sleeve 6 and the outer diameter surface of the shaft 1 constitute a radial dynamic pressure bearing 4, and the end surface of the shaft 1 and the thrust bearing surface provided on the thrust plate 2 constitute the thrust bearing 3.
Is configured. The rotating body 10 is rotatably supported by the support member 42 via the radial dynamic pressure bearing 4 and the thrust bearing 3. A retaining member 11 is fixed to an outer peripheral portion of the support member 42, and an outer peripheral portion of the rotating body 10 has an upper surface opposed to the retaining member 11 via an axial clearance and a lower surface via an axial clearance to the supporting member 42. Are facing each other. The thrust plate 2 has a groove for generating dynamic pressure on a thrust bearing surface cooperating with the shaft 1, and the thrust bearing 3 constitutes a thrust dynamic pressure bearing. Further, the outer peripheral surface of the shaft 1 has a groove 44 for generating dynamic pressure, and constitutes a radial dynamic pressure bearing 4.

When the thrust plate 2 is made by injection molding of plastic, a groove for generating dynamic pressure can be formed by molding, and can be manufactured at low cost. In particular, it is preferable to manufacture the resin based on PPS (polyphenylene sulfide resin) by injection molding of a plastic to which carbon fiber and Teflon (registered trademark), that is, polytetrafluoroethylene are added, because it is excellent in slidability, strength, and moldability.

When the axial load is small, a steel plate holder 5 for reinforcing the plastic thrust plate 2 is used.
May be omitted. Further, the thrust plate 2 and at least one of the end surfaces of the shaft 1 are formed as convex spherical surfaces to support the rotating body 10 in point contact, by omitting a groove for generating a dynamic pressure for the thrust bearing.
A so-called pivot bearing may be used.

On the other hand, when the radial dynamic pressure bearing 4 uses the sleeve 6 made of a copper-based material, a groove for generating dynamic pressure can be easily provided on the inner diameter surface of the sleeve 6. When the sleeve 6 is made of a copper-based material, the stainless steel shaft 1
With good sliding properties and excellent start / stop durability.

Since the sleeve 6 and the thrust plate 2 are directly fixed to the base 7, the assembling is easy and the reliability is excellent. The motor M has a rotor 8 fixed to the rotating body 10 and a stator 9 fixed to the support member 42, and the rotating body 10 is driven to rotate by the motor M. By displacing the axial center of the rotor 8 and the axial center of the stator 9 facing each other in the radial direction in the axial direction, the thrust bearing 3 is provided with a magnetic attraction force equal to or greater than the weight of the rotating body 10 and equal to or less than 30N. Axial load is applied. Preferably, the magnetic attraction in the axial direction is at least twice the own weight of the rotating body 10 and no more than 10N. Rotating body 1 with magnetic attraction
When the disk drive device is used in an inverted posture when the disk drive device is in an inverted position below 0, the shaft 1 does not contact the thrust plate 2 because the magnetic attraction force is smaller than the own weight of the rotating member 10, and the rotating member 10 contacts the retaining member 11. Would. 30N magnetic attraction
Above, the axial load applied to the thrust bearing 3 is large, the starting torque is increased, and wear at the time of starting and stopping becomes a problem. When the weight of the rotating body 10 is twice or more, the contact between the shaft 1 and the thrust plate 2 is maintained even if some external impact is applied. When the thickness is set to 10 N or less, the axial load applied to the thrust plate 2 is reduced, so that there is no need to use an expensive material such as ceramic for the thrust plate 2, and there is an advantage that the cost is reduced.

Further, a retaining member 11 is attached to the supporting member 42 to prevent the rotating body 10 from coming off when an impact load is applied during transportation of the motor alone. When the retaining member 11 is attached to the support member 42 so as to engage with the outer peripheral edge of the rotating body 10, the structure of the bearing is simpler and the cost is lower than when a flange is provided on the shaft 1 as in the related art. There is an advantage.

The retaining member 11 is preferably made of a material such as an aluminum alloy, stainless steel, plastic or the like. However, if the retaining member 11 is formed of plastic having excellent self-lubricating properties, the rotating member 10 may be lost during transportation.
However, even if it comes into contact with the retaining member 11, wear damage due to the contact can be reduced.

A circumferential groove 12 is provided on the inner peripheral surface of the rotating body 10 facing the boundary between the upper end surface of the sleeve 6 and the outer diameter surface. Even if the lubricant in the sleeve 6 is scattered by the rotation of the shaft 1 due to the circumferential groove 12, the lubricant is captured in the circumferential groove 12 by the surface tension of the lubricant. Scattering can be prevented.

FIG. 2 shows a second embodiment. In order to increase the magnetic attraction in the axial direction, an auxiliary magnetic attraction mechanism is provided. That is, in the present embodiment, the rotating body 10 has the permanent magnet 14 fixed to the hub 40, and the magnetic body 15 opposed to the permanent magnet 14 via the clearance in the axial direction is fixed to the base 7 to reduce the magnetic attraction in the axial direction. Is occurring. Therefore, the support member 42 has the magnetic body 15. Note that a permanent magnet may be used instead of the magnetic body 15, or a permanent magnet may be fixed to the base 7 by fixing the magnetic body to the hub 40. Further, in this embodiment, as a retaining member for the rotating body 10 with respect to the support member 42, the outer diameter surface of the shaft 1 on the thrust bearing 3 side protrudes in the radial direction, and both side surfaces face the support member 42 via an axial clearance. 2 shows an example in which a projection 16 is provided. With this configuration, even if the projection 16 contacts the support member 42 during rotation due to an external impact, the lubricant is present, so that damage to the projection 16 at the time of contact can be reduced.

FIG. 3 shows a third embodiment. In this example, the rotating body 10 has a sleeve 6, a thrust plate 2 fixed to the sleeve 6, and a hub 40 fixed to the sleeve 6, and the support member 42 is fixed to the shaft 1 fitted to the sleeve 6 and the shaft 1. And a base 7. The rotor 8 fixed to the rotating body 10 and the stator 9 fixed to the support member 42 are axially opposed to each other, and the motor M is a planar opposed motor so that a large magnetic attraction in the axial direction can be set.

In this example, the end surface of the shaft 1 and the thrust bearing surface provided on the thrust plate 2 constitute a planar dynamic pressure thrust bearing 3, and the outer peripheral surface of the shaft 1 and the radial bearing surface 41 of the inner diameter surface of the sleeve. The radial dynamic pressure bearing 4 is configured. The thrust bearing 3 has a groove for generating dynamic pressure on the end face of the shaft 1. The thrust plate 2 which is a mating member is bonded to the sleeve 6 after being caulked to the sleeve 6 in order to prevent leakage of the lubricant.

FIG. 4 shows a fourth embodiment. In this example,
A magnetic body for suction 50 arranged opposite to the lower surface of the rotor 8 of the motor M via an axial clearance is fixed to the base 7,
An axial magnetic attraction is applied between the rotor 8 as a permanent magnet and the magnetic body 50. The magnetic member 50 is a support member 4
Constituting No. 2.

In this embodiment, similarly to the first embodiment, the axial centers of the stator 9 and the rotor 8 are shifted, and an axial magnetic attraction is also applied between the stator 9 and the rotor 8. I have. According to the fourth embodiment, a larger magnetic attraction force can be applied as compared with the first embodiment. When only the magnetic attraction between the rotor 8 and the magnetic body 50 in the axial direction is sufficient, the axial center between the stator 9 and the rotor 8 does not need to be shifted in the axial direction.

According to the fourth embodiment, the axial clearance between the rotor 8 and the magnetic body 50 can be reduced.
Magnetic attraction can be increased. In the case where the axial center of the stator 9 and the axial center of the rotor 8 are shifted in the axial direction as in the first embodiment, if the axial center of the rotor 8 and the stator 9 is shifted too much, the electromagnetic force of the motor may be reduced. There was concern that the sound would be louder, but as a result of experiments, it was not. Further, unlike the second embodiment, there is no need to separately provide a magnet for attraction, which is advantageous in cost.

The magnetization pattern of the rotor 8 may be the same as that of a general motor, but if it is desired to further increase the magnetic attraction force, the lower surface of the rotor 8 should be a magnetization pattern dedicated to attraction. preferable. In this case, if the lower surface of the rotor 8 has concentric magnetized patterns of different polarities such as an N-pole and an S-pole on the inner peripheral portion and the outer peripheral portion, the eddy current generated in the magnetic body 50 can be reduced, and This is more preferable because the loss of M can be reduced.

In the above embodiment, the thrust bearing 3
Since there is no air vent hole between the bearing and the radial dynamic pressure bearing 4, the chamber adjacent to the thrust bearing 3 is in a sealed state and has excellent lubricant retention, so that reliability is ensured even for long-term use. This is preferred because

As the lubricant, a linear fluorine oil having a viscosity index of 300 or more, which has excellent temperature-viscosity characteristics, ie, a small change in viscosity with respect to temperature change, is preferable. In particular, in order to improve the slidability and the retention of the lubricant, a fluoro oil to which a perfluoroalkyl polyether having a carboxylic acid at a terminal is added is preferable.

[0028]

According to the present invention, since the rotating body is supported by the radial dynamic pressure bearing and the thrust bearing constituted by the end face of the shaft, there is an effect that the swing of the non-rotation synchronous component is small and the starting torque is small. . Further, since a predetermined magnetic attraction force is applied in the axial direction, there is an effect that there is no restriction on the use posture. Furthermore, since there is no need to provide a flange portion for receiving an axial load on the shaft, there is an effect that assembly is easy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a disk drive device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a disk drive device according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a disk drive device according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a disk drive device according to a fourth embodiment of the present invention.

FIG. 5 is a diagram for explaining a conventional disk drive device.

FIG. 6 is a diagram for explaining a conventional disk drive.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 21 Shaft 2, 22 Thrust plate 3 Thrust bearing 4 Radial dynamic pressure bearing 5 Holder 6 Sleeve 7, 27 Base 8, 28 Rotor 9, 29 Stator 10, 20 Rotating body 11 Retaining member 12 Peripheral groove 13 Disk 14 Permanent Magnet 15 Magnetic body 16 Projection M, M2 Motor 23 Ball bearing 24 Flange 30 Shaft 40 Hub 41 Radial bearing surface 42 Support member 44 Groove for generating dynamic pressure 50 Magnetic body

Claims (1)

[Claims] 1. A disk drive device in which a rotating body on which a disk can be mounted is driven to rotate by a motor, wherein the rotating body is rotatably supported by a support member via a radial dynamic pressure bearing and a thrust bearing, and the thrust bearing is provided. An axial load is applied by a magnetic attraction force equal to or greater than the weight of the rotating body and equal to or less than 30 N, and one of the rotating body and the support member has a shaft, and an end surface of the shaft constitutes a thrust bearing. A disk drive device.