JPH05101524A - Hard disk device - Google Patents

Abstract

PURPOSE:To additionally reduce the size and thickness of the above device without contaminating the inside of a disk chamber by a lubricating oil, etc., and to additionally reduce the thickness while sufficiently attaining the rotating accuracy of a hard disk. CONSTITUTION:A hard disk 18 is fixed by diffusion joining to a rotor hub 32. Since a clamping member is not used, the size in the axial line direction is shortened. The revolving shaft 34 of the rotor hub 3 made of a ferromagnetic material is housed into a bearing member 30. A permanent magnet body 42 is fixed to the top end face of the bearing member 30. The revolving shaft 34 is stably supported inward in a diametral direction by the dynamic pressure acting on a band-shaped part 38 when the revolving shaft 34 revolves. The revolving shaft 34 is stably supported in the axial line direction by the balance between the dynamic pressure acting on a curved end face part 36 and the magnetic attraction force that the permanent magnet body 42 exerts on the rotor hub 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard disk drive for driving a hard disk by a spindle motor.

[0002]

2. Description of the Related Art Demands for thinning and downsizing of computer devices such as notebook personal computers are becoming more and more strict, and various computers are required to meet such demands. The hard disk device used in the device is also required to be thinner and smaller.

However, in order to prevent the lubricating oil and the like of the bearings from being scattered into the disk chamber of the hard disk device to contaminate the hard disk and cause a read / write error, the inside and outside of the spindle motor in the disk chamber are sealed with a magnetic fluid seal or a magnetic fluid seal. It is necessary to seal as much as possible with a sealing means such as a labyrinth seal, and the space of such sealing means is one factor that prevents further miniaturization and thinning of the hard disk drive spindle motor and the entire hard disk drive. Is becoming

When the hard disk is fixed to the rotor frame of the spindle motor, various clamp members are used to clamp the hard disk between the rotor frame and the rotor frame. However, such conventional clamp members can be used. This is a factor that prevents further thinning of hard disk devices.

The present invention has been made in view of the above problems existing in the prior art, and its object is to prevent the inside of the disk chamber from being contaminated by lubricating oil or the like. An object of the present invention is to provide a hard disk device that can be further reduced in size and thickness, and a hard disk device that can be further thinned while achieving sufficient rotation accuracy of the hard disk.

[0006]

In order to achieve the above object, a hard disk device of the present invention is a hard disk having a hard disk drive spindle motor in which a rotor shaft protruding from a rotor frame is rotatably supported. In the device, the rotating shaft is housed in a bearing hole at one end opening, and the gas in the disk chamber is used as a lubricant to make the circumferential surface portion and the end surface portion of the rotating shaft inward in the radial direction and in the axial direction of the bearing hole opening. The rotary shaft is stably supported in the radial direction and the axial direction by the dynamic pressure gas bearing portion that is supported by and the magnetic means that applies a magnetic force in the axial direction toward the inner side of the bearing hole to the rotor frame.

Further, the hard disk device of the present invention is a hard disk device in which a hard disk is fixedly held on a rotor frame of a spindle motor, and the rotor frame and the hard disk made of the same kind or different kinds of metal are diffused without using a clamp member. It is assumed to be fixed by joining.

[0008]

According to the first aspect of the invention, the rotary shaft is stably supported radially inward by the dynamic pressure gas bearing portion, and the rotary shaft is supported by the dynamic pressure gas bearing portion in the axial direction toward the bearing hole opening. At the same time, a magnetic force in the opposite direction acts on the rotor frame by the magnetic means, so that the rotating shaft is stably supported in the axial direction. The dynamic pressure gas bearing is
Since the gas in the disc chamber is used as a lubricant, the disc chamber is not contaminated by lubricating oil or the like.

According to the second aspect of the invention, the hard disk is fixed to the rotor frame by diffusion bonding, and no clamp member is used. Therefore, the dimension in the axial direction can be shortened. Further, since the deformation caused by the diffusion bonding is small, it is possible to prevent the accuracy of fixing the hard disk from being impaired.

[0010]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of a hard disk device as one embodiment of the present invention.

Reference numeral 10 denotes a base of the disk chamber 12 in the hard disk device, which has a box shape. 14
Is a lid of the disk chamber, 16 is a spindle motor, and 18 is a hard disk. Air is normally used as the gas in the disk chamber 12, but it is also possible to use, for example, an inert gas.

At the center of the base 10, a cylindrical projection 20 is provided integrally with the base 10 so as to project inside the disk chamber 12, that is, upward in FIG. The cross-section of the cylindrical protrusion 20 has a C-shape having a cutout portion 22 in a part thereof. Reference numeral 24 denotes a stator core fixed to the outer peripheral portion of the cylindrical protrusion 20, and 26 denotes the stator core 24.
The stator coil is wound around.

Inside the cylindrical protrusion 20, there is a bearing hole 2 having a U-shaped vertical cross-section which opens upward in FIG.
A bearing member 30 having a columnar outer shape having 8 is fixed, and the inside and outside of the disk chamber 12 are sealed. 32 is
A rotor hub (rotor frame) 34 made of an iron-based material and having a cup shape with a downward opening is a rotary shaft that is provided so as to project inward at the center of the base portion 35 of the rotor hub 32. The rotary shaft 34 has a U-shaped vertical cross section and is housed in the bearing hole 28.

Spiral grooves are evenly provided on the curved end surface portion 36 of the rotary shaft 34, and a small amount of an axial line from the curved end surface portion 36 of the peripheral surface portion housed in the bearing hole 28 of the rotary shaft 34 is provided. Herringbone-shaped grooves are evenly provided in the strip-shaped portion 38 spaced apart in the direction distance. Bearing member 30
On the other hand, when the rotating shaft 34 rotates, the pressure of air between the inner surface of the bearing hole 28 and the outer surface of the rotating shaft 34 is positively increased to generate a sufficient supporting force. It goes without saying that the shape and size of these grooves can be selected as appropriate. ,

Reference numeral 40 denotes the outer peripheral portion of the bearing member 30 and the bearing hole 2.
8 is a small-diameter communicating hole that communicates with 8. This communication hole 40
On the side of the bearing hole 28, is opened at a position of a flat peripheral surface portion between the curved end surface portion 36 and the band-shaped portion 38 of the accommodated rotating shaft 34, and the outer peripheral portion of the bearing member 30 is a cylindrical protrusion. 20
Is communicated with the disk chamber 12 through the notch 22 in the above, and when the rotating shaft 34 rotates, it is possible to supply air between the outer surface of the rotating shaft 34 and the inner surface of the bearing hole 28. ..

An annular permanent magnet body 42 having an inner diameter larger than that of the bearing hole 28 is fixed to the upper end surface of the bearing member 30 which is arranged inside the cylindrical projection 20 and is lower than the cylindrical projection 20. ing. The permanent magnet body 42 is magnetized in the axial direction, and the base portion 3 of the rotor hub 32 is magnetized.
A suction force in the axial direction is applied to the rotor hub 32 with a slight gap from the lower surface of the rotor hub 5.

An annular rotor magnet 46 is fixed to the outer peripheral lower end portion of the rotor hub 32, that is, the inner peripheral surface of the opening 44. The rotor magnet 46 and the stator core 24 are disposed on the outer peripheral side with a radial gap therebetween. Are facing each other. The rotor hub 32 in this embodiment also serves as the yoke of the rotor magnet 46.

The base portion 35 of the rotor hub 32 has a circular upper end surface 35a and an annular surface 3 provided at the outer periphery of the base surface 35 so as to be lowered by one step.
5b. The hard disk 18 is made of an aluminum alloy and has a lower surface 1 on the inner peripheral portion of the hard disk 18.
8a is gold (Au) plated and then fixed by diffusion bonding to an indium (In) plated annular surface 35b. Since the deformation caused by the diffusion bonding is small, the fixing accuracy of the hard disk 18 is prevented from being impaired.

Diffusion bonding is performed as follows, for example.
The inner peripheral lower surface 18a of the hard disk 18 and the annular surface 35b of the rotor hub 32, which are joint surfaces, are smoothed and cleaned. Under the vacuum atmosphere, the annular surface 35 of the rotor hub 32 is
b and the lower surface of the inner peripheral portion of the hard disk 18 are brought into contact with each other, and a small pressure that causes microscopic plastic deformation on the surface irregularities is applied. This destroys the surface layer such as oxide film,
The true contact of the metal surface increases. At the same time, if the hard disk 18 and the rotor hub 32 are heated to such an extent that they are not adversely affected so that the plastic deformation of the surface is promoted by the creep deformation, the required pressing force is reduced. When the pressure and temperature are maintained for a certain period of time, the voids in the joint become spherical and disappear due to diffusion.

In the case of this embodiment, the gold plating film on the lower surface 18a of the inner peripheral portion of the hard disk 18 and the rotor hub 32 are arranged.
When the indium-plated film on the annular surface 35b is adhered and heated, diffusion starts at around 100 ° C. Therefore, it is possible to process and bond at a temperature extremely lower than the melting temperature of each metal, and inconveniences such as shape deformation of the hard disk 18 and the rotor hub 32 due to high temperature heating are avoided.

When the rotating shaft 34 is rotated by the operation of the spindle motor 16, the rotating shaft 3 is mainly caused by the dynamic pressure generated in the air between the strip portion 38 and the inner peripheral surface of the bearing hole 28.
4 is stably supported inward in the radial direction, and by the dynamic pressure generated between the curved end surface portion 36 and the curved bottom surface portion of the bearing hole 28,
The rotary shaft 34 is supported axially upward. The supporting force in the axial direction upward is generated when the permanent magnet body 42 is rotated by the rotor hub 32.
Is maintained in balance with the downward magnetic attraction force exerted on the rotary shaft 34, and the rotary shaft 34 is stably supported in the axial direction. Since the rotation shaft 34 is supported by the dynamic pressure air bearing using the air in the disk chamber 12 as a lubricant and the magnetic force of the permanent magnet body 42, the inside of the disk chamber 12 is contaminated by lubricating oil or the like. There is no noise and the noise is low. Further, since it is not necessary to seal the inside and outside of the spindle motor 16, it is possible to make the device thinner and smaller.

Further, the hard disk 18 is the rotor hub 3.
Since it is fixed by diffusion bonding to No. 2 and no clamp member or the like is used, the dimension in the axial direction is shortened by that amount.

In the above embodiment, the combination of the permanent magnet body 42 provided on the upper end surface of the bearing member 30 and the rotor hub 32 made of iron-based material is used as the magnetic means, but the position of the permanent magnet body is changed. The provision of a member made of a ferromagnetic material on the rotor hub made of a non-ferromagnetic material, the provision of a permanent magnet body on the rotor hub side, and the like can be appropriately performed as necessary.

[0024]

According to the hard disk drive of the first aspect, the inside of the disk is not contaminated by the lubricating oil or the like. Therefore, it is not necessary to use a sealing means, and the space can be saved accordingly. Further, since the axial stability is achieved by the balance between the supporting force in the axial direction of the bearing hole opening with respect to the end surface of the rotating shaft and the magnetic force of the magnetic means in the bearing hole inward direction with respect to the rotor frame, the magnetic force It is possible to reduce the dimension in the axial direction as compared with the case where the axial stability is achieved only by acting on the rotating shaft. Therefore, it is possible to further reduce the size and thickness.

In the hard disk device according to the second aspect, it is possible to prevent the fixing accuracy of the hard disk from being impaired by the diffusion bonding, so that the rotation accuracy of the hard disk fixed to the rotor frame and rotating can be sufficiently achieved. Further, since the clamp member is not used, the dimension in the axial direction can be shortened by that amount, and the thickness can be further reduced.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a hard disk device.

[Explanation of sign]

 12 disk chamber 16 spindle motor 18 hard disk 18a inner peripheral lower surface 28 bearing hole 30 bearing member 32 rotor hub 34 rotating shaft 35b annular surface 36 curved end surface 38 strip portion 42 permanent magnet body

Claims (2)

[Claims] 1. A hard disk device comprising a spindle motor for driving a hard disk, wherein a rotary shaft projecting from a rotor frame is rotatably supported, wherein the rotary shaft is housed in a bearing hole at one end of the disk. A dynamic gas bearing that uses the gas in the room as a lubricant to support the circumferential surface and the end surface of the rotating shaft inwardly in the radial direction and in the direction of the bearing hole opening in the axial direction, and the magnetic bearing in the axial direction toward the back of the bearing hole. A hard disk device, wherein the rotating shaft is stably supported in a radial direction and an axial direction by a magnetic unit that applies a force to a rotor frame. 2. A hard disk device in which a hard disk is fixedly held on a rotor frame of a spindle motor, wherein the rotor frame and the hard disk made of the same or different metals are fixed by diffusion bonding without using a clamp member. A hard disk device characterized by the above.