JP2001084687A - Disk driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a disk driving device which can make a turntable thin without making its characteristics or quality worse. SOLUTION: This disk driving device 10 has its turntable 30 formed of a metal material having properties as a magnetic part and properties as a nonmagnetic part, e.g. stainless steel; and the part 31 of this turntable 30 where an attracting magnet 17 is arranged is formed as a magnetic part and the remaining part 32 is formed as a nonmagnetic part. A back yoke as a discrete body is not necessary and there is no leakage of magnetic noise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive for rotating an information recording disk. More specifically, the present invention relates to a structure of a turntable of a disk drive.

[0002]

2. Description of the Related Art As a disk drive for rotating an information recording disk such as a CD-ROM, a DVD, and an MD, there is one disclosed in, for example, JP-A-8-83466. The disk drive disclosed herein includes:
As shown in FIG.
A turntable 152 for mounting a disk fixed to the rotating shaft 151; an attraction magnet 153 disposed on the turntable; and an attraction magnet 153.
And a back yoke 154 disposed below the back yoke. In this turntable 152, the back yoke 15
4, since the magnetic path is formed, the attraction force is large. Here, the turntable 152 is made of, for example, a synthetic resin, and has an attraction magnet 153 and a back yoke 154.
Are arranged at predetermined positions by insert molding when the turntable 152 is formed.

[0003]

However, in order to reduce the size and thickness of the disk drive, it is necessary to reduce the thickness of the turntable 152 itself. However, in the conventional turntable 152, the attraction magnet 153 is disposed. In the portion, the attraction magnet 153, the back yoke 154, and the bottom wall portion 15 of the turntable 152
7 are overlapped, and it is difficult to reduce the thickness without deteriorating the characteristics and quality. That is, in the conventional turntable 152, when the thickness of the attraction magnet 153 is reduced while keeping the thickness of the back yoke 154 and the bottom wall portion 157, the attraction force is reduced when the turntable 152 is reduced in thickness. Would. Further, when the entire turntable 152 is formed of a magnetic material, the bottom wall portion 157 functions as a back yoke, so that the back yoke 154 can be omitted. Therefore, the turntable 152 can be made thin without making the attraction magnet 153 thin. Can be However, when such a configuration is employed, a magnetic path is formed in the entire turntable 152, and thus a problem such as leakage of magnetic noise occurs.

Further, even if the turntable 152 can be made thinner, if the turntable 152 is made of a synthetic resin, there arises a problem that the surface runout accuracy is reduced. Furthermore, when the turntable 52 is thinned, when the turntable 152 and the rotary shaft 151 are fixed by a method such as press-fitting the rotary shaft 151 into the shaft hole 156 of the turntable 152, the turntable 152 and the rotary shaft 151 are Has a problem in that the verticality of the surface is reduced, and surface deflection occurs.

It is an object of the present invention to provide a disk drive capable of reducing the thickness of the turntable without deteriorating the characteristics and quality of the turntable.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a rotating shaft, a turntable for mounting a disk fixed to the rotating shaft, and an attraction magnet disposed on an upper surface of the turntable. Wherein the turntable is integrally formed of a metal material having a property as a magnetic material and a property as a nonmagnetic material, and a portion of the turntable where the attraction magnet is disposed. Are formed as magnetic portions, and the other portions are formed as non-magnetic portions.

In the present invention, the turntable is made of a metal material, and the portion where the attraction magnet is arranged is formed as a magnetic material portion, and the other portions are formed as non-magnetic material portions. The body part functions as a back yoke as it is. Therefore, there is no need to provide a separate back yoke, so that the turntable can be reduced in thickness without reducing the thickness of the attracting magnet. Even if the turntable is integrally formed of a metal material, magnetic noise leakage does not occur since the portion other than the portion functioning as the back yoke is a non-magnetic material portion. Therefore, it is possible to reduce the thickness of the turntable without deteriorating the characteristics and quality of the turntable.

In the present invention, it is preferable that the turntable is formed by press working from the viewpoint of maximizing the effect of reducing the thickness of the turntable. With this configuration, it is possible to reduce the manufacturing cost of the turntable. In addition, in the case where sufficiently high precision cannot be obtained by press working alone, high precision may be obtained by performing lace processing after press working.

Further, in the present invention, from the viewpoint of making the most of the fact that the turntable is integrally formed of a metal material, the turntable is formed by burning the rotary shaft into a shaft hole of the turntable. Preferably, it is fitted. This shrink fitting method is a method in which a rotary shaft is inserted into a shaft hole in a state where a turntable is heated to expand a shaft hole, and then the turntable is cooled to reduce the shaft hole. Therefore, the shaft hole or the rotating shaft is not deformed as compared with the method of press-fitting the rotating shaft into the shaft hole of the turntable, so that a high perpendicularity can be obtained between the turntable and the rotating shaft. Therefore, even if the turntable is thinned, no run-out occurs.

In the present invention, the turntable includes:
For example, it is formed of stainless steel having properties as a magnetic material and properties as a non-magnetic material.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A disk drive motor to which the present invention is applied will be described with reference to the drawings.

First Embodiment FIG. 1 is a longitudinal sectional view of a disk drive according to the present embodiment.

In FIG. 1, a disk drive device 10 of the present embodiment uses a brushless motor as a motor body, and a rotary shaft is formed by a cylindrical radial bearing 12 and a flat thrust bearing 18 fixed to a base 11. 20 are supported. The radial bearing 12 and the thrust bearing 18 are held inside a cylindrical bearing holder 19, and a stator core 13 is mounted on an outer peripheral side of the bearing holder 19. A drive coil 14 is wound around each salient pole of the steering core 13.

In this embodiment, the upper end portion 2 of the rotating shaft 20
1 is a part 2 supported by a radial bearing 12
2, the upper end portion 2 of this large diameter.
1 is shrink-fit into the shaft hole 33 of the turntable 30,
The turntable 30 is fixed to the rotation shaft 20. In fixing the rotation shafts 20 to each other, a method of press-fitting or bonding the rotation shaft 20 to the shaft hole 33 of the turntable 30 may be employed.

On the upper surface of the turntable 30, a ring-shaped attracting magnet 17 for disk clamping is formed. The attracting magnet 17 is magnetized in the thrust direction. A disk mounting portion 35 for supporting the disk is formed in a ring shape on the outer peripheral side of the upper surface of the turntable 30, and a ring-shaped rubber sheet 36 is affixed thereon.

On the lower surface side of the turntable 30, a cylindrical rotor yoke 37 extends downward from a position corresponding to a position directly below the disk mounting portion 35, and the inner peripheral surface of the rotor yoke 37 faces the stator core 13. The ring-shaped drive magnet 15 is fixed so as to perform the operation. The drive magnet 15 is magnetized in the radial direction.

In this embodiment, the turntable 30 is
The turntable 30 is formed of a metal material having a property as a magnetic material and a property as a non-magnetic material, for example, stainless steel, and a portion 31 of the turntable 30 where the attraction magnet 17 is disposed is formed as a magnetic material portion. The part 32 is formed as a non-magnetic part.

Such a turntable 30 is formed, for example, by pressing non-magnetic stainless steel by press working and then performing laser annealing or high-frequency heating.
After selectively heating the portion 31 on which the attraction magnet 17 is disposed and then naturally cooling, the portion 31 is cooled.
Is selectively made into a metal structure as a magnetic material.

The turntable 30 is, for example, a non-magnetic stainless steel, which is selectively cooled by a method such as laser annealing or high-frequency heating to a portion 31 where the attraction magnet 17 is to be disposed, and then naturally cooled. In this case, the portion 31 may be selectively formed into a metal structure as a magnetic body, and then may be manufactured by press working.

As described above, the disk drive 1 of the present embodiment
0 indicates that the turntable 30 is formed of a metal material, the portion 31 where the attraction magnet 17 is disposed is formed as a magnetic portion, and the other portions 32 are formed as non-magnetic portions. The body part functions as a back yoke as it is. For this reason, since it is not necessary to provide a separate back yoke, the turntable 30 can be reduced in thickness without reducing the thickness of the attraction magnet 17.
If a larger magnetic attraction force is required than to make the turntable 30 thinner, a thicker attracting magnet 17 can be used because the back yoke is omitted. Further, even if the turntable 30 is integrally formed of a metal material, since the portion 32 other than the portion 31 functioning as a back yoke is a non-magnetic material portion, no magnetic noise leakage occurs.
Therefore, the thickness of the turntable 30 can be reduced without deteriorating the characteristics and quality of the turntable 30.

In the present embodiment, the turntable 30 is formed by press working from the viewpoint of maximizing the use of the thinning and uniform thickness of the turntable 30. That is, if the turntable 30 is too thick or the turntable 30 having a large difference in wall thickness, it is difficult to form the turntable 30 by press working. Since the wall thickness can be equalized, it is possible to apply press working with high working efficiency. Therefore, the manufacturing cost of the turntable 30 can be reduced. Also,
If a sufficiently high accuracy cannot be obtained only by pressing, the turntable 30 may be formed by lace after forming the turntable 30 by pressing.

Further, in the present embodiment, the turntable 30
In order to make the best use of being integrally formed from a metal material, the turntable 30 has the rotary shaft 20 shrink-fitted into the shaft hole 33 of the turntable 30. This shrink-fitting technique uses turntable 3
In this method, the rotary shaft 20 is inserted into the shaft hole 33 in a state in which the shaft hole 33 is expanded by heating 0, and then the turntable 30 is cooled to make the shaft hole 33 smaller. Therefore, unlike the method of press-fitting the upper end 21 of the rotating shaft 20 into the shaft hole 33 of the turntable 30, the shaft hole 33 and the rotating shaft 20 of the turntable 30 are not deformed.
A high perpendicularity can be obtained between 0 and the rotation axis 20. Therefore, there is an advantage that even if the turntable 30 is made thinner, surface runout does not occur.

[Second Embodiment] FIG. 2 is a side view showing a part of a disk drive device according to a second embodiment of the present invention. In the disk drive of the present embodiment, the turntable, which is a feature of the present invention, has the same basic configuration as that of the first embodiment. is there.

As shown in FIG. 2, the disk drive device 50 of the present embodiment utilizes a small DC motor with a brush, and a disk drive device (motor device / not shown) for rotating a disk such as an MD. .) Is mounted on a motor mounting section (not shown).

The disk drive device 50 includes a motor body 70 having an output end side of a rotating shaft 60 protruding from an upper end surface 54 of a cup-shaped motor case 51 and a motor case 51 so as to cover the upper end surface 54 of the motor case 51. The mounting plate 80 is fixed by welding or the like.
The mounting plate 80 is a mounting portion of the motor main body 70 to a motor mounting portion of the disk drive device.

A rotating shaft 60 is provided inside the motor case 51.
The armature 55 includes six salient pole cores 56 fixed to a substantially central portion in the axial direction by press fitting or the like and a coil 57 wound around each salient pole core 56. Therefore, the armature 55 rotates integrally with the rotating shaft 60. On the other hand, in the cup-shaped motor case 51,
A four-pole magnetized ring-shaped permanent magnet 53 is fixed to the inner peripheral surface of the side plate portion 52, and each permanent magnet 53 is in a state of facing the outer peripheral surface of the salient pole core 56 via a predetermined gap. .

The rotation shaft 60 has a brush holder 6 at its base end.
The output end is supported by a radial bearing 62 in a rotatable state. A commutator 40 is formed at a lower end portion of the rotating shaft 60, and a varistor (arc-extinguishing element) 49 is mounted at a position adjacent to the commutator 40. The brush 45 held by the brush holder 61 is in contact with the commutator 40.

The radial bearing 62 is not held on the upper end surface 54 of the motor case 51, and a shaft drawing hole 59 is formed in the upper end surface 54 of the motor case 51. Therefore, the output end side of the rotating shaft 60 protrudes upward through the shaft drawing hole 59. The shaft withdrawal hole 59 is formed to be relatively large as a hole for drawing out the output end side of the rotating shaft 60, and is opened at a position overlapping the winding portion of the coil 57 in the motor case 51 in the direction of the motor axis. . That is, the shaft extraction hole 59
The motor case 51 has an opening having an inner diameter slightly larger than the outer diameter of the winding portion of the coil 57 at substantially the center of the upper end surface 54 of the motor case 51. Therefore, the upper end portion of the coil 57 is in a state of directly facing the lower surface of the mounting plate 80 via the shaft drawing hole 59.

In this embodiment, the radial bearing 62 is fixed to a bearing holding hole 81 formed in the center of the mounting plate 80 by a method such as press fitting. This bearing holding hole 81 is
The mounting plate 80 is constituted by a cylindrical portion formed so as to protrude into the motor case 51 by burring processing on a central portion thereof. The radial bearing 62 includes a cylindrical body 63 that holds the rotating shaft 60, and a flange 64 that extends laterally at the upper end of the body 63, and the body 64 is provided with a shaft extraction hole 59 of the motor case 51. And a lower half thereof is located in the motor case 51. The flange portion 64 partially covers the upper surface 82 of the mounting plate 80.

The disk drive 50 thus constructed
The mounting of the motor body 70 on the disk drive device (motor device) is performed by fixing the mounting plate 80 to the motor mounting portion of the disk drive device with a screw or the like, and the motor body 70 is mounted on the motor mounting portion. In this state, the turntable 30 fitted and fixed to the upper end portion of the rotating shaft 60 rotates a disk such as an MD mounted on the upper surface thereof (disk mounting surface 35) around the motor axis.

Also in this embodiment, the turntable 30
Is formed of a metal material having properties as a magnetic substance and properties as a non-magnetic substance, for example, stainless steel,
A part 31 of the turntable 30 where the attraction magnet 17 is disposed is formed as a magnetic part,
The other part 32 is formed as a non-magnetic part.

The turntable 30 is formed, for example, by pressing a non-magnetic stainless steel by pressing, and then performing laser annealing or high-frequency heating.
After selectively heating the portion 31 on which the attraction magnet 17 is disposed and then naturally cooling, the portion 31 is cooled.
Is selectively made into a metal structure as a magnetic material.

The turntable 30 is, for example, a non-magnetic stainless steel, which is selectively cooled by a method such as laser annealing or high-frequency heating to a portion 31 where the attraction magnet 17 is to be disposed, and then naturally cooled. In this case, the portion 31 may be selectively formed into a metal structure as a magnetic body, and then may be manufactured by press working.

As described above, the disk drive 1 of the present embodiment
0 indicates that the turntable 30 is formed of a metal material, the portion 31 where the attraction magnet 17 is disposed is formed as a magnetic portion, and the other portions 32 are formed as non-magnetic portions. The body part functions as a back yoke as it is. For this reason, since it is not necessary to provide a separate back yoke, the turntable 30 can be reduced in thickness without reducing the thickness of the attraction magnet 17.
Further, even if the turntable is integrally formed of a metal material, since the portion 32 other than the portion 31 functioning as the back yoke is a non-magnetic material portion, no magnetic noise leakage occurs. Therefore, the turntable 30
The same effects as in the first embodiment can be obtained, for example, the thickness of the turntable 30 can be reduced without deteriorating the characteristics and quality of the turntable.

In this embodiment, the turntable 30
Although the thickness and the shape of this are different from those of the first embodiment, also in this embodiment, since the turntable 30 is thin, it can be formed by press working. Therefore, the turntable 30
Manufacturing cost can be reduced.

Further, also in the present embodiment, from the viewpoint of making the most of the fact that the turntable 30 is integrally formed of a metal material, the turntable 30 is provided with the rotating shaft 60 in the shaft hole 33 of the turntable 30. Is shrink-fitted. Therefore, the shaft hole 33 of the turntable 30
Unlike the method of press-fitting the upper end portion 21 of the rotating shaft 20, the shaft hole 33 and the rotating shaft 20 are not distorted, so that a high degree of perpendicularity between the turntable 30 and the rotating shaft 20 can be obtained. Therefore, even if the turntable 30 is made thinner, no run-out occurs.

To rotate the disk horizontally,
The rotation shaft 60 is required to be perpendicular to the motor mounting portion. Here, in this embodiment, the burring process for forming the bearing holding hole 81 in the mounting plate 80 is performed such that the center axis of the bearing holding hole 81 is perpendicular to the mounting plate 80. In this way, if the bearing holding holes 81 are formed at right angles with the mounting plate 80 as a reference plane, the mounting plate 8
Since the radial bearing 62 can be fixed at a right angle to 0,
The perpendicularity between the mounting plate 80 and the rotating shaft 60 can be easily obtained.

[Other Embodiments] In the above embodiment, the stainless steel constituting the turntable 30 is selectively heat-treated to partially form the magnetic material 31. By shaping the turntable 30 while changing the compounding ratio, the portion 31 where the attraction magnet 31 is disposed may be made of a magnetic material, and the other portions 32 may be made of a non-magnetic material.

[0039]

As described above, in the disk drive according to the present invention, the turntable is formed of a metal material, the portion where the attraction magnet is disposed is formed as a magnetic material portion, and the other portions are formed. Is formed as a non-magnetic part, the magnetic part functions as a back yoke as it is. Therefore, there is no need to provide a separate back yoke, so that the turntable can be reduced in thickness without reducing the thickness of the attracting magnet. Even if the turntable is integrally formed of a metal material, magnetic noise leakage does not occur since the portion other than the portion functioning as the back yoke is a non-magnetic material portion.
Therefore, without deteriorating the characteristics and quality of the turntable,
The turntable can be made thinner.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a disk drive device according to Embodiment 1 of the present invention.

FIG. 2 is a side view showing a part of a disk drive device according to a second embodiment of the present invention, with a portion cut away;

FIG. 3 is an explanatory diagram of a conventional disk drive device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10, 50 Disk drive device 11 Base 12 Radial bearing 13 Stator core 14 Drive coil 15 Drive magnet 17 Attraction magnet 18 Thrust bearing 20, 60 Rotating shaft 21 Upper end portion of rotating shaft 30 Turntable 33 Shaft hole 35 Disk mounting portion 36 Rubber sheet 40 Commutator 45 Brush 59 Shaft extraction hole 51 Motor case 53 Permanent magnet 55 Armature 56 Salient pole core 57 Coil 61 Brush holder 62 Radial bearing 68 Thrust bearing 70 Motor body 80 Mounting plate

Claims (4)

[Claims] 1. A disk drive having a rotating shaft, a turntable for mounting a disk fixed to the rotating shaft, and an attraction magnet disposed on an upper surface of the turntable, wherein the turntable is a magnetic material. The turntable is formed integrally from a metal material having properties as a non-magnetic material, and a portion of the turntable where the attraction magnet is disposed is formed as a magnetic material portion, and other portions are non-magnetic materials. A disk drive device formed as a part. 2. The disk drive according to claim 1, wherein the turntable is formed by press working. 3. The disk drive according to claim 1, wherein the turntable is formed by shrink-fitting the rotary shaft into a shaft hole of the turntable. 4. The method according to claim 1, wherein
The disk drive device, wherein the turntable is made of stainless steel having properties as a magnetic material and properties as a non-magnetic material.