JP2001084684A - Disk driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a disk driving device which can be made small-sized and thin without deteriorating characteristics nor quality by constituting the periphery of a rotary shaft with high size precision. SOLUTION: This disk driving device 10 has a turntable 30 fixed through a hub fixing piece 90 on the upper-end side of the rotary shaft 20. This hub fixing piece 90 has a cylinder part 91 where the upper-end part of the rotary shaft 20 is fitted and a hub guide part 92 which is fitted in the center hole of a disk hub to guide the hub. The hub fixing piece 90 has a larger outer diameter than the rotary shaft 20 and is equal in hardness to or less than that of the rotary shaft 20.

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 on the tip side of a rotating shaft for guiding a hub of a disk in a disk drive.

[0002]

2. Description of the Related Art Disk drives for rotating recording disks such as CD-ROMs, DVDs, and MDs include:
A chucking mechanism for holding these disks is formed. As a disk drive device provided with this chucking mechanism, for example, one disclosed in Japanese Patent Publication No. 7-85327, as shown in FIG.
There are formed 50 rotary shafts 151, a disc mounting turntable 152 fixed to the rotary shaft 151, and an attracting magnet 153 arranged on the turntable. Here, the rotary shaft 151 is a round bar having a constant outer diameter in the longitudinal direction, and
Inside, it is rotatably supported by a radial bearing 155 such as a bearing.

[0003] The turntable 152 constructed as described above.
When the disk 200 is mounted on the disk 200, the taper 156 is formed at the distal end of the rotating shaft 151, and the distal end enters the central hole 202 of the disk hub 201 of the disk 200 as the hub guide 158, thereby forming the disk hub. Guide 201 At this time, since the attracting magnet 153 attracts the disk hub 201, when the turntable 152 rotates, the disk 200 rotates without slipping.

[0004]

However, there is a demand for a disk drive device to be smaller and thinner, as well as to have higher accuracy, higher speed, and lower power consumption of the motor.
The conventional structure cannot meet such a demand for miniaturization and thinning. That is, in order to reduce the size and thickness of the disk drive device, it is necessary to make a design change such as reducing the diameter of the rotating shaft 151 and shortening the fixed span between the rotating shaft 151 and the turntable 152. If a design change is made, the required accuracy cannot be obtained by securing the conventional dimensional accuracy or dimensional accuracy by secondary processing, and there is a problem that the runout of the turntable 152 occurs.

[0005] Further, since the tip of the rotary shaft 151 is a hub guide 158, the outer diameter of the tip cannot be changed.
The part held by the radial bearing 155 inside the
Since the size of the motor main body 150 is naturally determined, the size of the motor cannot be reduced with the round shaft 151.

Therefore, as shown in FIG. 7, it is conceivable to use a stepped rotary shaft 161 whose outer diameter is changed in the longitudinal direction. In the stepped rotary shaft 161, the distal end side is the hub guide portion 15 for the disk hub 201 shown in FIG.
8, the outer diameter of the base 159 of the rotary shaft 161 is adjusted to the size of the small radial bearing 155. However, for the rotating shaft 161, high dimensional accuracy is required on both the hub guide portion 158 and the base end side 159. However, such a stepped rotating shaft 161 can be manufactured with high dimensional accuracy. There is a problem that can not be.

In view of the above, the present invention provides a disk drive capable of achieving a reduction in size and thickness without deteriorating characteristics and quality by adopting a structure that can be configured with high dimensional accuracy around the rotation shaft. To provide.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a rotating shaft, a radial bearing which forms a sliding portion with an outer peripheral surface of the rotating shaft and rotatably supports the rotating shaft. A turntable for mounting a disc fixed to the rotating shaft, and a hub guide portion is formed at a distal end side of the rotating shaft to enter a central hole formed in a hub of the disc and guide the hub. The rotating shaft and the turntable are fixed via a hub fixing piece formed with a cylindrical portion into which the rotating shaft is fitted and the hub guide portion. Is characterized by having an outer diameter dimension larger than the outer diameter dimension of the rotating shaft, and having a hardness equal to or less than the hardness of the rotating shaft.

In the present invention, the radial bearing is not a bearing having a large outer diameter, such as a ball bearing, but a radial bearing.
A small and thin disk drive is achieved by using a small-diameter bearing that forms the outer peripheral surface and the sliding surface of the rotating shaft and using a small-diameter rotating shaft. Also,
Since the rotating shaft and the turntable are fixed to each other through a hub fixing piece separate from the rotating shaft, and the hub fixing piece is used for guiding the hub of the disk, even if the diameter of the rotating shaft is reduced, the hub fixing piece may be used. Can be formed to have an outer diameter dimension that can guide a central hole formed in the hub of the disk. Furthermore, even if the rotating shaft has a small diameter, the turntable is fixed to the hub fixing piece having the same thickness as the conventional one, so that the runout is not inferior to that of the conventional product. Furthermore, since the hub fixing piece has a hardness equal to or less than that of the rotating shaft, the rotating shaft is not distorted by the stress when the rotating shaft is fitted inside the hub fixing piece. Furthermore, since the rotating shaft and the hub fixing piece having different outer diameters are made as separate parts, they are manufactured as parts having the same outer diameter in the length direction, so that the rotating shaft and the hub fixing piece are each higher. Can be manufactured with dimensional accuracy.

In the present invention, there is a case where a rotor yoke is fixed to the turntable, and a driving magnet facing the stator core is formed on the rotor yoke.

In the present invention, the difference between the outer diameters of the hub fixing piece and the rotating shaft is preferably in a range from 0.4 mm to 1.5 mm. 0.4m difference in outer diameter
When the diameter is less than m, there is no great advantage as compared with the case where the round rod-shaped rotating shaft is used as it is. When the diameter of the rotating shaft is made smaller as the difference exceeds 1.5 mm, the surface runout tends to increase.

In the present invention, when the turntable is made of metal having a shaft hole in the center, the hub fixing piece can be press-fitted into the shaft hole. With this configuration, the fixing strength between the turntable and the hub fixing piece is large.

In the present invention, when the turntable is made of metal having a shaft hole in the center, it is preferable that the hub fixing piece is shrink-fitted and fixed in the shaft hole. This shrink fitting method is a method in which a hub fixing piece 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, since the shaft hole or the hub fixing piece is not deformed as compared with the method of press-fitting the hub fixing piece into the shaft hole of the turntable, a high verticality can be obtained between the turntable and the rotating shaft. . Therefore, no run-out occurs on the turntable.

In the present invention, when the turntable is a resin molded product, the hub fixing piece having a groove formed on an outer peripheral side face may be fixed at the center of the turntable by outsert molding.

[0015]

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 has a cylindrical radial bearing 12 and a flat plate-like shape held on a base 11 via a bearing holder 19. The rotating shaft 20 is supported by the thrust bearing 18. The stator core 13 is mounted on the outer peripheral side of the bearing holder 19. A drive coil 14 is wound around each salient pole of the steering core 13.

In the present embodiment, the radial bearing 12 is not of a large diameter such as a ball bearing but is of a small diameter such as a sintered oil-impregnated bearing.
The sliding shaft 28 is formed at two places separated from each other in the thrust direction to support the rotating shaft 20 rotatably around its axis.

In this embodiment, a turntable 30 is fixed to the upper end side of the rotating shaft 20, and a ring-shaped suction magnet 17 for disk clamp is formed on the upper surface of the turntable 30. 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. In this embodiment,
The turntable 30 is made of a metal having a property as a magnetic material. In the turntable 30, the bottom wall 31 below the attraction magnet 17 functions as a back yoke.

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 an 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 not directly fixed on the upper end side of the rotating shaft 20 but is fixed via a cap-shaped hub fixing piece 90 fixed on the upper end side of the rotating shaft 20. Have been. This hub fixing piece 9
Reference numeral 0 denotes a cylindrical portion 91 into which the upper end portion of the rotating shaft 20 fits, and a hub guide portion 92 which fits into the central hole 202 of the hub 201 of the disk 200 described with reference to FIG. Is formed. That is, a portion corresponding to the hub guide portion 92 in the upper end portion of the hub fixing piece 90 has a conical tapered surface.

Here, the hub fixing piece 90 has the rotating shaft 20 fitted and fixed inside the cylindrical portion 91, and
By being fitted in the shaft hole 33 formed in the center of the turntable 30, the turntable 30 is
The upper end is fixed.

Here, the outer diameter of the hub fixing piece 90 is larger than that of the rotary shaft 20. For example, when the outer diameter of the rotary shaft 20 is ΦE and the outer diameter of the hub fixing piece 90 is ΦD, there is a relation of the following equation: ΦD−ΦE = 0.4 mm to 1.5 mm.

The hardness of the hub fixing piece 90 depends on the rotation axis 2.
Equal to or less than 0 hardness. Here, the rotating shaft 2
When the hub fixing pieces 90 having a hardness equal to 0 are used, the same material, for example, S
US420 may be used. On the other hand, the rotating shaft 20
When using the hub fixing piece 90 having a lower hardness than the SUS 420 (hardness = 550)
Hv), and the hub fixing piece 90 is SUS304
(Hardness = 350 Hv) may be used.

The disk drive 10 constructed as described above
When manufacturing the hub, first, the upper end portion of the rotating shaft 20 is pressed into the cylindrical portion 91 of the hub fixing piece 90. Even when such press-fitting is performed, the hardness of the hub fixing piece 90 is not
Since the hardness is equal to or lower than 0, the rotating shaft 20 is not deformed.

Next, the turntable 30 is fixed to the rotating shaft 20 using the hub fixing piece 90 fixed to the rotating shaft 20. At this time, for example, the hub fixing piece 90 fixed to the rotating shaft 20 is press-fitted into the shaft hole 33 of the turntable 30. If such a press fit method is adopted,
The turntable 30 and the hub fixing piece 90 can be fixed with high strength.

When fixing the turntable 30 to the hub fixing piece 90, the hub fixing piece 90 may be shrink-fitted into the shaft hole 33 of the turntable 30 and fixed. This shrink-fitting method heats the turntable 30 and turns the shaft hole 3
3, the hub fixing piece 90 is inserted into the shaft hole 33, and then the turntable 30 is cooled and
Is a way to reduce Therefore, the turntable 30
As compared with the method of press-fitting the hub fixing piece 90 into the shaft hole 33, the shaft hole 33 or the hub fixing piece 90 is not deformed, so that a high verticality is obtained between the turntable 30 and the rotating shaft 20. Can be. Therefore, the turntable 30
No runout occurs on the surface.

After the hub fixing piece 90 is fixed to the shaft hole 33 of the turntable 30, the rotary shaft 20 may be press-fitted and fixed to the hub fixing piece 90.

As described above, the disk drive 1 of the present embodiment
0, the radial bearing 12 is not a large-diameter bearing such as a ball bearing, but a small-diameter bearing that forms the outer peripheral surface of the rotating shaft 20 and the sliding surface 28. By using the disk drive, the size and thickness of the disk drive device 10 are reduced. Further, the rotating shaft 20 and the turntable 30 are fixed via the hub fixing piece 90 separate from the rotating shaft 20, and
Since the hub fixing piece 90 is used for guiding the hub of the disk (see FIG. 6), even if the diameter of the rotating shaft 20 is reduced, the hub fixing piece 90 has a central hole 202 formed in the hub 201 of the disk 200. Can be formed in an outer diameter dimension that can guide the outer diameter. Further, even if the rotating shaft 20 has a small diameter, the turntable 30 is fixed to the hub fixing piece 90 having the same thickness as the conventional one, so that the runout is the same as that of the conventional product. Further, since the hub fixing piece 90 has a hardness equal to or less than that of the rotating shaft 20, the rotating shaft 20 is distorted by stress when the rotating shaft 20 is fitted inside the hub fixing piece 90. There is no. Furthermore, since the rotating shaft 20 and the hub fixing piece 90 having different outer diameters are made as separate parts, they are manufactured as parts having the same outer diameter in the length direction. 90 can be manufactured with high dimensional accuracy.

The disk drive 10 constructed as described above
The results of evaluating the structure around the rotation axis 20 and the degree of surface runout will be described with reference to FIG.

FIG. 2 shows each sample No. 1 to No. 5 shows the results of measuring and evaluating the degree of surface runout.

Of the materials shown here, sample no. 1 is
This is a comparative example using a straight rotating shaft as shown in FIG. Sample No. 2 is a comparative example in which a rotating shaft having a stepped structure is integrally formed as shown in FIG.

Sample No. 3, the hub fixing piece 90 is fixed to the straight rotating shaft 20 as shown in FIG. 1, and the difference between the outer diameters of the hub fixing piece 90 and the rotating shaft 20 is 0.4 mm.
It is an Example of the present invention set to.

Sample No. 4, the hub fixing piece 90 is fixed to the straight rotating shaft 20 as shown in FIG. 1, and the difference between the outer diameters of the hub fixing piece 90 and the rotating shaft 20 is 1.0 mm.
It is an Example of the present invention set to.

Sample No. 5, the hub fixing piece 90 is fixed to the straight rotating shaft 20 as shown in FIG. 1, and the difference between the outer diameters of the hub fixing piece 90 and the rotating shaft 20 is 1.6 mm.
It is an Example of the present invention set to.

As shown in FIG. 2, the sample No. corresponding to the embodiment of the present invention. Samples Nos. 3 and 4 have almost the same characteristics as those using a conventional straight round bar (Sample No. 1). That is, when the hub fixing piece 90 is fixed to the rotating shaft 20 as shown in FIG. 1 and the difference between the outer diameters of the hub fixing piece 90 and the rotating shaft 20 is 0.4 mm to 1.5 mm, the turntable 30 This is an acceptable level even if surface runout does not occur.

The sample N corresponding to the embodiment of the present invention
o. Sample No. 5 is slightly inferior to the one using a conventional straight round bar (Sample No. 1), but at a practically acceptable level.

On the other hand, as shown in FIG. 7, when the rotating shaft having the stepped structure is integrally formed (sample No. 2), the conventional dimensional accuracy at the time of forming the rotating shaft causes a variation in the conventional structure. Using a straight round bar (Sample No.
It can be seen that the runout is larger than that of 1).

[First Modification of First Embodiment] FIG. 3 is a half sectional view of a disk drive device according to the present embodiment. The disk drive according to the present embodiment has a basic structure shown in FIG.
Therefore, the corresponding parts are denoted by the same reference numerals, and only the characteristic parts will be described.

Referring to FIG. 3, the disk drive device 10 of this embodiment also uses a brushless motor as a motor body, and has a cylindrical radial bearing 12 and a flat plate-like shape held on a base 11 via a bearing holder 19. The rotating shaft 20 is supported by the thrust bearing 18. In this embodiment, the disk drive device 10 is made thinner, for example, a thinner bearing holder 19 is used. The stator core 13 is provided on the outer peripheral side of the bearing holder 19.
Are mounted, and a driving coil 14 is wound around each salient pole of the steering core 13.

Also in this embodiment, the radial bearing 12 is not a large diameter such as a ball bearing but a small diameter such as a sintered oil-impregnated bearing, and a sliding surface 28 is formed between the radial bearing 12 and the rotating shaft 20. In this state, the rotating shaft 20 is supported so as to be rotatable around its axis.

In this embodiment, the turntable 30 is fixed to the upper end side of the rotating shaft 20. However, the turntable 30 is not directly fixed to the rotating shaft 20, but is the same as in the first embodiment. Are fixed via a cap-shaped hub fixing piece 90 fixed to the upper end side of the rotating shaft 20. The hub fixing piece 90 includes a cylindrical portion 91 into which the upper end portion of the rotating shaft 20 fits, and the disk 2 described with reference to FIG.
This hub 2 fits into the central hole 202 of the hub 201
And a hub guide portion 92 for guiding the first guide member 01.

In this embodiment, the upper end of the rotating shaft 20 is fitted deeply into the hub fixing piece 90, and the disk drive 1
0 is made thinner.

The hub fixing piece 90 fixed to the rotating shaft 20 is provided with a shaft hole 3 formed in the center of the turntable 30.
3, the turntable 30 is fixed to the upper end portion of the rotating shaft 20.

Also in this embodiment, the outer diameter of the rotary shaft 20 is Φ
E, when the outer diameter of the hub fixing piece 90 is ΦD, the following equation ΦD−ΦE = 0.4 mm to 1.5 mm, and the hardness of the hub fixing piece 90 is the hardness of the rotating shaft 20. Equal to or lower. Other configurations are the same as those of the first embodiment, and corresponding parts are denoted by the same reference numerals in FIG. 3 and description thereof will be omitted.

The disk drive 10 constructed as described above
In the manufacture of the base plate, press-fitting is used for fixing the turntable 30 to the hub fixing piece 90 and for fixing the rotating shaft 20 to the hub fixing piece 90. In addition, shrink fitting may be employed for fixing the hub fixing piece 90 and the turntable 30.

The disk drive 10 constructed as described above
Also, the rotation shaft 20 and the turntable 30 are fixed via the rotation shaft 20 and the separate hub fixing piece 90, and
Since the hub fixing piece 90 is used for guiding the hub of the disk (see FIG. 6), even if the diameter of the rotating shaft 20 is reduced, the hub fixing piece 90 has a central hole 202 formed in the hub 201 of the disk 200. The same effects as in the first embodiment can be obtained, for example, the outer diameter can be formed so as to be able to be guided.

[Modification 2 of Embodiment 1] FIG. 4 is a longitudinal sectional view of a disk drive device according to this embodiment. The disk drive according to the present embodiment also has a basic structure shown in FIG.
Therefore, the corresponding parts are denoted by the same reference numerals, and only the characteristic parts will be described.

In FIG. 4, even in the disk drive device 10 according to the present embodiment, the turntable 3
0 is fixed, and a ring-shaped suction magnet 17 for disk clamp is formed on the upper surface of the turntable 30. 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.

In this embodiment, since the turntable 30 is made of a synthetic resin, the back yoke 32 is disposed below the attraction magnet 17.

Also in the present embodiment, the turntable 30 is not directly fixed on the upper end side of the rotating shaft 20, but via a cap-shaped hub fixing piece 90 fixed on the upper end side of the rotating shaft 20. Fixed. This hub fixing piece 9
Reference numeral 0 denotes a cylindrical portion 91 into which the upper end portion of the rotating shaft 20 fits, and a hub guide portion 92 which fits into the central hole 202 of the hub 201 of the disk 200 described with reference to FIG. Is formed. Therefore, the hub fixing piece 9
In the upper end portion of 0, a portion corresponding to the hub guide portion 92 has a conical tapered surface.

Further, the hub fixing piece 90 has a peripheral groove 94 formed in the outer peripheral portion.

Also in this embodiment, the outer diameter of the rotary shaft 20 is Φ
E, when the outer diameter of the hub fixing piece 90 is ΦD, there is a relationship of the following formula ΦD−ΦE = 0.4 mm to 1.5 mm. The hardness of the hub fixing piece 90 is equal to or lower than the hardness of the rotating shaft 20.

The disk drive 10 constructed as described above
In manufacturing this embodiment, the hub fixing piece 90 and the turntable 30 are integrated by outsert molding the hub fixing piece 90 when the turntable 30 made of synthetic resin is molded with a resin. Therefore, by forming the circumferential groove 94 in the outer peripheral portion of the hub fixing piece 90, the fixing strength between the turntable 30 and the hub fixing piece 90 can be increased. When the turntable 30 and the hub fixing piece 90 are fixed, press fitting is performed, and the hardness of the hub fixing piece 90 is equal to the hardness of the rotating shaft 20.
Alternatively, since it is low, the rotating shaft 20 is not deformed.

The other configurations are the same as those of the first embodiment, and the description thereof is omitted.

[Second Embodiment] FIG. 5 is a side view of a disk drive device according to a second embodiment of the present invention, with a portion cut away. In the disk drive of the present embodiment, the turntable and the hub fixing piece, which are characteristic parts of the present invention, have the same basic configuration as that of the first embodiment. Is attached.

As shown in FIG. 5, the disk drive device 50 of the present embodiment utilizes a small DC motor with a brush, and is a disk drive device (motor device / not shown) for rotatingly driving 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 projecting 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.

The 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 at 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 device 50 constructed as described above
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.

In this embodiment, the turntable 30
The turntable 3 is fixed to the upper end of the rotating shaft 60.
On the upper surface of the disk 0, a ring-shaped attracting magnet 17 for disk clamping is formed. On the outer peripheral side of the upper surface of the turntable 30, a disc mounting portion 35 for supporting a disc is provided.
Is formed in a ring shape, and a ring-shaped rubber sheet 36 is stuck thereon. In the present embodiment, the turntable 30 is made of a metal having properties as a magnetic material,
In the turntable 30, the bottom wall 31 below the attraction magnet 17 functions as a back yoke.

In this embodiment, the turntable 30 is not directly fixed to the rotating shaft 60 at the upper end of the rotating shaft 60, but is a metal hub fixing piece 90 fixed to the upper end of the rotating shaft 60. Has been fixed through. The hub fixing piece 90 has a cylindrical portion 9 into which the upper end portion of the rotating shaft 60 fits.
1 and the hub 2 of the disk 200 described with reference to FIG.
A hub guide portion 92 that fits into the central hole 202 of the first guide 01 and guides the hub 201 is formed. That is, a portion corresponding to the hub guide portion 92 in the upper end portion of the hub fixing piece 90 has a conical tapered surface.

The hub fixing piece 90 fixed to the rotating shaft 60 is provided in the shaft hole 3 formed in the center of the turntable 30.
The turntable 30 is fixed to the upper end portion of the rotating shaft 60 by being fitted in the turntable 3.

Here, the outer diameter of the hub fixing piece 90 is larger than that of the rotary shaft 60. For example, when the outer diameter of the rotating shaft 60 is ΦE and the outer diameter of the hub fixing piece 90 is ΦD, there is a relationship of the following formula: ΦD−ΦE = 0.4 mm to 1.5 mm. The hardness of the hub fixing piece 90 is equal to or lower than the hardness of the rotating shaft 60.

The disk drive 50 thus constructed
Also, in the same manner as in the first embodiment, the upper end portion of the rotating shaft 60 is pressed into the cylindrical portion 91 of the hub fixing piece 90. Even if such press-fitting is performed, the hardness of the hub fixing piece 90 is equal to or lower than the hardness of the rotating shaft 60,
0 is not deformed.

On the other hand, the hub fixing piece 90 and the turntable 3
0 is fixed, for example, by using the turntable 30
The hub fixing piece 90 fixed to the rotating shaft 60 is press-fitted into the shaft hole 33 of the rotary shaft 60. In fixing the turntable 30 to the hub fixing piece 90, the hub fixing piece 90 may be shrink-fitted into the shaft hole 33 and fixed.

As described above, the disk drive 5 of the present embodiment
0, the radial bearing 64 is not a large-diameter bearing such as a ball bearing, but a small-diameter bearing that forms the outer peripheral surface of the rotating shaft 60 and the sliding surface 66. By using the disk drive, the size and thickness of the disk drive device 50 are reduced. Further, the rotating shaft 60 and the turntable 30 are fixed via the hub fixing piece 90 separate from the rotating shaft 60, and
Since the hub fixing piece 90 is used for guiding the hub of the disk (see FIG. 6), even if the diameter of the rotating shaft 60 is reduced, the hub fixing piece 90 has a central hole 202 formed in the hub 201 of the disk 200. The same effects as in the first embodiment can be obtained, for example, the outer diameter can be formed so as to be able to be guided.

In this embodiment, in order to rotate the disk horizontally, it is required that the rotating shaft 60 is 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. Thus, the mounting plate 8
If the bearing holding hole 81 is formed at a right angle with 0 as a reference plane,
Since the radial bearing 62 can be fixed at a right angle to the mounting plate 80, the right angle between the mounting plate 80 and the rotating shaft 60 can be easily obtained.

[0072]

As described above, in the disk drive device according to the present invention, the radial bearing is not a bearing having a large outer diameter such as a ball bearing, but is formed by the outer peripheral surface of the rotating shaft and the sliding surface. Using small diameter bearings
In addition, by using a rotating shaft having a small diameter, the size and thickness of the disk drive device can be reduced. Further, since the rotating shaft and the turntable are fixed to each other through a hub fixing piece separate from the rotating shaft, and the hub fixing piece is used for guiding the hub of the disk, even if the diameter of the rotating shaft is reduced, the hub can be used. The fixing piece can be formed to have an outer diameter dimension that can guide the center hole formed in the hub of the disk. Further, even if the diameter of the rotating shaft is reduced, the turntable is fixed with a sufficient fixing span to the hub fixing piece having the same thickness as the conventional one, so that the runout is the same as that of the conventional product.
Furthermore, since the hub fixing piece has a hardness equal to or less than that of the rotating shaft, the rotating shaft is not distorted by the stress when the rotating shaft is fitted inside the hub fixing piece. Furthermore, since the rotating shaft and the hub fixing piece having different outer diameters are made as separate parts, they are manufactured as parts having the same outer diameter in the length direction, so that the rotating shaft and the hub fixing piece are each higher. Can be manufactured with dimensional accuracy.

[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 graph showing the relationship between the structure of the disk drive device and the degree of surface runout.

FIG. 3 is a half sectional view of a disk drive device according to a first modification of the first embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a disk drive device according to a second modification of the first embodiment of the present invention.

FIG. 5 is a side view of the disk drive device according to Embodiment 2 of the present invention, with a portion cut away.

FIG. 6 is a cross-sectional view of a conventional disk drive.

7 is an explanatory diagram of a countermeasure product for solving the problem of the disk drive device shown in FIG. 6;

[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 Adsorption magnet 18 Thrust bearing 20, 60 Rotating shaft 21 Upper end portion of rotating shaft 29, 66 Sliding surface 30 Turntable 33 Shaft hole 35 Disk Mounting part 36 Rubber sheet 40 Commutator 45 Brush 59 Shaft lead-out 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 90 Hub fixing piece 91 Cylindrical Part 92 hub guide part 94 peripheral groove formed in hub fixing piece

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D038 BA04 CA05 5D109 BB02 BB12 BB17 BB21 BB22 BB31 5H019 AA06 AA07 AA08 CC04 DD01 EE01 EE14 FF01 FF03 GG01

Claims (6)

[Claims] 1. A rotating shaft, a radial bearing that forms a sliding portion with an outer peripheral surface of the rotating shaft and rotatably supports the rotating shaft, and a disk mounting turntable fixed to the rotating shaft. A disk drive device having a hub guide portion that guides the hub by entering a central hole formed in a hub of the disk at a tip end side of the rotation shaft, wherein the rotation shaft and the turntable are provided. Is fixed via a hub fixing piece on which the rotary shaft is fitted inside and the hub guide portion is formed. The hub fixing piece has an outer diameter larger than an outer diameter of the rotary shaft. A disk drive device having dimensions and hardness equal to or lower than the hardness of the rotating shaft. 2. The disk drive according to claim 1, further comprising a rotor yoke fixed to the turntable, wherein the rotor yoke is formed with a driving magnet facing the stator core. 3. The disk drive according to claim 1, wherein the difference between the outer diameters of the hub fixing piece and the rotary shaft is in a range from 0.4 mm to 1.5 mm. 4. The method according to claim 1, wherein
The disk drive device, wherein the turntable is made of metal having a shaft hole in the center, and the hub fixing piece is press-fitted and fixed in the shaft hole. 5. The method according to claim 1, wherein
The turntable is made of metal having a shaft hole in the center, and the hub fixing piece is shrink-fitted and fixed in the shaft hole. 6. The method according to claim 1, wherein
The disk drive device, wherein the turntable is a resin molded product, and the hub fixing piece having a groove formed on an outer peripheral side surface is fixed at the center of the turntable by outsert molding.