JPH054132Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a disk rotation drive motor that is most suitable for application to, for example, a spindle motor of a micro floppy disk device.

[Summary of the idea]

The present invention is a disk rotation drive motor in which a rotor is attached to the motor shaft via a rotor boss, and a turntable is attached to the motor shaft above the rotor, and the turntable and rotor boss are integrally molded. By constructing a dual-purpose boss member, attaching this member to the motor shaft at the boss part, and attaching a rotor to the outer periphery of the turntable part of this member, the height of the turntable can be lowered and the motor can be made thinner. At the same time, it is possible to improve the surface runout accuracy of the turntable and rotor.

[Conventional technology]

A conventional example of a spindle motor for a microfloppy disk device will be explained with reference to FIG.

First, this motor 1 is composed of a motor shaft 2, a rotor 3, a stator 4, and a turntable 5. A pair of upper and lower bearings 9 and 10 are incorporated into a boss portion 8 provided on a chassis 7 of the disk device, and the motor shaft 2 is vertically and rotatably supported by these bearings 9 and 10 at its lower part. There is. Note that a radial rolling bearing is used for the upper bearing 9, and a radial sliding bearing made of a metal bearing is used for the lower bearing 10.

Next, a rotor boss 1 is attached to the outer periphery of the center part of the motor shaft 2.
2 is fixed by press-fitting or adhesive, and the rotor 3 is horizontally attached to this rotor boss 12. The rotor 3 is composed of a disk-shaped yoke 13 and a ring-shaped magnet 14 fixed to the lower surface of the yoke 13. A small diameter inner circumference 13a of the yoke 13 is fixed to the outer circumference of the rotor boss 12. The stator 4 is arranged horizontally below the rotor 3. The stator 4 consists of a plurality of coils 17 formed on the lower surface of a printed circuit board 16 and a yoke 18 fixed on the chassis 17. That is, the motor 1 is constituted by a flat motor in which a rotor 3 and a stator 4 face each other in plan view.

Next, the turntable 5 is horizontally attached to the upper part of the motor shaft 2. The turntable 5 is composed of a disk-shaped turntable main body 20 which is a chuck yoke and a magnetic plate 21 which is a chuck magnet fixed to the upper surface of the turntable main body 20, and the inner peripheral part of the turntable main body 20 is connected to the motor shaft 2. It is fixed to the outer periphery of the upper part by press fitting, adhesive, etc. A drive pin support lever 22 is attached to the lower surface of the turntable body 20, and a drive pin 23 is vertically fixed onto one end of this lever 22. The drive pin 23 passes through a drive pin insertion hole 24 provided in the turntable body 20 and projects upward. Note that the lever 22 is biased to move by a tension spring (not shown) so that the drive pin 23 is biased to move in a direction away from the center of the turntable 5 on the forward side in the rotational direction of the turntable 5. .

By the way, the micro floppy disk (hereinafter simply referred to as disk) 26 which is rotationally driven by the motor 1 described above has an upper and lower half 27a,
It is rotatably housed in a cartridge case 27 constituted by 27b. This disk 26
A center disk 28 made of a metal plate is fixed to the center of the center disk 28, and a center hole 29 and a drive pin insertion hole 30 are provided at the center of the center disk 28 and at positions eccentric therefrom. Note that the center hole 29 is formed in a square shape, and the drive pin insertion hole 30 is formed in a rectangular shape. Further, the center disk 28 is loosely fitted into a turntable insertion hole 31 provided in the lower half 27b.

The cartridge case 27 is inserted into a disk device having the motor 1 configured as described above. Then, the disk 26 is installed horizontally on the turntable 5 of the motor 1, and the disk 26
A center disk 28 is placed on the turntable main body 20, and a center hole 29 of the center disk 28 is placed on the turntable main body 20.
and the drive pin insertion hole 30 are inserted into the upper part of the motor shaft 2 and the drive pin 23. and center disk 28
is attracted by the magnetic plate 21 of the turntable 5, so-called magnetic chucking.

After the chuck of the disk 26 is completed, the plurality of coils 1 of the stator 4 of the motor 1 are
7, this current flows through the rotor 3.
The rotor 3 interlinks with the magnetic flux of the magnet 14.
is rotated, and the motor shaft 2 is rotated. As a result, the turntable 5 is rotated, and the disc 2 being chucked on the turntable 5 is rotated.
6 is rotationally driven. At this time, the drive pin 23
By pressing the outer peripheral side 30a of the drive pin insertion hole 30, the center disk 28 of the disk 26 is pressed.
is urged to move in the direction away from the center of the turntable 5, and the side 29 of the center hole 29 of the center disk 28
a comes into contact with the upper outer periphery of the motor shaft 2, and the center of the disk 26 is positioned at the center of the turntable 5. As the turntable 5 rotates, the drive pin 23 presses the drive pin insertion hole 30, thereby rotating the disk 26.
A magnetic head (not shown) in contact with the recording surface of the disk 26 performs desired recording and reproduction.

[Problem that the invention attempts to solve]

However, the conventional motor 1 described above has
I had the following problem.

That is, conventionally, the rotor boss 12 of the rotor 3 and the turntable body 20 of the turntable 5 are separate parts, and the rotor boss 12 and the turntable body 20 are each separately fixed to the outer periphery of the motor shaft 2. Therefore, due to the large gap S between the rotor 3 and the turntable 5, the height _H1 of the turntable 5 increases.
As a result, there was a problem that the motor 1 as a whole became thick. In particular, the motor 1 of the micro floppy disk device described above requires a space below the turntable 5 to arrange the drive pin support lever 22, so the corresponding height is also the height H ₁ of the turntable 5. This causes the temperature to rise.

Additionally, a rotor boss 12 and a turntable main body 2 are fixed to the motor shaft 2 by press fitting, adhesive, etc.
The thicknesses T ₁ and T ₂ of 0 cannot be made thicker than necessary because increasing these increases the height of the entire motor 1. For this reason, it is difficult to achieve horizontal accuracy of the rotor boss 12 and the turntable main body 20 with respect to the motor shaft 2, and the surface runout of the rotor 3 as shown by arrow a and the surface runout of the turntable 5 as shown by arrow b are likely to occur. . When surface runout occurs in the rotor 3, the rotational torque of the rotor 3 becomes unstable, and when surface runout occurs in the turntable 5, surface runout occurs in the disk 26, resulting in incomplete contact of the head with the disk 26. .

Therefore, the present invention aims to reduce the height of the turntable to make the motor thinner, and also to improve the surface runout accuracy of the turntable and rotor.

[Means for solving problems]

In the above-mentioned disk rotation drive motor, the present invention comprises integrally molding the turntable and the rotor boss to form a turntable-duty boss member, and attaching this member to the motor shaft at the boss portion. The rotor is supported on the outer periphery of the turntable portion of the member.

[Effect]

According to the present invention, in the boss member that also serves as a turntable, the boss portion and the turntable portion are integrally molded, and the rotor is attached to the outer periphery of the turntable portion, so that the rotor and the turntable portion are not connected to each other. Since there is no gap between the two, the height of the turntable can be significantly lowered.

In addition, a member in which the boss part and the turntable part are integrally molded allows the boss part attached to the motor shaft to be sufficiently thick without increasing the height of the entire motor. The horizontal accuracy of the member relative to the shaft can be easily achieved, and the surface runout accuracy of the turntable portion and rotor can be significantly increased.

〔Example〕

Hereinafter, a first embodiment will be described in which the present invention is applied to a spindle motor of a micro floppy disk device.
This will be explained with reference to the drawings and FIG. Note that the same parts as those of the conventional example described in the [Prior Art] section are given the same reference numerals, and the explanation thereof will be omitted.

First, in the motor 35 of this embodiment, a bearing 38 is incorporated in a boss portion 37 provided on the chassis 7 of the disk device, and the motor shaft 4 is attached to the bearing 38.
0 is vertically and rotatably inserted in its lower part. The length of this motor shaft 40 is shorter than the length of the motor shaft 2 of the conventional example shown in FIG. Although a radial sliding bearing made of a metal bearing is used as the bearing 38, a radial rolling bearing may also be used.

Next, a boss member 42 that also serves as a turntable is attached to the outer periphery of the motor shaft 40 from approximately the center to the top. This member 42 is integrally formed with a cylindrical boss portion 43 and a disc-shaped turntable portion 44 extending horizontally outward from the upper portion of the boss portion 43. The inner periphery of the boss portion 43 of the member 42 is fixed to the outer periphery of the motor shaft 40 from approximately the center to the upper portion by press fitting, adhesive, or the like.

Next, a rotor 46 is attached to the outer periphery of the turntable portion 44 of the member 42. The disk-shaped yoke 47 of the rotor 46 has an inner peripheral part 47a formed with a large diameter, and this inner peripheral part 47a is fixed to an annular support part 48 formed on the lower surface of the outer peripheral part of the turntable section 44. There is.

Next, by attaching the rotor 46 to the outer periphery of the turntable portion 44 of the member 42,
A space 50 is secured below the turntable portion 44. A drive pin support lever 52 having a drive pin 23 is disposed within this space 50. That is, as shown in FIG. 1, a lever 52 formed in a substantially arc shape is pivotally supported on the lower surface of the turntable portion 44 by a support shaft 53. As shown in FIG. A tension coil spring 55 is stretched between a spring locking pin 54 fixed to the lower surface of the turntable portion 44 and the other end of the lever 52, so that the drive pin 23
is urged to move away from the center of the turntable portion 44 on the front side in the rotational direction of the turntable portion 44 .

Next, a bearing 57 is interposed between the lower end surface of the boss portion 43 of the member 42 and the upper end surface of the boss portion 37 of the chassis 7. This bearing 57 consists of a plurality of steel balls 59 supported by a ring-shaped holder 58 and a pair of ring-shaped substrates 6 that sandwich these from above and below.
It is composed of thrust rolling bearings consisting of 0.0 and 61 mm. The diameter D of this bearing 57 is made sufficiently large so as not to affect the height of the motor 35. In order to prevent the motor shaft 40 from falling due to the bearing 57, the raceway surface of the substrate 60 above the bearing 57 is set to be orthogonal to the axis of the motor shaft 40. Note that as long as the bearing 57 is a thrust bearing, its structure can be modified in various ways.

According to the motor 35 configured as described above,
The boss member 42 that also serves as a turntable is the boss portion 43
and the turntable section 44 are integrally molded, and the rotor 46 is attached to the outer periphery of the turntable section 44, so that the distance between the rotor 46 and the turntable section 44 (Fig. In the conventional example, the spacing S) is eliminated, and the height _H2 of the turntable portion 44 is significantly reduced. Moreover, by attaching the rotor 46 to the outer periphery of the turntable portion 44, a space 50 is secured below the turntable portion 44, so that the drive pin support lever 52 can be placed within this space 50. Therefore, the height _H2 of the turntable portion 44 does not increase due to this lever 52.

In addition, the boss part 43 and the turntable part 44
The member 42 that is integrally formed with the motor 35 can sufficiently increase the thickness _T3 of the boss portion 43 that is fixed to the motor shaft 40 by press-fitting, gluing, etc., without increasing the overall height of the motor 35. be able to. For this reason,
The horizontal accuracy of the member 42 with respect to the motor shaft 40 can be easily achieved, and surface runout of the rotor 46 and the turntable portion 44 can be prevented.

By the way, in the motor 35 of this embodiment,
Bearing 5, which is a thrust bearing with a large diameter D
7 is configured to receive the thrust direction of the boss member 42 which also serves as a turntable. Therefore, the motor shaft 40 is prevented from falling down by the bearing 57, and the motor shaft 20 is stabilized in the left-right direction with respect to the chassis 7 by the bearing 38, so that the vibration of the motor shaft 40 is suppressed.

That is, in the structure in which radial bearings are used for the upper and lower pair of bearings 9 and 10 as explained in the conventional example in FIG.
The interval L ₁ between 10 becomes shorter. As a result, the vibration of the motor shaft 2 increases, the position of the head relative to the disk 26 becomes unstable, and tracking accuracy deteriorates. In this case, the motor shaft 2 swings about point A due to the eccentricity between the motor shaft 2 and the bearing 9 and the distance between the motor shaft 2 and the bearing 10, and the swing at the point B is the length of L ₁ and L ₂ It is determined by the ratio of Conventionally, as a countermeasure against this type of shaft vibration, it has been common practice to use rolling bearings, increase the number of press-fitted parts to the motor shaft 2 as much as possible, form a housing, and provide a preload mechanism. In addition to the problem of high cost, it is difficult.

However, in this embodiment, the large diameter D
Since the bearing 57, which is a thrust bearing, is used, the length of _L1 corresponds to the length of the diameter D. Since the value of this diameter D can be made larger than _H2 even if the height of the motor 35 is reduced, it is possible to realize a motor shaft 40 with small runout even if it is a flat motor. Using a pair of upper and lower radial bearings,
Compared to a case where a housing is formed and a preload mechanism is provided, an effective bearing can be constructed with lower parts precision and lower costs. Moreover, the bearing 57, which is a thrust bearing, can be easily assembled into the motor 35 and can be assembled automatically.

Although one embodiment of the present invention has been described above, the present invention is not limited to the embodiment, and various effective modifications can be made based on the technical idea of the present invention.

For example, in the embodiment, a turntable that performs magnetic chucking is shown, but a chucking structure in which the center core of the disk is press-fitted onto the top of the motor shaft, or a chucking structure in which the center portion of the disk is crimped onto the turntable with a clamper is also available. It can also be a structure.

Note that the present invention is not limited to the spindle motor of a microfloppy disk device, but can be applied to various types of disk rotation drive motors that rotate and drive various types of disks mounted on a turntable.

[Effect of idea]

In this invention, the turntable part and the boss part are integrally molded, and the rotor is attached to the outer periphery of the turntable part, thereby eliminating the gap between the rotor and the turntable part, which conventionally had a large gap. The height of the turntable can be significantly lowered. Therefore, the motor can be made significantly thinner, and the disk device can also be made much thinner. In particular, even in the micro floppy disk device shown in the embodiment, a space for arranging the drive pin support lever can be secured below the turntable portion, so that the turntable portion does not become high due to this lever.

Furthermore, by integrally molding the boss part and the turntable part, the thickness of the boss part attached to the motor shaft can be made sufficiently thick without increasing the height of the entire motor. It is easy to achieve horizontal accuracy with respect to the motor shaft, which was difficult in the past, and the surface runout accuracy of the turntable portion and rotor can be significantly improved. Therefore, the rotational torque of the rotor can be made extremely stable, and the head can be brought into extremely perfect contact with the disk, thereby significantly improving the recording and reproducing characteristics.

Moreover, since the boss part and the turntable part are integrated into a single piece, the number of parts and the number of man-hours required for mounting to the motor shaft are reduced, resulting in a significant cost reduction compared to the conventional two-part structure. can be achieved.

[Brief explanation of the drawing]

1 and 2 show an embodiment in which the present invention is applied to a spindle motor of a micro floppy disk device. FIG. FIG. 3 shows a conventional example of a spindle motor for a microfloppy disk device, and is a sectional view of a state in which a disk is mounted on a turntable. In addition, in the symbols used in the drawings, 4... Stator, 5... Turntable, 12... Rotor boss, 14... Magnet, 20... Turntable body, 21... Magnetic plate, 23... Drive pin, 26 ...Disk, 35...Motor, 38...
... bearing, 40 ... motor shaft, 42 ... boss member that also serves as turntable, 43 ... boss part, 44 ...
Turntable part, 46... Rotor, 47...
Yoke, 52... Drive pin support lever, 57...
It is a bearing.

Claims (1)

[Claims for Utility Model Registration] A motor shaft, a rotor attached to the motor shaft via a rotor boss to rotate the motor shaft, and a rotor attached to the motor shaft above the rotor to rotationally drive a disk. In a disk rotation drive motor equipped with an attached turntable, the turntable and the rotor boss are integrally molded to form a boss member that also serves as a turntable, and this member is attached to the motor shaft at the boss portion. Also, a motor for driving disk rotation, characterized in that the rotor is attached to the outer periphery of the turntable portion of this member.