JP2003070206A - Spindle motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spindle motor which can avoid the centrifugal whirling of a shaft with a simple structure. SOLUTION: This spindle motor 10 has a fixed bearing 12, a rotor 20 which is rotatably supported by a rotary shaft 24 attached in the bearing and on which a disc-type medium is placed, a stator 11 provided around the bearing, and a turntable 30 which is attached to one end of the rotary shaft and holds the disc-type medium. The outer circumferential edge of the rotor has a flange 21a extended radially, and the flange is attracted by magnet members 40 and 45 provided on a base 16 supporting the bearing so as to have the rotary shaft eccentric.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor for rotating a disk-shaped medium, for example.

[0002]

2. Description of the Related Art Conventionally, such a spindle motor is
For example, it is configured as shown in FIG. That is, in FIG. 4, the spindle motor 1 includes a stator 2 and a bearing 3
The rotor 4 is rotatably supported by the rotor 4, and the turntable 5 is attached to the upper end of the rotation shaft of the rotor 4.

The stator 2 is a core 2 arranged in an annular shape.
a and a coil 2b wound around the core 2a.

The bearing 3 is a sintered bearing impregnated with lubricating oil, and is perpendicular to the stator 2 via the bearing housing 3a at the center position of the annular shape of the core 2a of the stator 2. It is fixed. The bearing housing 3a
Is attached to an iron base 2c, and a stator substrate 2d made of a printed circuit board is attached to the iron base 2c.

On the other hand, the rotor 4 has a hollow cylindrical rotor yoke 4a with one end open, and a rotor yoke 4a.
Rotor magnet 4b mounted along the inner peripheral surface of the
A bush 4c fixedly held at the center of the rotor yoke 4a, a rotating shaft 4d attached to the bush 4c,
It consists of

When the rotary shaft 4d is mounted on the bearing 3, the lower end in the drawing is attached to the lower end of the bearing housing 3a by caulking or the like so as not to move along the axial direction. It comes into contact with the board 3b via a thrust washer 3c made of nylon, for example.

The turntable 5 has a known structure, and is, for example, CD, CD-ROM, CD-R, RW.
A center hole of an information recording disk such as the above or a storage device such as the FDD is fixedly held by engaging with the central turntable portion 5a.

[0008] The spindle motor 1 configured as described above
According to this, by passing a current through the coil 2b of the stator 2, the magnetic field generated in the coil 2b interacts with the magnetic field of the rotor magnet 4b via the rotor yoke 4a of the rotor 4, and the rotor 4 is rotationally driven. Will be done.

[0009]

However, in the spindle motor 1 having such a structure, when the rotary shaft 4d is mounted on the sintered bearing 3, the rotary shaft 4d is mounted on the basis of the clearance α shown in FIG. However, this clearance α becomes loose, and there is a case in which a shaft runout occurs during rotation at an angle of θ ° shown in FIGS. 8 (A) and 8 (B) during rotation. CD-ROM, CD-
There has been a problem that a read / write error or the like occurs when reading or writing data in an information recording disk such as R or RW or a storage device such as FDD.

In view of the above points, it is an object of the present invention to provide a spindle motor which has a simple structure and prevents shaft runout during rotation.

[0011]

According to the invention, the above object is achieved according to the invention by means of a fixedly arranged bearing (12) and this bearing (1).
2) A rotor (20) rotatably supported by a rotating shaft (24) mounted in the rotor (20) on which a disk-shaped medium is placed, and a stator (11) provided around a bearing (12). And a turntable (30) attached to one end of the rotating shaft (24) for holding a disk-shaped medium, the spindle motor (10).
The outer peripheral edge of the rotor (20) is provided with a flange portion (21a) extending radially outward, and the flange portion (21a) is provided on the base (16) supporting the bearing (12). This is achieved by a spindle motor (10), which is attracted so that the rotation shaft (24) is eccentric with respect to the magnet member (40).

Spindle motor (10) according to the present invention
Preferably, the magnet member (40) is magnetized with N and S poles on the front and back surfaces of the end face.

Spindle motor (10) according to the present invention
Preferably, the magnet member (40) is magnetized so that N poles and S poles are alternately arranged along the circumferential direction.

Spindle motor (10) according to the present invention
Preferably, the magnet member (40) is provided over an approximately one-quarter region of the flange portion (21a) of the rotor (20).

According to the above construction, the outer peripheral edge of the rotor (20) is provided with the flange portion (21a) extending radially outward, and the flange portion (21a) is provided with the bearing (1).
Permanent magnets provided on the base (16) supporting 2), the N and S poles are magnetized on the front and back surfaces of the end faces, or the N and S poles are alternately arranged along the circumferential direction. Since the rotating shaft (24) is attracted to the magnetized magnet member (40) so as to be eccentric, shaft runout during rotation can be prevented.

When the magnet member (40) is provided over an approximately one-quarter area of the flange portion (21a) of the rotor (20), the flange portion of the rotor (20). Since (21a) is sucked over a wide range, it is possible to more reliably prevent shaft runout during rotation. It should be noted that the reference numerals in the above parentheses are given for easy understanding and are merely examples, and the present invention is not limited to these.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on the embodiments shown in the drawings. FIG. 1 shows the configuration of a first embodiment of a spindle motor according to the present invention. In FIG. 1, a spindle motor 10 includes a stator 11 and a rotor 2 rotatably supported by bearings 12.
0 and a turntable 30 attached to the upper end of the rotary shaft of the rotor 20.

The stator 11 includes a core 13 made of, for example, a silicon steel plate and arranged in an annular shape, and a coil 14 wound around the core 13.

The bearing 12 is, for example, a sintered bearing impregnated with lubricating oil, and the bearing housing 1 made of, for example, brass is formed at the center of the annular shape of the core 13 of the stator 11.
It is fixed perpendicularly to the stator 11 via 5. The bearing housing 15 is made of an iron base 16.
The stator base 17 is mounted on the iron base 16.

On the other hand, the rotor 20 includes, for example, a rotor yoke 21 made of an iron plate, a rotor magnet 22 mounted along the inner peripheral surface of the rotor yoke 21, and a bush 23 integrally formed at the center of the rotor yoke 21.
And a rotating shaft 24 made of, for example, stainless steel attached to the bush 23.

The rotor yoke 21 is formed in a flat hollow cylindrical shape with one end open, and a rotor magnet 22 is fixed by adhesion or the like in the circumferential direction along the inner peripheral surface of the cylindrical shape. The rotor magnet 22 is composed of a permanent magnet or is appropriately magnetized in the circumferential direction.

The rotary shaft 24 is fixedly held by being inserted into the bush 23 by press fitting or the like.

Further, the rotary shaft 24 is made of, for example, an iron plate whose lower end is attached to the lower end of the bearing housing 15 by caulking or the like so as not to move along the axial direction when mounted on the bearing 12. The thrust board 18 is brought into contact with the thrust board 18 via a thrust washer 19 made of nylon, for example.

The turntable 30 has a known structure, and is configured to hold a CD or a CD-ROM, for example, and is molded of resin, for example.

The above construction is almost the same as that of the conventional spindle motor 1 shown in FIG. 6, but the spindle motor 10 according to the present invention is different in the following points. That is, the lower end of the rotor yoke 21 forming the outer peripheral edge of the rotor 20 is provided with the flange portion 21a extending outward in the radial direction. On the other hand, on the base 16 on the stator 11 side, a raised portion 16a is provided at a position facing the flange portion 21a, and the magnet member 4 made of a permanent magnet is provided in the recessed portion of the raised portion 16a.
0 is fixed by fitting or adhesive (see also FIG. 2). In addition, this magnet member 40 is replaced with a permanent magnet,
As shown in FIG. 3, N and S poles are magnetized on the front and back surfaces of the end face, or as shown in FIG. 4, N and S poles are arranged along the circumferential direction.
The poles may be magnetized so that they are arranged alternately, which allows inexpensive formation.

Spindle motor 1 according to an embodiment of the present invention
0 is configured as described above and operates as follows. First, the disk-shaped medium is placed on the turntable 30. At this time, the center hole of the disc-shaped medium engages with the peripheral surface of the turntable 30 so that the disc-shaped medium can be positioned in the direction perpendicular to the rotation axis 24. After that, when a current is passed through the coil 14 of the stator 11, the magnetic field generated in the coil 14 interacts with the magnetic field of the rotor magnet 22 via the rotor yoke 21 of the rotor 20, so that the rotor 20 is rotationally driven. Will be. As a result, the disk-shaped medium is rotationally driven.

In this case, when the flange portion 21a formed at the lower end of the rotor yoke 21 rotates together with the rotor 20, the turntable 30 and the rotary shaft 24, the base 1
6 is magnetized with a permanent magnet, and N and S poles are magnetized on the front and back of the end face.
Alternatively, the rotating shaft 24 is attracted so as to be eccentric to the magnet member 40 that is magnetized so that the N poles and the S poles are alternately arranged along the circumferential direction, and is rotated in a state of being eccentric to one side. As a result, shaft runout during rotation can be prevented.

FIG. 5 shows an example of the magnet member 45 applied to the second embodiment of the spindle motor according to the present invention. 5, the spindle motor of the second embodiment has substantially the same configuration as the spindle motor 10 shown in FIG. 1 (not shown), and the magnet member 45 is the rotor yoke 2
It is provided along the first flange portion 21a over an approximately one-quarter region of the flange portion 21a of the rotor yoke 21.

According to the spindle motor 40 having such a structure, the same operation as the spindle motor 10 shown in FIG. 1 is performed, and the flange portion 21a formed at the lower end of the rotor yoke 21 has the rotor 20, the turntable 30, and the When rotating integrally with the rotating shaft 24, the rotor yoke 21
Along the flange portion 21a of the magnet member 45 over the approximately one-quarter area of the flange portion 21a of the rotor yoke 21.
Is provided, so that the rotary shaft 24 is eccentric,
Since it is more surely sucked and rotates in a state of being eccentric to one side, shaft runout during rotation can be reliably prevented.

In the above embodiment, the bearing 12 is constructed as an impregnated sintered bearing, but it is obvious that it may be another type of bearing. Further, in the above-described embodiment, the spindle motor 10 for rotationally driving the CD or the CD-ROM has been described, but the present invention is not limited to this. It is obvious that the present invention can be applied to a spindle motor.

[0031]

As described above, according to the present invention, the outer peripheral edge of the rotor is provided with the flange portion extending outward in the radial direction, and the flange portion is provided on the base supporting the bearing. , A permanent magnet, a magnet member having north and south poles magnetized on the front and back surfaces of the end face, or magnetized so that the north and south poles are alternately arranged along the circumferential direction, and further on the outer peripheral edge of the rotor yoke. Since the stone member provided over the approximately one-quarter region is sucked so that the rotation axis is eccentric, shaft runout during rotation can be prevented.

Thus, according to the present invention, it is possible to provide an extremely excellent spindle motor which has a simple structure and which prevents shaft runout during rotation.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration of a first embodiment of a spindle motor according to the present invention.

FIG. 2 is an explanatory diagram showing a positional relationship between an outer peripheral edge of the rotor yoke of FIG. 1 and a magnet member.

3A and 3B show modifications of the magnet member shown in FIG. 1, where FIG. 3A is a plan view and FIG. 3B is a side view.

FIG. 4 shows another modification of the magnet member of FIG. 1, (A) being a plan view and (B) being a side view.

FIG. 5 is an explanatory diagram showing a positional relationship between an outer peripheral edge of a rotor yoke and a magnet member applied to a second embodiment of a spindle motor according to the present invention.

FIG. 6 is a schematic cross-sectional view showing the configuration of an example of a conventional spindle motor.

7 is an explanatory diagram showing the relationship between the rotary shaft of FIG. 6 and a sintered bearing.

8A and 8B show the rotation state of FIG. 7, and FIGS.

[Explanation of symbols]

10 Spindle motor 11 Stator 12 bearings 13 cores 14 coils 15 Bearing housing 16 base 16a ridge 17 Stator board 18 Thrust board 19 Thrust washer 20 rotor 21 rotor yoke 21a Flange part 22 rotor magnet 23 Bush 24 rotation axis 30 turntable 40,45 Magnet member

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3J011 AA02 BA02 BA10 JA02 LA01                 5D109 BA14 BA17 BA20 BB05 BB12                       BB17 BB21 BB22 BB28                 5H605 AA05 BB05 BB14 CC02 CC03                       CC04 EA02 EA07 EA18 EB05                       EB06 EB13 EB39                 5H621 AA04 GA01 HH02 HH03 JK08                       JK15 JK17 JK19

Claims (4)

[Claims] 1. A fixed bearing, a rotor rotatably supported by a rotating shaft mounted in the bearing, and a disk-shaped medium mounted on the surface of the rotor, and a stator provided around the bearing. And a turntable for holding a disk-shaped medium attached to one end of the rotary shaft, the spindle motor including a flange portion, the outer peripheral edge of the rotor extending radially outward, A spindle motor, wherein the flange portion is attracted so that the rotating shaft is eccentric with respect to a magnet member provided on a base that supports a bearing. 2. The spindle motor according to claim 1, wherein the magnet member has N and S poles magnetized on the front and back surfaces of the end surface. 3. The magnet member comprises N in a circumferential direction.
The spindle motor according to claim 1, wherein the poles and the S poles are magnetized so that they are alternately arranged. 4. The spindle motor according to claim 1, wherein the magnet member is provided over a substantially one-quarter region of the flange portion of the rotor.