JP2575397Y2 - Chucking device for magneto-optical disk / spindle motor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk chucking device for a magneto-optical disk spindle motor.

[0002]

2. Description of the Related Art In recent years, with the spread of personal computers, large-capacity and small external storage devices have become indispensable. The magneto-optical disk drive has a large capacity,
It is expected as an external storage device capable of low bit cost, random access, and disk exchange, and is being rapidly developed with a view to personal use and aiming at further miniaturization. Accordingly, there is a demand for a smaller and thinner disk drive spindle motor. The magneto-optical disk spindle motor includes a driving unit for generating a disk driving force, and a chucking mechanism for transmitting the driving force to the disk.

As a chucking method for a magneto-optical disk, a magnet clamp method utilizing magnetic attraction is defined as a standard standard of a 3.5-inch size magneto-optical disk device. Since the device repeatedly starts and stops and attaches and detaches the disk frequently, the magnetic attraction force must be controlled within a range where the disk does not slip and the disk does not exceed the allowable amount of stress when it is attached or detached. It is extremely important for security.

A chucking mechanism and a motor structure of a conventional magneto-optical disk / spindle motor will be described below.

FIG. 4A shows a chucking mechanism of a conventional magneto-optical disk spindle motor, and FIG.
FIG. 4A is a sectional view taken along the line XX ′ of FIG. FIG.
1 shows the structure of a conventional magneto-optical disk / spindle motor.

In each of the drawings, the same components are denoted by the same reference numerals, and the magneto-optical disk is indicated by D in each of the drawings.

In FIG. 4 (a), reference numeral 1 denotes a shaft which engages while positioning the center of rotation of the magneto-optical disk D, and which rotates integrally with the magneto-optical disk D at a predetermined number of rotations; The magneto-optical disk D is placed on the portion A to position the magnetic disk D in the height direction, and the spindle hub 2b fixed to the shaft 1 by press-fitting or bonding is formed of a soft magnetic material at the center of the magneto-optical disk D. The suction plate M is removed from the gap G1.
The chucking magnet 2c is magnetized to a plurality of poles to fix the magneto-optical disk D to the upper end A of the spindle hub 2a, and the magnetic chuck 2c is made of a soft magnetic material.
A chucking yoke forming a magnetic path of the chucking magnet 2b. The chucking magnet 2b is fixed to the chucking yoke 2c, and the chucking yoke 2c is fixed to the spindle hub 2a by bonding or press fitting.
The above-described shaft 1, spindle hub 2a, chucking magnet 2b, and chucking yoke 2c constitute a chucking mechanism.

In FIG. 5, 3a is a field magnet, 3b
Is a magnetic path yoke for forming a magnetic path of the field magnet 3a. The rotor composed of the field magnet 3a and the magnetic path yoke 3b is fixed to the spindle hub 2 by caulking or bonding.
a. 4a and 4b are drive coils, 4c is a stator core, and drive coils 4a and 4b
And a stator core 4c constitutes a stator.

Reference numeral 5 denotes a circuit board on which an element such as an IC for driving a motor or a printed pattern is mounted, and 6 denotes a chassis (not shown) of the apparatus main body and the circuit board 5, which are bonded or press-fitted to the stator. 6a is an engaging portion for engaging the housing 6 with the chassis, 6b is an engaging portion for engaging the circuit board 5, 6c is an engaging portion for engaging the stator core 4c, and 7a and 7b are A bearing engages the inner diameter side with the shaft 1 and the outer diameter side engages with the housing 6, and 8 denotes a screw fixing the shaft 1 and the bearings 7a and 7b.

A magneto-optical disk constructed as described above
The operation of the chucking mechanism of the spindle motor will be described below. First, in the magneto-optical disk D inserted in the magneto-optical disk device, the center of the suction plate M formed of a soft magnetic material at the center thereof is drawn substantially to the center of the shaft 1 of the spindle motor. Next, the suction plate M
Are the chucking magnet 2b of the spindle motor, the chucking yoke 2c, and the gap G1.
Is fixed to the upper end portion A of the spindle hub by a magnetic attraction force (chucking force) determined by a magnetic circuit constituted by:

[0011]

However, in the above-mentioned conventional structure, the magnetic attraction force is the gap G1 between the attraction plate M and the chucking magnet 2b, the chucking magnet 2
The size of b changes greatly depending on factors such as the variation of the magnetization and the magnetization. It required enormous costs such as management.

Further, as the gap G1 between the attraction plate M and the chucking magnet 2b becomes smaller, and as the thickness of the chucking magnet 2b becomes thinner, the change in magnetic attraction force becomes larger. Had.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a means for realizing a high-precision, low-cost chucking mechanism of a magneto-optical disk spindle motor.

[0014]

In order to achieve this object, the chucking mechanism of the magneto-optical disk spindle motor according to the present invention is provided at least in a plane of a chucking yoke 2c on which the chucking magnet 2b is mounted. One opening is provided so that the chucking magnet 2b rotates in the circumferential direction on the plane of the chucking yoke 2c.

[0015]

According to this construction, at least one portion is newly provided on the plane of the chucking yoke 2c in the conventional magnetic circuit constituted by the suction plate M, the chucking magnet 2b of the spindle motor, the chucking yoke 2c, and the gap G1. By providing the opening 2d, the magnetic circuit is changed according to the relative position between the opening 2d of the chucking yoke 2c and the magnetic flux density distribution position of the magnetic circuit of the chucking magnet 2b to change the state of the magnetic flux density distribution. The suction plate M and the chucking magnet 2b
The magnetic circuit can be adjusted according to the gap G1, the size of the chucking magnet 2b, and the variation factors such as the variation in the magnetization, so that the variation in the chucking force can be absorbed.

[0016]

(Embodiment 1) A first embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a shaft which engages while positioning the center of rotation of the magneto-optical disk D, and rotates at a predetermined rotation speed integrally with the magneto-optical disk D;
a is a spindle hub fixed on the shaft 1 by press-fitting or bonding, and 2b is a soft magnetic material placed at the center of the magneto-optical disk D. The chucking magnet 2 is magnetically attracted to four poles to magnetically attract the attraction plate M formed through the gap G1 and fixes the magneto-optical disk D to the upper end A of the spindle hub 2a. The chucking yoke 2c is configured to form a magnetic path of the chucking magnet 2b.
a is fixed to each of them by bonding or press fitting.

Reference numeral 2d denotes two openings provided in the plane of the chucking yoke 2c, and 2e denotes a switching portion between the magnetic poles N and S of the chucking magnet 2b magnetized to four poles. It is in a magnetized state. The above shaft 1, spindle hub 2a, chucking magnet 2
b, chucking yoke 2c, chucking yoke 2c
The opening 2d forms a chucking mechanism.

Reference numeral 3a denotes a field magnet, and 3b denotes a magnetic path yoke for forming a magnetic path of the field magnet 3a. The rotor composed of the field magnet 3a and the magnetic path yoke 3b is fixed to the spindle hub 2a by caulking or bonding.

The magneto-optical disk constructed as described above
Fig. 1 shows the chucking mechanism of the spindle motor.
The operation will be described with reference to FIGS. 3 (b) and 3 (c) and FIGS. 3 (a) and 3 (b).

First, as shown in FIG. 1B, the opening 2d of the chucking yoke 2c and the chucking magnet 2
When the chucking magnet 2b is placed on the chucking yoke 2c so that the N-pole and S-pole switching portions 2e of the magnetic circuit b coincide with each other, the N-pole and S-pole switching portions 2
Since e is in a non-magnetized state, the chucking magnet 2
a chucking yoke 2c below the non-magnetized portion 2e
The opening 2d has almost no effect on the surface magnetic flux density distribution state of the chucking magnet 2b as shown in FIG. 3 (a). The chucking force of 2b does not change.

On the other hand, the relative positional relationship between the chucking magnet 2b and the chucking yoke 2c in the circumferential direction is changed, and the switching portion 2e of the magnetic pole N and S poles of the chucking magnet 2b is changed to the opening 2d of the chucking yoke 2c.
If the opening 2d of the chucking yoke 2c is located between the switching portions 2e of the magnetic poles N and S, the opening 2d of the chucking yoke 2c blocks the magnetic circuit of the chucking magnet 2b. Thus, as shown in FIG. 3B, the state of the surface magnetic flux density distribution of the chucking magnet 2b is affected, and the chucking force for attracting the suction plate M can be reduced.

As described above, according to the present embodiment, the suction plate M
In the conventional magnetic circuit constituted by the chucking magnet 2b of the spindle motor, the chucking yoke 2c, and the gap G1, at least one opening 2d is newly provided in the plane of the chucking yoke 2c. The gap G1 between the suction plate M and the chucking magnet 2b is adjusted by circumferentially adjusting the relative position between the opening 2d of the chuck 2c and the magnetic flux density distribution position of the magnetic field magnetized in the chucking magnet 2b. Since the magnetic circuit can be adjusted according to the size of the king magnet 2b and the variation factors such as the variation in the magnetization, the variation in the chucking force can be absorbed.

(Embodiment 2) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

In FIG. 2, reference numeral 1 denotes a shaft which engages while positioning the center of rotation of the magneto-optical disk D and rotates at a predetermined rotation speed integrally with the magneto-optical disk D;
The reference numeral a designates a spindle hub fixed on the magnetic path yoke 3b made of a soft magnetic material by press-fitting or bonding, with the magneto-optical disk D placed on the upper end A for positioning in the height direction.
b is magnetized to four poles in order to magnetically attract an attraction plate M formed of a soft magnetic material at the center of the magneto-optical disk D via a gap G1, and the magneto-optical disk D is attached to the upper end A of the spindle hub 2a. The magnetic path yoke 3b forms the magnetic path of the chucking magnet 2b and the magnetic path of the field magnet 3a, and the chucking magnet 2b is fixed to the top surface of the magnetic path yoke 3b by bonding or the like. ing.

Reference numeral 2d denotes two openings provided in the plane of the magnetic path yoke 3b, and 2e denotes a switching portion between the magnetic poles N and S of the chucking magnet 2b magnetized into four poles. It is in a magnetized state. The above-described shaft 1, spindle hub 2a, chucking magnet 2b, magnetic path yoke 3b, and opening 2d of the magnetic path yoke 3b constitute a chucking mechanism.

In the first embodiment, the chucking yoke 2c and the magnetic path yoke 3b in FIG. 1A are separately provided. In this embodiment, the chucking yoke 2c and the magnetic path yoke 3b are integrally formed of a soft magnetic material. The second embodiment is different from the first embodiment in that an opening 2d is formed in the first embodiment.

In the second embodiment, the spindle hub 2a and the chucking yoke 2c are separately formed, and the chucking yoke 2c and the magnetic path yoke 3b are integrally formed of a soft magnetic material. Although the opening 2d is provided on the top surface, the chucking yoke 2c and the magnetic path yoke 3b are separated, and the spindle hub 2a and the chucking yoke 2c are integrally formed of a soft magnetic material. The same effect as the present invention is exerted.

[0029]

As described above, according to the present invention, at least one opening is provided in a chucking yoke made of a soft magnetic material on which a chucking magnet is mounted, in a chucking mechanism of a magneto-optical disk spindle motor. The switching between the magnetic poles N and S of the chucking magnet is formed so as to change the relative positional relationship between the chucking magnet and the chucking yoke in the circumferential direction, so that the distance between the suction plate and the chucking magnet is changed. Even if variations such as variations in the dimensions and magnetization of the chucking magnet occur, the relative positional relationship between the chucking magnet and the chucking yoke in the circumferential direction is changed, and the magnetic flux of the chucking magnet passing through the chucking yoke. The amount can be reduced and adjusted, and as a result, the variation in chucking force is absorbed. An excellent chucking device for a magneto-optical disk / spindle motor that can be thinned with high accuracy and low cost without employing high-precision parts, minimizing the magnetizing management cost of the chucking magnet, and minimizing the cost. Can be realized.

[Brief description of the drawings]

1A is a sectional view of a chucking mechanism of a magneto-optical disk spindle motor according to a first embodiment of the present invention; FIG. 1B is a cross-sectional view of the magneto-optical disk spindle motor according to the first embodiment; FIG. 1A is a cross-sectional view for explaining the operation of the mechanism section, and FIG. 1C is a sectional view for explaining the operation of the chucking mechanism section of the magneto-optical disk spindle motor in the first embodiment. XX 'sectional view in a)

2A is a sectional view of a chucking mechanism of a magneto-optical disk spindle motor according to a second embodiment of the present invention; FIG. 2B is a cross-sectional view of the magneto-optical disk spindle motor according to the second embodiment; FIG. 1C is a sectional view taken along the line XX 'in FIG. 1A for explaining the operation of the mechanism. FIG. 1C is a view for explaining the operation of the chucking mechanism of the magneto-optical disk spindle motor in the second embodiment. XX 'sectional view in a)

FIG. 3 (a) is a chucking magnet surface magnetic flux distribution diagram for explaining the operation of the chucking mechanism of the magneto-optical disk spindle motor in the embodiment; FIG. 3 (b) is a chuck of the magneto-optical disk spindle motor in the embodiment; Chucking magnet surface magnetic flux distribution diagram for explaining the operation of the king mechanism

4A is a cross-sectional view of a chucking mechanism of a conventional magneto-optical disk spindle motor. FIG. 4B is a cross-sectional view of the chucking mechanism of the conventional magneto-optical disk spindle motor taken along the line XX '. Figure

FIG. 5 is a sectional view of a conventional magneto-optical disk spindle motor.

[Explanation of symbols]

Reference Signs List 1 shaft 2a spindle hub 2b chucking magnet 2c chucking yoke 2d opening 2e magnetic pole N pole magnetized by chucking magnet
Switching part of S pole 3a Field magnet 3b Magnetic path yoke 4a, 4b Drive coil 4c Stator core 5 Circuit board 6 Housing 6a Engagement part with device chassis 6b Engagement part with circuit board 6c Engagement part with stator core 7a , 7b bearing 8 screw A upper end of spindle hub D magneto-optical disk G1 air gap M suction plate

Claims (2)

(57) [Scope of request for utility model registration] 1. A rotor comprising a field magnet and a magnetic path yoke, a shaft fixed to the center of the rotor and rotatably supported, and a spindle hub fixed to the shaft and mounting a disk on an upper end thereof. Magnetically attracts an attraction plate made of a soft magnetic material to the center of the magneto-optical disk,
A plurality of chucking magnets fixed to the disk at the upper end of the spindle hub, and a chucking yoke formed of a soft magnetic material and forming a magnetic path of the chucking magnet. In the chucking device for a magnetic disk / spindle motor, at least one opening is provided in the chucking yoke on which the chucking magnet is mounted, and a magnetic flux density of a magnetic field magnetized to a plurality of poles in the chucking magnet. The chucking device for a magneto-optical disk / spindle motor, wherein the opening is formed so that the relative position between the distribution position and the opening of the chucking yoke can be adjusted. 2. The chucking device for a magneto-optical disk spindle motor according to claim 1, wherein said chucking yoke and said magnetic path yoke are integrally formed.