JPH03100966A - Disk driving device - Google Patents

Abstract

PURPOSE:To improve the balance of adsorbing force for a driving magnet and to make a disk driving device compact by providing a recessed part in the stator yoke of the moving part of a magnetic head in the disk driving device using a surface facing type spindle motor. CONSTITUTION:A bearing 3 is a large diameter radial bearing and a spindle 5 is fixed on the inside of the inner wheel. A rotor 6 is fixed to the spindle 5. Accordingly, the attracting force of a driving magnet 5, the rotor 6 receives force upward and prepressure is loaded to the bearing 3 by the attracting force. Then, the bearing 3 is made stable. The part of a magnetic head 11 to be inserted is narrowed down and a recessed part 10a of a stator yoke 10 is formed. A yoke 31 is provided on the inside of one or plural driving coils 9 in the parts which are faced each other through the recessed part 10a and a bearing 3. Then, the attraction balance of the driving magnet 7 is maintained. For this yoke 31, the stator yoke 10 can be narrowed down in the recessed part and the second recessed part can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a disk drive device for rotationally driving a disk-shaped recording medium such as a floppy disk.

[Prior art] Figure 4 shows a conventional floppy disk drive (hereinafter referred to as FD).
1 is a side sectional view schematically showing the configuration of the main parts of the main body (referred to as D), in which 1 is a chassis made of aluminum die-casting or pressing as the base of the main body, 2 is a medium on which information is recorded and reproduced (
23 and 23' are bearings that pivotally support the spindle 25 that drives and holds the medium. Media 2 is secured by a clamp mechanism (not shown).

It is fixed to the spindle 25. A rotor 26 has a drive magnet 7 fixedly held inside thereof.

8 is a printed circuit board (PCB) for the disk drive motor.
), 29 is an air-core drive coil arranged in a plane at predetermined intervals, and applies rotational force to the drive magnet 7 using electromagnetic conversion force by a well-known current switching method.

A stator yoke 10 forms a closed magnetic path with the drive magnet 7. A magnetic head 11 records and reproduces information on the medium 2, and is fixed to a head carriage (not shown) and is movable in the direction of the arrow in the figure.

22 is a set screw that fixes the rotor 26 and spindle 25, and 13 is a housing that holds and fixes the bearings 23 and 23', which is fixed to the chassis l.

[Problems to be Solved by the Invention] However, the above conventional example has the following problems.

■There is a limit to how thin the bearing part can be made, since it overlaps the spindle, bearing, and rotor.

(2) The thickness of the magnetic head is added to the thickness of the motor, and there is a limit to how much the sum of the thickness of the magnetic head and the motor can be reduced by any method.

This invention was made in order to solve such conventional problems, and in addition to improving the balance of the attraction force of the drive magnet, the thickness of the magnetic head and motor is absorbed by other parts, thereby reducing the overall thickness of the device. An object of the present invention is to provide a disk drive device that can be configured into a U-shape.

[Means for Solving the Problems] In order to achieve the above object, the disk drive device of the present invention eliminates the coil in the part corresponding to the moving part of the magnetic head, and makes the stator yoke in that part concave. A first recess is formed in the stator yoke, and a magnetic head is movably disposed in the first recess of the stator yoke.

Another yoke is provided inside at least one drive coil in a portion facing the first recess of the stator yoke via a bearing, or a second recess is formed in the stator yoke, and the second recess of the stator yoke is The structure is such that the suction balance of the recesses 1 to 1 can be balanced.

[Function] According to the above configuration, by providing an adsorption balance with the concave portion of the stator yoke, inclination of the drive magnet and spindle is eliminated and the overall thickness of the device is reduced. Incidentally, cogging can be reduced by devising each shape.

[Embodiment] Fig. 1 is a side sectional view showing an embodiment of the 5'' floppy disk drive device of the present invention, Fig. 2 is a diagram showing the magnetized state of the drive magnet, and Fig. 3 is a diagram showing the arrangement of the drive coil. It is a diagram.

In Fig. 1, the same reference numerals as in Fig. 4 indicate the same or equivalent parts, so the explanation will be omitted. 5 is fixed. Reference numeral 4 denotes a retaining ring, which is fixed to the chassis l with a clamper (not shown). The rotor 6 is fixed to the spindle 5 with a set screw 12. Therefore, due to the attraction force of the drive magnet 7.

The rotor 6 receives an upward force, and its suction force applies preload to the bearing 3 to stabilize it. Further, 9 is an air-core drive coil, 10 is a stator yoke, and this stator yoke l
0 is fixed to the chassis 1 by fixing or screwing.

The portion into which the magnetic head 11 is inserted is constricted to form a recess 10a of the stator yoke 10. This recess 10a
There is no space for the part, but if the drive magnet is magnetized with 14 poles (4x3+2) as shown in Figure 2, the third
As shown in the figure, there are nine drive coils, and the portions corresponding to the two poles can be made into spaces, and the recesses 10a of the stator yoke 10 can be brought into the spaces. As a result, it can be driven according to the well-known three-phase full-wave drive method.

Further, 31 is a yoke, and the recess 10 of the stator yoke lO
It is provided at one of the portions facing a and the bearing 3 via the bearing 3, or inside the plurality of drive coils 9, and balances the attraction of the drive magnet 7. When the attraction balance is disrupted, the rotor tilts toward the side with greater attraction force, resulting in poor parallelism and runout of the spindle, making the contact between the media and the magnetic head unstable, and causing errors when reading and writing data. The adsorption balance of the rotor is measured at both ends facing each other via a bearing, and if the respective values differ by 20% or more, the above problem will occur. Similar to the recess 10a, this yoke 31 may form a second recess by squeezing the stator yoke lO into a recess.

The concave portion 10a of the stator and the yoke 31 or the second concave portion of the stator also have the effect of increasing the upward suction force of the rotor, and the preload of the bearing 3 is stabilized when the rotor suction car media clamp force is >300g, so the above-mentioned The recess 10a and the yoke 31 or the second
By providing a concave portion, rotational stability of the bearing is also ensured.

[Effects of the Invention] As explained above, the present invention provides a disk drive device using a surface facing type spindle motor, by forming a first recess in the stator yoke of the moving part of the magnetic head. The thickness can be reduced, and the entire device can be made thinner.

In addition, by using a three-phase system and setting the number of magnetized coils to 4n+2 for the number of drive coils of 3n, a gap can be created in the portion corresponding to two poles, and the stator yoke can be fitted into the recessed part. , it becomes possible to reduce the thickness. Furthermore, the suction balance can be maintained by providing another yoke inside the air-core drive coil that faces the recess of the stator yoke via a bearing, or by forming a second recess in the stator yoke.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing an embodiment of the disk drive device of the present invention, FIG. 2 is a diagram showing the magnetized state of the drive magnet,
FIG. 3 is a layout diagram of a drive coil, and FIG. 4 is a side sectional view showing a schematic configuration of the main parts of a conventional floppy disk drive device. In the figure. l: Chassis 2: Media 3: Bearing 4: Retaining ring 5 Varnish bottle 6: Rotor
7: Drive magnet 8: PCB 8
a: opening

Claims (1)

[Claims] In a disk drive device equipped with a surface-facing spindle motor, the coil in the part corresponding to the part where the magnetic head moves is removed, and the stator yoke in that part is made concave to form a first concave part. A disk drive device in which a magnetic head is movably disposed in a first recess of a yoke, wherein another yoke is provided inside at least one drive coil in a portion facing the first recess of the stator yoke via a bearing. A disk drive device characterized in that the stator yoke is provided with a second recess or a second recess is formed in the stator yoke so that the suction balance of the first recess of the stator yoke can be maintained.