JP2599470Y2 - Magnetic disk drive - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive, and more particularly, to a structure for preventing the rotation of a rotating shaft.

[0002]

2. Description of the Related Art As a magnetic disk drive for rotating a magnetic disk such as a floppy disk, a device using a sintered oil-impregnated bearing as a bearing is known. FIG. 4 shows a conventional example of such a magnetic disk drive.
In FIG. 4 , a hole is formed at the center of the circuit board 36, and a cylindrical bearing holder 42 is attached to the hole. A flange 42 is provided on the outer periphery of the bearing holder 42.
a is formed, and the lower surface of the flange portion 42a is
6 is in contact with the upper surface. The central through hole of the bearing holder 42 two bearings 38 and 38 are mounted vertically. A bearing of a sintered oil-impregnated type is used for the bearings 38, 38, and a central shaft 37 is used for these two bearings 38, 38.
Are inserted so as to be rotatable.

[0003] A stator core 34 is mounted on the outer peripheral surface of the bearing holder 42 below the circuit board 36.
The stator core 34 has a plurality of salient poles on the outer periphery, and the coil 33 is wound around each salient pole. Stator core 3
A spacer 35 is attached between the circuit board 4 and the circuit board 36, and a space for winding the coil 33 between the circuit board 36 and the stator core 34 is secured by the spacer 35.

A flange 37a is formed at the lower end of the central shaft 37. The cup-shaped rotor case 32 is fixed to the lower surface of the flange portion 37a by screws 43. The drive magnet 31 is attached to the inner surface of the peripheral wall of the rotor case 32. The driving magnet 31 is the stator core 3
4 with a gap. For this reason, by energizing the coil 33 wound around the salient pole, the rotor case 32 is biased, and the center shaft 37 is driven to rotate.

[0005] At the upper end of the central shaft 37, a hub base 39 for mounting a magnetic medium such as a floppy disk is fitted.

[0006]

The magnetic disk drive as described above uses a sintered oil-impregnated bearing for the bearing 38, so that a small space is created between the bearing 38 and the center shaft 37. Therefore, when the disk is placed on the hub base 39 and the central shaft 37 rotates, the central shaft 37 is wobbled or rattled as shown in FIG. 5 due to the space between the bearing 38 and the central shaft 37 . This adversely affects the magnetic disk mounted on the hub base 39. In order to eliminate the wobbling or rattling of the central shaft 37 when the central shaft 37 rotates, the central shaft 37 may be rotated by pressing the central shaft 37 in one radial direction of the bearing 38. Such a central axis 37
To obtain the rotation, as disclosed in JP-A-2-13256, fitted with a magnet to attract the rotor in one direction, there is a method of utilizing a magnetic attraction force or repulsive force of the magnet. According to this method, a sufficient effect can be obtained in terms of performance, but the cost increases because a special member such as a magnet is used. Also,
As described in Japanese Utility Model Laid-Open No. 4-2147,
There is a method in which a part of the salient poles of the stator core is cut and the balance of the respective rotating magnets is made different to press the center shaft 37 in one direction in the radial direction of the bearing 38, but a very large effect cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and provides a magnetic disk drive device which is low in cost and which prevents the wobble when the central shaft rotates. The purpose is to:

[0008]

According to the present invention, there is provided a rotor case having a cylindrical driving magnet,
A stator core in which a coil is wound around salient poles facing the inner peripheral surface of the drive magnet in the circumferential direction, a circuit board on which the stator core is mounted via a core holder, and a bearing that rotatably supports the central axis; in the circumferential opposing magnetic disk drive device comprising a hub base for one is fitted to the end by mounting the magnetic disk drive of the central axis, the core holder
To form a trapezoidal cross section and tilt the stator core in one direction.
In addition, the relationship between the salient poles of the stator core and the center of the drive magnet in the thrust direction is not parallel. The invention according to claim 2 uses a cylindrical drive magnet.
Rotor case, and the inner peripheral surface and peripheral direction of the drive magnet
Core with coils wound around salient poles facing in opposite directions
And the time when the stator core is placed via the core holder.
Circuit board, bearing that rotatably supports the central shaft, and central shaft
The magnetic disk is mounted on one end of the
And a circumferentially opposed magnetic disk drive having a
At the part between the circuit board and the core holder.
Tilt the stator core in one direction with a spacer
The salient pole of the data core and the magnet in the thrust direction of the drive magnet
It is characterized in that the relationship with the pole center is non-parallel.

[0009]

According to the present invention, the relationship between the salient poles of the stator core and the magnetic center of the drive magnet in the thrust direction is non-parallel. Are tilted in one direction, and the center axis is also tilted and pressed in one direction in the radial direction of the bearing.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetic disk drive according to the present invention will be described below with reference to the drawings. In FIG. 1, a hole is formed in the center of the circuit board 6, and a cylindrical bearing holder 12 is attached to the hole. A flange 12 a is formed on the outer periphery of the bearing holder 12, and the lower surface of the flange 12 a is in contact with the upper surface of the circuit board 6. The upper and lower two bearings 8 are attached to the center through hole of the bearing holder 12. As the bearings 8, 8, a sintered oil-impregnated type bearing is used, and the center shaft 7 is inserted through these two bearings 8, 8 so as to be rotatable.

As shown in FIG. 2, a stator core 4 having a plurality of salient poles integrated radially is attached to an outer peripheral surface of the bearing holder 12 below the circuit board 6.
The drive coil 3 is wound around each salient pole of the stator core 4. A core holder 5 is interposed between the stator core 4 and the circuit board 6, and the upper surface of the core holder 5 and the circuit board 6
A spacer 11 having a trapezoidal cross section is attached to a part of the lower surface. For this reason, the core holder 5 is attached in a form inclined in one direction, and the stator core 4 attached to the lower surface of the core holder 5 is also inclined in one direction like the core holder 5. Screws are inserted through the stator core 4, the core holder 5, and the circuit board 6.
a, and the stator core 4, the core holder 5, and the circuit board 6 are pressed against the flange 12a by the head of the screw. They are fixed together.

A flange 7 a is formed at a lower end of the center shaft 7. A cup-shaped rotor case 2 is fixed to the lower surface of the flange portion 7a by screws 13. A cylindrical drive magnet 1 is attached to the inner surface of the peripheral wall of the rotor case 2. The inner peripheral surface of the drive magnet 1 faces the salient poles of the stator core 4 with a gap in the circumferential direction . Therefore, the rotor case 2 is energized by controlling the energization of the coil 3 wound around the salient pole, and
Central shaft 7 Ru is rotated to. On the other hand, the upper end of the central shaft 7 Ru is placed a magnetic recording medium such as a floppy disk
Hub table 9 is fitted.

The magnetic disk drive having the above-described configuration has a configuration in which the core holder 5 and the stator core 4 are inclined by interposing the spacer 11 in a part between the circuit board 6 and the core holder 5. The relationship between the salient poles formed on the outer periphery of the stator core 4 and the magnetic pole center 10 of the drive magnet 1 in the thrust direction is non-parallel over substantially the entire circumference. Therefore, the magnetic pole center 10 of the drive magnet 1 in the thrust direction with respect to each salient pole of the stator core 4 at each rotational position moves, and as a result, the magnetic attraction between each salient pole of the stator core 4 and the drive magnet 1 in the thrust direction. Since a difference in force is provided, it is possible to prevent a wobble or rattling of the central shaft 7 when the central shaft 7 is rotationally driven. In addition, a special member such as a magnet is not required to incline the stator core 4, and the stator core 4 can be inclined only by the spacer 11 having a trapezoidal cross section, so that the cost can be reduced. The stator core 4
Instead of using the spacer 11 for tilting, the cross section of the core holder 5 may be directly formed in a trapezoidal shape as shown in FIG. 3, and the stator core 4 may be tilted in one direction . In this case, the cost can be reduced because the spacer 11 becomes unnecessary.

[0014]

[0015]

[0016]

[0017]

[Effects of the Invention] According to the present invention, the cross section of the core holder
By forming a trapezoidal
Spacer is interposed between the core holder and the part
As a result, the stator core is tilted in one direction, and the relationship between the salient poles of the stator core and the magnetic pole center in the thrust direction of the drive magnet is made non-parallel. Force acts in the direction that the rotor case tilts,
Since the center shaft is pressed in one direction in the radial direction of the bearing, it is possible to prevent the wobble and rattling when the center shaft rotates.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a magnetic disk drive according to the present invention.

FIG. 2 is a plan view of a stator core in the embodiment.

FIG. 3 is a sectional view showing an example of a core holder that can be used in the present invention.

FIG. 4Cross section showing an example of a conventional magnetic disk drive
FIG.

FIG. 5 is an enlarged sectional view of a main part of the same .

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Drive magnet 2 Rotor case 3 Coil 4 Stator core 5 Core holder 6 Circuit board 7 Central axis 8 Bearing 9 Hub stand 10 Magnetic pole center 11 Spacer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-70461 (JP, A) JP-A-63-224654 (JP, A) JP-A-4-21147 (JP, U) JP-A-4-197 124863 (JP, U) JP-A-63-143054 (JP, U) JP-A-2-57275 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02K 29 / 00,21 / 00 H02K 5/15

Claims (2)

(57) [Scope of request for utility model registration] 1. A rotor case having a cylindrical drive magnet, a stator core having a coil wound around salient poles facing the inner peripheral surface of the drive magnet in the circumferential direction, and the stator core mounted via a core holder. A circumferentially opposed magnetic disk comprising a circuit board to be mounted, a bearing for rotatably supporting the central shaft, and a hub table fitted to one end of the central shaft and mounted with a magnetic disk for driving. In the driving device, the cross section of the core holder is formed in a trapezoidal shape, and the
A magnetic disk drive device characterized in that the core is inclined in one direction and the relationship between the salient poles of the stator core and the center of the drive magnet in the thrust direction is non-parallel. 2. A rotor case having a cylindrical drive magnet, a stator core having a coil wound around salient poles facing the inner peripheral surface of the drive magnet in the circumferential direction, and the stator core mounted via a core holder. A circumferentially opposed magnetic disk comprising a circuit board to be mounted, a bearing for rotatably supporting the central shaft, and a hub table fitted to one end of the central shaft and mounted with a magnetic disk for driving. In the driving device, a space is provided in a part between the circuit board and the core holder.
A magnetic disk drive device characterized in that the stator core is inclined in one direction with a rotor interposed therebetween so that the relationship between the salient poles of the stator core and the center of the drive magnet in the thrust direction is non-parallel.