JPH1155900A - Spindle motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To positively prevent a rotator from being pulled out or floated by allowing a suction magnet being mounted to a locking piece to face the core of a coil winding assembly and allowing the locking piece to touch a bearing when the rotator moves. SOLUTION: A herringbone groove 8 is provided on a bearing 7 and a thrust plate 9 supports a rotary shaft 1 in axial direction. A bracket 4 retains the bearing 7. A coil winding assembly 6 is mounted to the bracket 4. Also, a locking piece 10 consisting of a magnetic material is mounted to a hub 2. A suction magnet 11 is fixed to the locking piece 10 and faces a core 12 of the coil winding assembly 6. With this configuration, even if vibration and shock are applied to a motor, the floating of the rotator is prevented by the suction force being generated between the attracting magnet 11 and the coil winding assembly 6. On the other hand, even if an excessive shock is applied, the pull-out of the rotator can be positively prevented by the sliding on the bearing 7 when the rotator moves in a thrust direction even if an excessive shock is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a disk drive spindle motor of a magnetic disk memory device mainly in the OA field.

[0002]

2. Description of the Related Art Conventionally, a magnetic disk spindle motor having a structure shown in FIG. 2 is known. FIG. 2 shows a structural example of a conventional spindle motor.

In FIG. 2, reference numeral 18 denotes a bracket.
The winding assembly 20 and the shaft 14 are fixed to the bracket 18. Reference numeral 15 denotes a bearing, which is fixed to a hub 16 as a rotating body by means such as press fitting. A thrust plate 17 is fixed to the hub 16 and supports the shaft 14 in the thrust direction. A rotor magnet 19 is fixed to the hub 16 and drives the motor.

[0004]

However, in the conventional example, especially when a vertical vibration or impact is applied to the motor,
The rotating body may fall off or move vertically from the shaft.

To solve such a problem, Japanese Utility Model Laid-Open Publication No.
The technique described in Japanese Patent No. 358 is known. A conventional example using the technique will be described with reference to FIG.

[0006] The same reference numerals are used for the same components as those in FIG. 2 and the description of the same components is omitted.

In FIG. 3, magnets 21 and 22 are magnets attached to the hub 16 and generate an attractive force between the magnets and the core of the winding assembly 20 to prevent the rotating body from coming off the shaft.

However, even if this technique is used, there is a limit in vibration resistance and shock resistance, and since the magnet 22 is located near the rotor magnet 19, it adversely affects the magnetic field for driving the motor. Difficult to configure.

[0009]

According to the present invention, there is provided a rotating shaft, a bearing for rotatably supporting the rotating shaft, a hub fixed to the rotating shaft, and a hub fixed to the hub. It consists of a retainer made of magnetic material, a suction magnet attached to the retainer, a bracket for holding the bearing, and a winding assembly fixed to the bracket. The suction magnet faces the core of the winding assembly. In addition, the stopper prevents the rotating body from coming off by coming into contact with the bearing when it moves.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a rotating shaft, a bearing for rotatably supporting the rotating shaft, a hub fixed to the rotating shaft, a retaining member made of a magnetic material fixed to the hub,
It consists of a suction magnet attached to the retainer, a bracket for holding the bearing, and a winding assembly fixed to the bracket, and the suction magnet is a spindle motor facing the core of the winding assembly, This has the effect of reliably preventing the rotating body from coming off or floating.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. It is to be noted that the same reference numerals are given to portions having the same configuration as the conventional example, and the description of the same portions is omitted.

In FIG. 1, reference numeral 1 denotes a rotating shaft. Reference numeral 2 denotes a hub fixed to the rotary shaft 1 by a method such as press fitting. 3
A frame 5 is attached to the hub 2 by a rotor magnet to form a rotating body. Reference numeral 7 denotes a bearing composed of a hydrodynamic bearing that rotatably supports the rotary shaft 1 in the radial direction. Reference numeral 8 denotes a herringbone groove provided in the bearing 7. Reference numeral 9 denotes a thrust plate for supporting the rotating shaft 1 in an axial direction. 4 is a bracket holding the bearing 7. A winding assembly 6 is attached to the bracket 4.

The hub 2 has a retaining member 10 made of a magnetic material. Reference numeral 11 denotes an attraction magnet fixed to the retaining member 10 and faces the core 12 of the winding assembly 6.

With this configuration, even if vibration or impact is applied to the motor, the floating body is prevented from floating due to the attraction force generated between the attraction magnet and the winding assembly. Also, when the rotating body moves in the thrust direction, it can be reliably prevented from coming off by slidingly contacting the bearing.

[0015] The retainer also serves as a shield for preventing magnetic flux leakage from the attraction magnet. Although the embodiment in which the bearing is constituted by a hydrodynamic bearing is described, it goes without saying that the same effect can be obtained even in a motor in which the bearing is constituted by a sintered oil-impregnated bearing.

[0016]

As described above, according to the present invention, there are obtained advantageous effects that the rotor can be prevented from coming off and floating, and the vibration of the motor in both the radial and axial directions can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a spindle motor according to the present invention.

FIG. 2 is a cross-sectional view of a conventional spindle motor.

FIG. 3 is a sectional view of another conventional spindle motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotating shaft 4 Bracket 6 Winding assembly 7 Bearing 10 Retaining 11 Attraction magnet 12 Core

Claims (3)

[Claims] 1. A rotating shaft, a bearing rotatably supporting the rotating shaft, a hub fixed to the rotating shaft, a stopper made of a magnetic material fixed to the hub, and attached to the stopper. Suction magnet, a bracket for holding the bearing, and a winding assembly fixed to the bracket, the suction magnet faces the core of the winding assembly, and the retainer is used when the rotating body moves. Spindle motor that only comes into sliding contact with the bearing. 2. The spindle motor according to claim 1, wherein the bearing comprises a hydrodynamic bearing provided with a herringbone groove or the like. 3. The spindle motor according to claim 1, wherein the bearing is a sintered oil-impregnated bearing.