JPH0612778A - Spindle motor for driving disk - Google Patents

Abstract

PURPOSE:To execute sure setting of a disk, reduction in thickness and simultaneous magnetization of magnets. CONSTITUTION:A rest surface 9a for the disk is formed on a rotor 9 mounted to a revolving shaft 6 and the magnet 20 for attracting the disk is mounted to the surface facing the disk to reduce the thickness. The N and S magnetic poles of the magnet 20 for attracting the disk are provided with >=4 pairs and the disk is set to a normal position by acting magnetic suction in case of the inclination of the disk. The magnetic poles of the rotor magnet 10 are provided with the number of poles corresponding to the magnetic poles of the magnet 20 for attracting the disk so that the simultaneous magnetization of the magnets 10, 20 is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive spindle motor for attracting and rotating a disk which is an information recording medium.

[0002]

2. Description of the Related Art In a magneto-optical recording apparatus, information is recorded and reproduced while rotating a disc, and a spindle motor for driving the disc is used for this purpose. FIG. 5 shows a conventional disk drive spindle motor, which includes a stator 51 including a stator coil 52 and a stator core 53.
Is attached to a bracket 54, and a rotary shaft 56 is rotatably supported by the bracket 54 via a ball bearing 55. A disc receiving member 57 extending in the radial direction is attached to the rotating shaft 56 so as to rotate integrally, and a rotor 58 is attached to the disc receiving member 57. The disk receiving member 57 is the disk 6
A receiving surface 57a that abuts 0 to support the disc 60 is formed on the outer peripheral side, and a disc attracting magnet 62 is attached to a portion of the inner peripheral side facing the disc 60 via a yoke 59. There is. On the other hand, the rotor 5
8 is attached to the disc receiving member 57 so as to be on the opposite side of the disc attracting magnet 62. The outer peripheral side of the rotor 58 is bent to the side opposite to the disk 60, and the rotor magnet 63 is attached to the bent portion 58 a and faces the stator 51. The disk 60 has a shaft hole 6 into which the shaft end 56a of the rotary shaft 56 is inserted.
In addition to having 0a in the central portion, a yoke 61 (disc yoke 61) is provided at a portion facing the disc attracting magnet 62.

FIG. 6 shows a disk attracting magnet 62, which is magnetized so that N and S magnetic poles form two pairs. On the other hand, the rotor magnet 63 is magnetized so that the N and S magnetic poles are 6 to 12 pairs. After the magnets 62 and 63 have been magnetized, the rotor magnet 63 is attached to the rotor 58, and the disc attracting magnet 62 is attached to the disc receiving member 57.

In the spindle motor having such a structure,
The shaft end portion 60a of the rotary shaft 56 is provided in the shaft hole 60a of the disk 60.
And the disc 60 is inserted into the disc receiving member 5
By being set in close contact with the receiving surface 57a of No. 7, a loop-shaped magnetic field is generated by the disk attracting magnet 62, the yoke 59, and the disk yoke 61. As a result, an effective magnetic attraction force acts on the disk 60, and stable rotation can be performed.

[0005]

However, when the disk 60 is set, if the shaft end portion 56a of the rotary shaft 56 and the peripheral portion of the shaft hole 60a of the disk 60 come into contact with each other, the disk 60 is tilted. Figure 7 shows this state,
Depending on the inclination of the disc 60, the disc attracting magnet 6
Since the second N pole is separated from the disc yoke 61 by a large distance A, the attraction force of the loop magnetic field of the disc attraction magnet 62 is insufficient. As a result, the disk 60 is not in the normal set state, and there is a problem that it cannot rotate. On the other hand, it is conceivable to increase the magnetic force by increasing the size of the disk attracting magnet 62, but in this case, there is a demerit that a large output is required when the disk 60 is ejected and the operability is reduced.

In the conventional spindle motor, the rotor 58, the disk receiving member 57 and the yoke 59 are interposed between the rotor magnet 63 and the disk attracting magnet 62.
Since it is provided in an assembled state, there is a limit to thinning. Moreover, even if the rotor 58, the disk receiving member 57, and the yoke 59 are integrated, the rotor magnet 63 and the disk attracting magnet 62 have different magnetic pole numbers, so there is a problem in magnetizing them.
This is because, when both magnets 62 and 63 are magnetized at the same time, the magnetizing fields influence each other and the magnetizing magnetic force cannot be effectively applied. For this reason, it is conceivable that either one of the magnets 62 or 63 is magnetized independently and then assembled to the motor. In this case, not only the magnetic force of the magnet is reduced but also magnetized. There is an inconvenience that the subsequent handling becomes troublesome.

The present invention has been made in consideration of these circumstances, and it is possible to stably magnetically attract a disk, reduce the thickness of the entire disk, and perform good magnetization. An object of the present invention is to provide a disk driving force spindle motor.

[0008]

In order to achieve the above object, a disk drive spindle motor according to the present invention faces a stator and a disk receiving surface formed on a rotor attached to the end of a rotary shaft. As described above, the rotor magnet is attached to the rotor, and the disc attracting magnet is attached to the surface of the rotor facing the disc. The disc attracting magnets are attached so that the N and S magnetic poles are four pairs or more. Characterized by being magnetized.

In this case, the magnetic poles of the rotor magnet can be made to correspond to the magnetic poles of the disk attracting magnet.

[0010]

In the above structure, since the magnetic poles of the magnet for attracting the disk are composed of four or more pairs, even if the disk tilts at the time of setting, one of the magnetic poles approaches the disk to form a magnetic field loop, so that the magnetic attraction. Power works effectively. Therefore, the disc can be brought into a normal set state. In addition, the receiving surface of the disk is formed on the rotor, the disk is directly supported by the rotor, and the disk attracting magnet is directly attached to the rotor, so that the thickness can be reduced. Furthermore, when the magnetic poles of the rotor magnet are magnetized so as to correspond to the magnetic poles of the disk attracting magnet, it is possible to perform simultaneous magnetization without mutual influence and to magnetize with a large magnetic force.

[0011]

1 shows an embodiment of the present invention in which a stator 1 consisting of a stator coil 2 and a stator core 3 is mounted on a bracket 4. A rotary shaft 6 is rotatably supported by the bracket 4 via a ball bearing 5. Reference numeral 7 is a retaining ring fitted to the rotating shaft 6 for preventing the ball bearing 5 from coming off.
A pair of ball bearings 5 are provided on the left and right, and a spring 8 is interposed between the ball bearings 5.
The spring 8 applies a preload to the ball bearing 5 to prevent the ball bearing 5 from rattling. Although this spring 8 has a coil shape, it has a small diameter in the vicinity of the center of its spring length and has substantially the same dimensions as the outer diameter of the ball bearing 5 at both ends. It doesn't happen.

A rotor 9 extending in the radial direction is attached to the shaft end of the rotary shaft 6. The rotor 9 is attached by press-fitting the shaft end portion of the rotary shaft 6, so that the rotor 9 and the rotary shaft 6 rotate integrally. In the present embodiment, the rotor 9 also functions as a disc receiving member that supports a disc (not shown), so that a flat receiving surface 9a protruding in the disc direction is formed on the outer peripheral side of the rotor 9. ing. Further, the outermost peripheral portion of the rotor 9 is bent in the direction opposite to the disc, and the rotor magnet 10 is attached to the bent portion 9b to face the stator 1. Further, a concave portion 9c is formed at a portion facing the disc on the inner peripheral side of the rotor 9, and the disc attracting magnet 20 is attached to the concave portion 9c via an adhesive to face the disc 7. Since the rotor 9 has the disc receiving surface 9a and the disc attracting magnet 20 as described above, the disc receiving member and the yoke of the disc attracting magnet 20 are not required. For this reason, it is possible to reduce the thickness, reduce the number of parts, and facilitate the assembly. Reference numeral 31 denotes a flexible circuit board attached to the bracket 4, and a sensor 32 for detecting the magnetic pole of the rotor magnet 10.
Is mounted at a portion facing the rotor magnet 10.

FIG. 2 shows a disk attracting magnet 20 having four pairs of magnetic poles of N pole 21 and S pole 22.
It is arranged radially. These four pairs of magnetic poles are magnetized by being magnetized after the disk attracting magnet 20 is attached to the rotor 9. By using four pairs of magnetic poles for the disc attracting magnet 20, even if the disc is tilted, one of the magnetic poles approaches the disc, so the distance between the adjacent magnetic poles and the disc becomes small (FIG. 7). (See distance B in). Therefore, the magnetic field loop of the magnetic pole attracts the disc, and the disc is set in a normal state and can rotate. Further, since the number of magnetic poles is large, the number of magnetic field loops on the disk is large, and stable setting of the disk is also possible. The number of magnetic poles of the disk attracting magnet 20 is not limited as long as it is four pairs or more.

FIG. 3 shows the arrangement of the disk attracting magnet 20 and the rotor magnet 10 in the rotor 9. The magnetic pole 11 of the rotor magnet 10 is arranged so as to form a magnetic field loop that is orthogonal to the magnetic field loop formed by the magnetic poles 21 and 22 of the disk attracting magnet 20.
The number of magnetic poles is the same as the number of magnetic poles of the disk attracting magnet 20 (four pairs in this embodiment), and is arranged on the extension line of the magnetic pole of the disk attracting magnet 20. In this way, by making the magnetic poles of the rotor magnet 10 correspond to the magnetic poles of the disk attracting magnet 20, the magnets 10 and 20 are magnetized at the same time.
Moreover, it can be carried out in a good condition without mutual influence.

FIG. 4 shows both magnets 10 and 20.
Showing the magnetized state, the rotor magnet 10 and the disk attracting magnet 20 are attached to the rotor 9 in which the shaft end of the rotary shaft 6 is press-fitted. In this state, the magnetizing yoke is attached to the magnets 10 and 20. 35 and 36 approach each other and magnetize them. At the time of this magnetization, since the rotor magnet 10 and the disk attraction magnet 20 are separately magnetized so as to correspond to each other, both magnets 10 and 20 can be magnetized simultaneously.

[0016]

As described above, according to the present invention, since the magnetic poles of the disk attracting magnet are four pairs or more, the disk can be set to a normal state even if the disk is tilted, and the rotor is provided with the disk attracting magnet. It can be made thinner. Further, since the magnetic poles of the rotor magnet have the number of poles facing the magnetic poles of the disk attracting magnet, they can be magnetized simultaneously without mutual influence of magnetic forces.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

2A and 2B are a front view and a side view showing magnetic poles of a disk attracting magnet.

FIG. 3 is a front view showing magnetic poles of a rotor magnet.

FIG. 4 is a sectional view showing magnetization.

FIG. 5 is a sectional view of a conventional spindle motor.

FIG. 6 is a front view and a side view of a conventional disk attracting magnet.

FIG. 7 is a sectional view showing a set of disks.

[Explanation of symbols]

 1 stator 6 rotating shaft 9 rotor 10 rotor magnet 20 disk adsorption magnet

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 25, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

In the spindle motor having such a structure,
The shaft end portion 60a of the rotary shaft 56 is provided in the shaft hole 60a of the disk 60.
And the disc 60 is inserted into the disc receiving member 5
By being set in close contact with the receiving surface 57a of No. 7 , a strong magnetic field in a loop shape is generated by the disk attracting magnet 62, the yoke 59, and the disk yoke 61 .
As a result, the disc 60 is fixed to the disc receiver and can be stably rotated.

Claims (2)

[Claims] 1. A receiving surface of a disc formed on a rotor attached to the end of a rotary shaft, a rotor magnet attached to the rotor so as to face the stator, and an opposing face of the rotor facing the disc. A spindle motor for driving a disk, characterized in that the magnet for attracting the disk is magnetized so that the N and S magnetic poles of the magnet for attracting the disk are 4 pairs or more. 2. The disk drive spindle motor according to claim 1, wherein the magnetic poles of the rotor magnet are magnetized so as to have the same number of poles as the magnetic poles of the disk attraction magnet.