JPH04244756A - Spindle motor - Google Patents

Abstract

PURPOSE:To obtain a spindle motor in which the height of a body can be reduced while maintaining desired characteristics by omitting a sealing member of one side inner end of a bearing member. CONSTITUTION:An upper bearing member 31 for rotatably supporting a hub 1 is of a both side sealing type provided at both ends with sealing members 34, 35, and a lower bearing member 32 employs a one side sealing type provided only at an outer end with a sealing member 37. The member 35 of the member 31 is substantially used also as an inner sealing member to be provided at the member 32. Accordingly, its thickness can be reduced substantially without influence to characteristics.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor installed in, for example, an optical/magnetic disk device and used for rotationally driving a recording disk.
The present invention relates to a spindle motor suitable for driving small-sized recording disks such as 2.5-inch and 2.5-inch.

0002

2. Description of the Related Art A spindle motor used to drive a magnetic disk or the like rotates one or more disks as a load mounted on a hub. In recent years, equipment has become smaller,
With weight reduction, spindle motors are also forced to follow this trend.

FIG. 3 shows a cross-sectional view of a conventional spindle motor. FIG. 3 shows, for example, a spindle motor equipped with one 2.5-inch disk, where 1 is a hub, 2 is a bracket, 31 and 32 are bearing members, 4 is a stator, 5 is a rotor magnet, 6 is a disk, and 7 is a clamp member, and 8 is a mounting screw.

The disk 6 is attached to the hub 1, specifically held in a predetermined position by the outer peripheral surface 11 and flange 12 of the hub, and is held between the disk 6 and the hub 1 by a clamp member 7. Then, by screwing the mounting screw 8 into the female screw hole 13 of the hub 1, the clamp member 7 is fixed, and as a result,
The disk 6 is fixed to the hub 1.

[0005] The hub 1 is integrated with a shaft portion 17,
Further, it is rotatably supported by bearing members 31 and 32 mounted on the inner circumferential surface 22 of the cylindrical portion of the bracket 2 . On the other hand, a rotor magnet 5 provided inside the hub 1 and a stator 4 fixed to the outer peripheral surface 21 of the cylindrical part of the bracket 2
The hub 1 is rotated by the relative rotation thereof, and the disk 6 rotates together with the hub 1.

[0006]

By the way, in order to cope with the above-mentioned miniaturization and thinning, it is particularly required for spindle motors that the height dimension, that is, the thickness in the axial direction, be made as small as possible. However, there is a limit to reducing the distance between the bearing member 31 and the bearing member 32, and furthermore, scaling down the bearing member is difficult to change easily in order to maintain the rotational accuracy and rigidity of the spindle motor. This is difficult due to design.

The present invention has been made in view of the above facts, and its main purpose is to reduce the height of the main body while maintaining desired torque characteristics and necessary rotational accuracy and rigidity. Therefore, it is an object of the present invention to provide a spindle motor that can contribute to miniaturization of devices.

[0008]

[Means for Solving the Problems] According to the present invention, there is provided a bracket, a hub rotatable relative to the bracket, and a pair of bearing members interposed between the bracket and the hub. , a spindle motor comprising a rotor magnet attached to the hub, and a stator fixed to the bracket and disposed opposite to the rotor magnet, the spindle motor being rotationally driven by the relative rotation of the rotor magnet and the stator. In the spindle motor, there is provided a spindle motor characterized in that a seal member to be incorporated therein is not provided at one inner end of the pair of bearing members.

[0009]

[Operation] Since a sealing member to be included is not provided at the inner end of one of the bearing members, the thickness of the bearing member can be made smaller by the space required for this sealing member. As a result, the height dimension can be reduced without reducing the rigidity, and a thin spindle motor can be obtained.

Note that even if the corresponding sealing member is not provided, the sealing member included in the other end of the bearing member or the sealing member included in the other bearing member can prevent the grease, etc. contained in the bearing from being contained in the disc. It can prevent leakage and scattering into the room.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a spindle motor according to the present invention. FIG. 1 is a sectional view of a spindle motor equipped with, for example, one 2.5-inch disk. Note that the same numbers are given to the same members as those already explained in the conventional example of FIG. Further, the disk 6, clamp member 7, and mounting screw 8 are omitted because they are substantially the same.

In FIG. 1, a hub 1 is made of aluminum, stainless steel, etc., and includes a hub body 16 and a shaft 1.
7 are integrally formed. This makes it possible to downsize the spindle motor and improve its whirling accuracy with respect to the shaft center. Note that the hub body portion 16 and the shaft portion 17 may be formed separately and fixed together by press-fitting or the like.

A rotor magnet 5 is disposed on the inner peripheral surface of the hub 1, and a stator 4 is fixed to the outer peripheral surface 21 of the cylindrical portion 26 of the bracket 2 in opposition to the rotor magnet 5. In this motor, the shaft portion 1 of the hub 1 is
7 is rotatably supported, and an outer rotor type is adopted in which the rotor magnet 5 and the stator 4 are driven by relative rotation.

Coil wire 40 drawn out from stator 4
is connected to a printed circuit board 41 attached to the surface of the bracket 2, and an end of the printed circuit board 41 is led out of the spindle motor.

Referring also to FIG. 2, the upper bearing member 31 that rotatably supports the hub 1 is a double-side seal type bearing member in which seal members 34 and 35 are provided at both ends, and the lower The bearing member 32 is a one-side seal type bearing member in which a seal member 37 is provided only on the lower side in the figure, that is, on the outer end. The lower (inner) seal member 35 of the bearing member 31 substantially serves as the inner seal member to be provided on the lower bearing member 32.

Therefore, with respect to the center of the lower bearing member 32, the upper bearing member 31 is located on the upper side, that is, on the disk chamber side.
There are seal members 34 and 35 of the lower bearing member 32, and a seal member 37 of the lower bearing member 32 and a bearing protection cap 9 on the lower side with respect to the center, that is, on the outside side. Therefore, this sealing member prevents grease, etc. contained in the bearing member from flowing out or scattering to the inside or outside of the spindle motor, and by omitting some sealing members, the thickness of the bearing member increases in the height direction, that is, the thickness. can be made thinner. The space required for the seal member in the bearing member does not substantially affect the rigidity. Note that the seal members 34, 35,
37 can be formed from synthetic rubber.

In the spindle motor of this embodiment, in order to more effectively prevent the grease contained in the bearing member from diffusing into the space where the recording disk is accommodated and contaminating it, the following measures are taken. It has a structure. That is, a bearing protection cap 9 is attached to the bottom of the bracket 2 with an adhesive or the like to reliably prevent grease from scattering to the outside of the spindle motor, ie, below the bracket in the figure. On the other hand, this protective cap 9 seals the air communication between the inside and outside of the spindle motor and seals the inside of the motor, so that the grease of the bearing members 31 and 32 is kept in the space communicating with the recording disk chamber through the inside of the motor. No diffusion or leakage.

[0018] Furthermore, there is a labyrinth structure formed by a minute gap between the upper end of the outer ring 33 of the bearing 31 and the trapezoidal part 15 inside the hub 1;
The sealing performance is improved by a labyrinth structure formed by a minute gap between the outer peripheral inner circumferential surface 23 of the hub 1 and the outer circumferential end surface 14 of the hub 1 opposed thereto.

As described above, in the spindle motor of the present invention, since the seal member at the inner end of one of the pair of bearing members is omitted, the characteristics are not substantially affected and the thickness dimension can be reduced. Can be made thinner.

Although one embodiment of the spindle motor according to the present invention has been described above, the present invention is not limited to this embodiment, and various modifications and modifications can be made without departing from the scope of the present invention. be.

For example, in the embodiment, the lower bearing member 32
The upper (inner) seal member is omitted and the lower bearing member 3
Instead of this, the lower (inner) seal member of the upper bearing member 31 may be omitted to reduce the thickness of the upper bearing member 31. Furthermore,
In order to further reduce the height of the motor, the upper (inner) seal member of the lower bearing member 32 and the lower (inner) seal of the upper bearing member 31 may be omitted. Even if the seal member inside the pair of bearing members is omitted,
These outer seal members effectively prevent grease from scattering, and the effects of their omission can be minimized.

[0022]

Advantages of the Invention Since the present invention has the above-described configuration, it has the following effects. By omitting the sealing member of the bearing member, the thickness can be reduced while maintaining the required rigidity. Therefore, a spindle motor with a small height of the main body that maintains a high level of rotational accuracy can be obtained.

[Brief explanation of the drawing]

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

FIG. 2 is a partially enlarged view showing a part of the spindle motor in FIG. 1;

FIG. 3 is a sectional view showing a conventional spindle motor.

[Explanation of symbols]

1 Hub 2 Bracket 31 Bearing member 32 Bearing member 34 Seal member 35 Seal member 37 Seal member 4 Stator 41 Printed circuit board 5 Rotor magnet 6 Disc 7 Clamp member 8 Mounting screw 9 Bearing protection cap

Claims (1)

[Claims] 1. A bracket, a hub rotatable relative to the bracket, a pair of bearing members interposed between the bracket and the hub, and a rotor magnet attached to the hub. , a spindle motor comprising a stator fixed to the bracket and disposed opposite to the rotor magnet, and rotationally driven by relative rotation between the rotor magnet and the stator,
A spindle motor characterized in that a sealing member to be incorporated therein is not provided at one inner end of the pair of bearing members.