JP2554943Y2 - Spindle motor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a spindle motor mounted on an optical / magnetic disk drive for rotating a recording disk.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view of a spindle motor for rotating a magnetic disk as a recording disk, for example. In FIG. 3, a predetermined number of magnetic disks a are mounted on a bowl-shaped hub member b. A pair of ball bearings m and n are mounted on both ends of the shaft c which is a stationary member, and via the ball bearings m and n (actually, a space member h is further interposed on the n ball bearings). And the hub member b is rotatably supported. Then, by the electromagnetic action of the armature e and the field magnet f, the hub member b
Are driven to rotate relative to.

[0003] Usually, the spindle motor is provided with a seal device for preventing unclean air existing in the motor internal space d from flowing out of the motor, ie, into the disk room space p. In FIG. 3, a labyrinth seal g configured by combining annular members j and k having protruding portions is provided outside the ball bearings m and n. In this labyrinth seal g, a minute gap r generated by an annular member j fixed to the shaft c side and an annular member k arranged opposite thereto and fixed to the hub member b side,
The motor internal space d and the disk indoor space p communicating with this
Are substantially sealed.

[0004]

However, in order to provide such a labyrinth seal g in a spindle motor, it is necessary to finish the above-mentioned annular members j and k to a required processing accuracy, and to provide them with high precision. Must be assembled to hub member b and shaft c. Otherwise, not only a sufficient sealing function cannot be obtained, but also a problem such as displacement or lock due to rotation of the spindle motor is involved. For this reason, corresponding care must be taken in parts management or assembly, and these factors have increased production costs. On the other hand, there is a means using a magnetic fluid sealing device, but there is a problem of scattering of the injected magnetic fluid and a relatively high cost of parts itself. doing.

[0005] The present invention has been made in view of the above-mentioned facts, and the problem is that a reliable and high sealing performance can be obtained even with relatively easy processing accuracy and assembling. An object of the present invention is to provide a spindle motor with high productivity and reliability that can be secured.

[0006]

In order to achieve the above object, a spindle motor according to the present invention comprises a bowl-shaped hub member on which a recording disk is mounted, a cylindrical stationary member,
Between the hub member at each end of the stationary member.
And a pair of ball bearings provided on the stationary member.
An armature provided between a pair of ball bearings and an outer periphery of the armature
And a field magnet provided on the inner periphery of the hub member facing the hub member.
And, in a spindle motor in which the hub member is driven rotates relative to the stationary member, the rotation axis direction of該玉bearing
The inner peripheral surface of the outer hub member rotates together with the hub member.
The annular member to be mounted is attached ,
The stepped portion that comes into contact with the outer periphery of the outer ring end surface of the ball bearing projects
The stepped portion is formed between the ball bearing and the annular member.
A radial gap is defined further inward, and
Between the inner peripheral surface of the annular member and the outer peripheral surface of the stationary member.
Defines a minute gap in the rotation axis direction communicating with the radial gap
Is, the inner and outer portions in the rotation axis direction of the annular member, is a substantially sealed to the labyrinth seal, and between該径direction
On the outer peripheral portion of the gap, the annular member, the step portion, the outer ring end surface,
An annular concave portion surrounded by is formed .

[0007]

[0008]

[Function] A minute gap in the rotation axis direction defined by the annular member.
Forms a labyrinth seal through which fluid cannot pass. I
The radial gap defined by the annular member is
Even if unclean air such as lubricant flows out, the rotation of the hub
As the centrifugal force accompanying the movement pushes back toward the step
And the unclean air passes outside the spindle motor
It flows in the direction away from the minute gap in the direction of the rotation axis. This
In the case of, dust fines contained in the unclean air pushed back
The child is held in the annular recess. Therefore, rotation of the annular member
Axial inner and outer parts are minute gaps and annular recesses in the rotation axis direction.
From the ball bearing by two radial gaps including
Unclean air flowing out diffuses out of the spindle motor
Can be prevented. Furthermore, the annular member has a step
High-precision positioning to avoid contact with the inner ring of the ball bearing
To form a radial gap . Therefore,
Sufficient sealing performance can be obtained even if the member that generates the labyrinth seal does not have a complicated shape as in the related art. Therefore, the machining accuracy and the assembling accuracy involved are not required to be so high, and a spindle motor with high yield and high productivity can be obtained.

[0009]

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a spindle motor according to the present invention will be described with reference to FIGS. FIG.
As an embodiment of the present invention, a spindle motor for driving a recording disk (for example, a magnetic disk) is shown in a sectional view. In FIG. 1, reference numeral 2 denotes a bowl-shaped hub member, which is formed of, for example, an aluminum material. The donut-shaped recording disk 1 is mounted on the flange portion 36 of the hub member 1. The recording disk 1 is sequentially connected to the recording disk 1 via a ring-shaped spacer member 8.
The sheets are stacked and mounted, and the clamp member 9 is mounted on the uppermost part.

The clamp member 9 has a substantially disk shape, and is screwed into a hole 14 provided in the hub member 2 by a mounting screw 13 and tightened. Thereby, the recording disk 1 is integrally held and fixed to the hub member 2. 3 is
The shaft is a stationary member, and is formed by processing, for example, an iron material. Both ends of the shaft 3 are fixed to a driving device (not shown) by screws or the like. A pair of ball bearings 4 and 5 as bearing members are fitted into the shaft 3, and the hub 2 is mounted via the ball bearings 4 and 5.
Specifically, the outer ring portion of the upper ball bearing 4 in FIG.
The outer ring portion of the lower ball bearing 5 is fixed to the inner peripheral surface 17 of the hub member 2 via the spacer member 15 formed in an annular shape. Is done.

A field magnet 7 having a cylindrical shape and magnetized to a required number of poles is adhered to a substantially central portion of an inner peripheral surface 17 of the hub member 2 via a yoke member 11 using a magnetic material. Have been. On the other hand, an armature 6 arranged opposite to the field magnet 7 is fitted into a substantially central portion of the shaft 3. The armature 7 is formed by laminating a required number of electromagnetic steel sheets, and is formed by winding a winding around a tooth part (not shown). A lead wire 12 is connected to the terminal of this winding,
This is led out of the spindle motor through a hole 32 formed in the shaft 3. When a required signal power is input to the lead wire, the hub member 2 is driven to rotate by the electromagnetic action of the armature 6 and the field magnet 7.

FIG. 2 is an enlarged sectional view of the periphery of the ball bearing 4 shown in FIG. This will be described with reference to FIG. Outside the ball bearings 4 and 5 in the spindle motor, that is, outside in the direction of the rotation axis 10, annular members 20 and 21 are provided. These annular members 20 and 21 are formed using, for example, an aluminum material or the like. As shown in FIG. 2, the annular member 20 located on the upper side of the spindle motor
2 is adhered to the inner peripheral surface 17 of the hub member 2.

The inner peripheral surface 25 of the annular member 20 is
Are opposed to each other so as to surround the outer peripheral surface 24, which is the surface of the, and both are arranged close to each other. FIG. 2 is a cross-sectional view in the direction of the rotation axis 10, which shows the inner peripheral surface 25 of the annular member 20 and the outer peripheral surface 24 of the shaft 3.
The minute gap 27, which is a minute gap in the rotation axis direction defined by the above, has a substantially rectangular shape. In this embodiment, the gap width t in the minute gap 27 is 0.05
mm, and the gap length L is set to 1.69 mm. The minute gap 27 functions as a labyrinth seal.

The lower surface 41 of the annular member 20 has a step 42
Are provided, and the lower surface of the step portion 42 and the outer ring portion 44 are provided.
(Ball bearing 4) The outer peripheral portion of the end face abuts, and positioning in the direction of the rotation axis 10 is performed. Also, by this step portion 42,
Between the upper surface 47 of the ball bearing 4 and the lower surface 41 of the annular member 20;
A gap portion 45 that is a radial gap portion is defined , and an annular portion is provided.
Annular recess surrounded by the material 20, the step portion 42, and the end surface of the outer ring portion 44
Part is Ru are defined. This gap 45 allows the annular member 20
Prevents contact with the inner ring 43. The gap 4
5 also has the following functions. That is, even if the lubricant contained in the ball bearing 4 flows out to the upper end, the lubricant is pushed back in the direction of the step 42 of the annular member 20 due to the centrifugal force due to the rotation of the hub member 2 , and the concave portion thereof is formed. Keep
Acts to be carried . Therefore, the unclean air containing the lubricant and the like does not easily diffuse to the outside 51 of the spindle motor via the minute gap 27 communicating with the gap 45.

On the other hand, the annular member 21 located on the lower side of the spindle motor is set to have the same shape and size as the annular member 20, and is positioned outward of the ball bearing 5 in the direction of the rotation axis 10. The annular member 21 has its outer peripheral surface 2
3 is fixed to the inner peripheral surface 16 of the spacer member 15. The inner peripheral surface 26 of the annular member 21 is provided close to and surrounds the outer peripheral surface 24 of the shaft 3. Similarly to the annular member 20, the annular member 21 and the outer peripheral surface 24 of the shaft 3 are provided.
Function as a labyrinth seal.

In this way, it is possible to effectively prevent the unclean air existing in the inner space of the spindle motor from escaping into the outer disk space 51. Minute gap 27,
28, the ratio of the gap length L to the gap width t, that is, L / t, is 33.
8 When the ratio is 30 or more, the effect of the labyrinth seal is further improved. Incidentally, the result of measuring the amount of dust scattered from the spindle motor of the present embodiment with a dust counter device is as follows.
An average of 135 m-sized dust particles occupied one cubic foot of space. On the other hand, in the conventional spindle motor of the same capacity shown in FIG.

As described above, one of the spindle motors according to the present invention is described.
Although the embodiment has been described, the present invention is not limited to the embodiment, and various changes and modifications can be made without departing from the scope of the present invention. For example, in the spindle motor of the present embodiment, in order to form the labyrinth seal, annular members 20, 2
Although the description is provided by providing two of one, at least one is provided,
If necessary, other sealing means may be used in combination. Also,
Although a ball bearing was used as the bearing member, the present invention is not limited to this, and a dynamic pressure bearing or other bearings may be used and can be selected freely.
In addition, the material used for the annular member can be freely designed.

[0019]

[Effect of the Invention] The spindle motor of the present invention is an annular member.
However, the inside and outside of the annular member in the rotation axis direction
Two gaps, a small gap and a radial gap including an annular recess
As a result, unclean air flowing out of the ball bearings
Can be prevented from spreading outside the data. In this case, the ring
The stepped part does not touch the inner ring of the ball bearing
Positioning to form a radial gap.
Wear. Therefore, the member that generates the labyrinth seal is
Sufficient sealing performance even without complicated shapes
can get. Therefore, the processing accuracy and assembly precision
The degree is not so high, and the yield is good.
Thus, a spindle motor having high productivity can be obtained.

[Brief description of the drawings]

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording disk 2 Hub member 3 Shaft (stationary member) 4 Ball bearing (bearing member) 5 Ball bearing (bearing member) 6 Armature 7 Field magnet 10 Rotation axis 20 Annular member 21 Annular member 27 Micro gap 28 Micro gap

Claims (1)

(57) [Scope of request for utility model registration] 1. A bowl-shaped hub member on which a recording disk is mounted, a cylindrical stationary member, and two ends of the stationary member.
A pair of balls respectively provided between the hub member
A bearing, provided between the pair of ball bearings in the stationary member;
Armature and the hub member facing the outer periphery of the armature.
And a field magnet provided on an inner circumference, the spindle motor in which the hub member is driven rotates relative to the stationary member, the inner peripheral surface of the hub member rotational axis outwardly of該玉bearing To
An annular member that rotates together with the hub member is mounted, and an inner ring end of the ball bearing is provided inside the annular member in the rotation axis direction.
A stepped portion that contacts the outer peripheral portion of the surface is formed so as to protrude.
Between the annular member and the radially inward of the step
A direction gap is defined, and the inner peripheral surface of the annular member and the
Rotation communicating with the radial gap between the stationary member and the outer peripheral surface
An axial minute clearance is defined , a labyrinth seal for substantially sealing the inside and outside of the annular member in the rotation axis direction is provided , and an outer peripheral portion of the radial gap includes the annular portion.
An annular recess surrounded by the material, the step, and the end surface of the outer ring is formed.
Spindle motor was, characterized in that.