JPH08205467A - Hydrodynamic bearing motor - Google Patents

Abstract

PURPOSE: To prevent flow-out of dust well with a simple structure at low cost. CONSTITUTION: An adhesive layer 40 for capturing dust is applied onto the wall face of a path communicating between a hydrodynamic bearing and the outer air. Dust being carried on the air flow from the hydrodynamic bearing to the outer air is captured by means of the adhesive layer 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air dynamic bearing motor which rotatably supports a fixed member and a rotary member by using the dynamic pressure of air.

[0002]

2. Description of the Related Art In recent years, polygon mirrors, magnetic disks,
Various proposals have been made for motors for rotating various rotary plates such as optical disks. As an example thereof, the basic structure of a motor having the air dynamic pressure bearing shown in FIG. 1 will be described. Although FIG. 1 shows a motor according to the present invention, since the basic structure of a conventional motor is also the same, description will be given based on this drawing.

That is, FIG. 1 shows an example of an air dynamic bearing type outer rotor type motor for rotationally driving a polygon mirror, and a stator set 2 as a fixed member assembled to the frame 1 side, A rotor set 3 as a rotating member is attached to the stator set 2 so as to be fitted from above in the drawing.
Of these, the stator set 2 has a fixed shaft 21 which is erected at a substantially central position of the frame 1, and a bearing holder 22 which surrounds the fixed shaft 21 in a cylindrical shape at a constant distance from the outer peripheral surface thereof. A stator core 23 is fitted on the outer circumference of the bearing holder 22. A drive coil 24 is wound around the salient pole portion of the stator core 23.

On the outer peripheral surface of the fixed shaft 21, a herringbone type dynamic pressure generating groove 25 is axially divided into two blocks and annularly recessed, and the dynamic pressure generating groove 2 is provided.
The cylindrical body 31 of the rotor set 3 is rotatably mounted on the outer side of the fixed shaft 21 on which the rotors 5, 25 are provided. Further, a dynamic pressure is generated between the outer peripheral surface of the fixed shaft 21 and the inner peripheral surface of the cylindrical body portion 31 of the rotor set 3 to form a radial bearing. Further, an air supply hole 26 extends in the axial direction from the shaft end portion (upper end portion in the drawing) of the fixed shaft 21, and the air supply hole 26 generates the dynamic pressure of the two blocks. Groove 2
The portion between 5 and 25 is open toward the outside of the fixed shaft 21.

Further, the shaft end portion (upper end portion in the drawing) of the fixed shaft 21 has an outer edge portion protruding in the axial direction by a predetermined amount, and a fixed side magnet 27 for thrust levitation is annularly formed on the inner peripheral wall of the protruding portion. It is installed. On the other hand, on the base side (upper end side in the drawing) of the cylindrical body portion 31 of the rotor set 3, a fine air orifice 32 having a predetermined air flow resistance is axially formed through the central portion thereof. , By the damper action of the air orifice 32, the rotor assembly 3
Axial impact on the is reduced.
Further, the air inside the rotor set 3 is fed to the portion between the dynamic pressure generating grooves 25, 25 by the air supply hole 26, and the pumping action of the dynamic pressure generating grooves 25, 25 causes the air pressure in the axially outer direction in the vertical direction in the figure. And is discharged to the outside.

In addition, around the air orifice 32,
A rotation-side magnet 33 for floating the thrust is attached in an annular shape. The rotating-side magnet 33 is magnetized in the axial direction (the vertical direction in the drawing) so as to mutually generate a magnetic attractive force with the fixed-side magnet 27 on the fixed shaft 21 side. The set 3 is configured to be held in a state of being floated by a predetermined amount in the thrust direction.

On the other hand, a flat surface hexagonal polygon mirror 34 as a rotating plate is fitted on the outer periphery of the cylindrical body 31 of the rotor set 3 on the base side (upper end side in the figure). The polygon mirror 34 is axially mounted on a holding portion 38 extending outward from the cylindrical body portion 31, and is fixed by a holding spring 39 which is a clamping means.

The rotor flange portion 35 has a cylindrical body portion 3.
1 is integrally formed with the rotor flange portion 35.
The outer peripheral portion of is arranged so as to face the polygon mirror 34 in the axial direction. That is, the rotor flange portion 35 is formed of a plate-shaped member that extends in the radial direction between the polygon mirror 34 and the drive coil 24, and is axially (downward in the drawing) from the outer peripheral portion of the rotor flange portion 35. A drive magnet 37 is annularly attached to an inner peripheral wall surface of an annular mounting plate 36 that projects toward.
The drive magnet 37 corresponds to the stator core 23 described above.
Are arranged so as to face the outer peripheral surface of the.

[0009]

However, in a motor provided with such an air dynamic pressure bearing, sufficient dynamic pressure cannot be obtained immediately at the time of starting and stopping, and rotation with the fixed side surface forming the bearing surface The sides may touch.
At the time of the contact, dust such as abrasion powder may be generated although the amount is very small. This dust moves along with the flow of air flowing out of the dynamic pressure air bearing to the outside air, and flows in the communication passage from the inside of the motor to the outside air. The dust that has flowed out of the motor adheres to the polygon mirror surface, for example, and causes a problem such as a decrease in reflectance. In particular, the rotary plate of a polygon mirror, a magnetic disk, an optical disk, or the like that requires cleanliness is driven to rotate. It is a serious problem in motors.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an air dynamic pressure bearing motor capable of satisfactorily preventing the outflow of dust with a simple and low cost structure.

[0011]

In order to achieve the above object, the present invention provides an air dynamic bearing motor having an air dynamic bearing that rotatably supports a fixed member and a rotary member by the dynamic pressure of air. In the above, the dust trapping adhesive layer is deposited on the wall surface of the passage communicating from the air dynamic pressure bearing to the outside air.
It has a formed structure.

[0012]

According to the present invention as described above, the dust flowing in the communication passage extending from the dynamic pressure air bearing to the outside air is captured by the adhesive layer for capturing dust, which is adhered to the wall surface of the communication passage,
Outflow to the outside is prevented.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. The overall structure of the motor shown in FIG. 1, which represents an embodiment of the present invention, has already been described in the section of the prior art, and therefore will be omitted, and the main part of the present invention will be described below.

As shown in FIG. 2, in the rotor set 3, the inner space A on the center side is defined by the inner wall surface of the base end portion (upper end portion in the drawing) of the cylindrical body portion 31 and the tip end surface of the fixed shaft 21.
In addition, the outer internal space B is defined by the outer peripheral surfaces of the rotor flange portion 35 and the cylindrical body portion 31, and the like. The center-side inner space A and the outer-side inner space B are in communication with the air dynamic pressure bearing portion, and the center-side inner space A is the air orifice 32.
Through to communicate with the motor outer space, and the outer inner space B also opens and communicates with the motor outer space.

As described above, the center side inner space A and the outer side inner space B form a communication passage communicating from the air dynamic pressure bearing to the outside air, and on the wall surface of each member forming the communication passage. An adhesive layer 40 for capturing dust is deposited and formed. As the adhesive used for the adhesive layer 40, various materials such as butyl acrylate, ether hexyl acrylate, natural rubber, synthetic rubber, and silicone rubber are adopted.
It is applied or spread by spraying.

As described above, in the apparatus of this embodiment, the dust that is about to flow out into the outside air by riding on the air flow from the air dynamic pressure bearing to the outside air is used to capture the dust deposited on the wall surface of the communication passage. It is captured by the adhesive layer 40 and is prevented from flowing out.

Further, in this embodiment, as shown in FIG. 3, uneven surfaces such as grooves, protrusions and steps are formed on at least a part of the wall surface on which the dust-trapping adhesive layer 40 is adhered and formed. Has been formed. In the case of this embodiment, the bearing holder 22
Although an uneven surface is formed on the inner peripheral wall surface of the cylindrical body 31
It is also possible to form another wall surface, such as the outer peripheral surface, on which the adhesive layer 40 is adhered and formed as an uneven surface. By providing such an uneven surface, the trapping action by the adhesive layer 40 can be performed more favorably.

Further, in this embodiment, the rotor flange portion 3
An adhesive layer 40 is adhered to and formed on the inner peripheral wall surface facing the center of rotation, such as the inner peripheral surface of the mounting portion 36 of FIG. Since they are collected, dust will be easily and efficiently captured.

Further, the dust-trapping adhesive layer 40 is also adhered to the outer surface of the drive coil 24 so that the dust originally attached to the drive coil 24 will not fall off or flow out.
It is prevented by 0.

Although the invention made by the present inventor has been specifically described based on the embodiments, the invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say. For example, the present invention can be similarly applied to a shaft rotation type motor, and further to a motor for rotationally driving various rotary plates such as magnetic disks and optical disks other than polygon mirrors.

[0021]

As described above, in the air dynamic pressure bearing motor according to the present invention, an adhesive layer for capturing dust is adhered on the wall surface of the passage communicating from the air dynamic pressure bearing to the outside air to obtain the dynamic pressure air bearing. Since it is configured to catch the dust that tries to flow out to the outside air by riding on the flow of air from the outside to the outside air, the outflow of dust can be satisfactorily prevented by the simple and low-cost structure. The reliability of the air dynamic pressure bearing motor can be improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional explanatory view showing an example of an air dynamic bearing motor to which the present invention is applied.

FIG. 2 is a semi-longitudinal sectional view showing an enlarged main part of the air dynamic pressure bearing motor shown in FIG.

FIG. 3 is a vertical cross-sectional view showing a further enlarged part III in FIG.

[Explanation of symbols]

 21 fixed shaft 24 drive coil 25 dynamic pressure generating groove 31 rotor cylindrical body portion 34 polygon mirror 35 rotor flange portion 36 mounting portion 40 adhesive layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H02K 29/00 Z

Claims (6)

[Claims] 1. An air dynamic bearing motor having an air dynamic pressure bearing that rotatably supports a fixed member and a rotary member by a dynamic pressure of air, in a passage communicating with the outside air from the air dynamic pressure bearing. On the wall,
An air dynamic bearing motor characterized in that an adhesive layer for capturing dust is adhered / formed. 2. The pneumatic dynamic bearing motor according to claim 1, wherein the wall surface on which the adhesive layer for capturing dust is adhered has an uneven surface. 3. The air dynamic bearing motor according to claim 1, wherein the wall surface to which the adhesive layer for trapping dust is adhered is an inner wall surface facing toward the center of rotation. Dynamic bearing motor. 4. The pneumatic dynamic bearing motor according to claim 1, wherein an adhesive layer for capturing dust is adhered to the outer surface of the drive coil. 5. The air dynamic bearing motor according to claim 1, wherein the dust trapping adhesive layer is adhered and formed by coating. 6. The air dynamic bearing motor according to claim 1, wherein the dust trapping adhesive layer is adhered and formed by spraying.