JPH07236252A - Dynamic-pressure bearing turning gear - Google Patents

Abstract

PURPOSE:To enable stable operation at high speed for a prolonged term by forming a spirally formed dynamic-pressure groove to the outer circumferential surface of a shaft while mounting second and third magnets floating the shaft in the thrust direction and pivotally supporting the second and third magnets in a noncontact manner in the radial direction and the thrust direction. CONSTITUTION:A second magnet 29 and a third magnet 33 are constituted so as to be uniformly repulsed on a circumference, and equal clearances are obtained between each magnet 29, 33 both in the thrust direction and the radial direction. When a rotating magnetic field is generated by a first magnet 28 and a winding 33 under the state, a shaft 23 and a rotor section 26 are supported by a bearing 22 and tuned at high speed, and the shaft 23 is held in a noncontact manner in the radial direction to the bearing 22 by air pressure generated by a dynamic-pressure groove 24 at that time. Accordingly, the shaft 23 is floated, and can be operated at high speed without being brought into contact with the bearing 23, and the swing of the shaft 23 and the contact of the shaft 23 and the rotary bearing 22 at the time of start and stoppage can also be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic pressure bearing rotating device for bearing a rotary shaft in a radial direction in a non-contact manner by a dynamic pressure groove.

[0002]

2. Description of the Related Art A conventional dynamic pressure bearing rotating device is shown in FIG.
Those shown in are known. For example, a cylindrical bearing 2 is fixed to the central portion of a housing 1 having a cylindrical central portion, and a rotating shaft 3 rotating at high speed is rotatably held in the bearing 2. A spiral dynamic pressure groove 4 is provided on the outer peripheral surface of the rotary shaft 3 so that the rotary shaft 3 is held by the bearing 2 in a non-contact manner by the air pressure generated by the dynamic pressure groove 4 when the rotary shaft 3 rotates at high speed. Has become.

The lower opening of the housing 1 is closed by a closing member 5.
The thrust bearing 6 is provided inside the closing member 5, and the lower end of the rotary shaft 3 is rotatably supported by a pivot 7 provided on the thrust bearing 6.

A rotor portion 8 is integrally attached to the upper end side of the rotary shaft 3. In this rotor portion 8, a magnet 10 is attached to the lower surface of a disk-shaped rotor yoke 9, and, for example, a polygon mirror 11 is attached to the upper portion of the rotor yoke 9. A printed circuit board 12 is mounted on the upper end of the housing 1, and a flat winding 13 is mounted on the board 12 at a position facing the magnet 10.

[0005]

In such a conventional device, since the bearing in the thrust direction of the rotary shaft 3 is carried out by the pivot 7, the rotary shaft 3 and the thrust bearing 6 are contacted and worn by the pivot 7, and the long time is required. There was a problem that could not stand the operation. Further, since the bearing in the thrust direction is a contact type, there is a problem that the shaft vibration during rotation becomes large. Further, there is a problem that the rotor portion swings at the time of starting or stopping and the peripheral surface of the rotating shaft 3 comes into contact with the inner peripheral surface of the bearing 2 and wears.

Therefore, according to the present invention, bearings are contactless not only in the radial direction but also in the thrust direction, so that stable high-speed rotation can be maintained for a long time, and shaft vibration can be prevented. (EN) Provided is a hydrodynamic bearing rotating device capable of preventing contact wear of a shaft with a radial bearing.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a rotary shaft that rotates at a high speed, a bearing that rotatably holds the rotary shaft and performs radial bearings, a housing that supports the bearing, and a rotary shaft. A dynamic pressure groove formed in a spiral shape on the outer peripheral surface or on the inner peripheral surface of the bearing facing the outer peripheral surface, a rotor portion integrally provided on the rotary shaft, and rotating with the rotary shaft, and the rotor portion and the housing. First on one of the facing parts
Magnets and windings on the other side to generate a rotating magnetic field of the rotor part and a rotating magnetic field generating mechanism that repels each other on the circumference of the rotor part or the rotating shaft and the outer peripheral surface of the rotating shaft of the bearing. The second and third magnets are provided to levitate the rotating shafts with the same poles facing each other so as to face each other in the thrust direction.

[0008]

In the present invention having such a structure, the rotary shaft is floated in the thrust direction by the second and third magnets and the axial center is positioned. In this way, the bearing in the thrust direction is performed without contact. When a rotating magnetic field is generated by the rotating magnetic field generating mechanism in this state, the rotating shaft is supported by bearings and rotates at high speed. At that time, the rotary shaft is held in the radial direction in a non-contact manner with the bearing by the air pressure generated by the dynamic pressure groove. In this way, the radial bearing is also performed without contact.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a cylindrical bearing 22 is fixed to the central portion of a housing 21 having a cylindrical central portion, and a rotating shaft 23 rotating at high speed is rotatably held in the bearing 22. That is, the bearing 22 is a radial bearing.

The rotary shaft 23 is provided with a spiral dynamic pressure groove 24 on its outer peripheral surface. The lower opening of the housing 21 is closed by screwing a closing member 25. A rotor portion 26 is integrally attached to the upper end of the rotary shaft 23. The rotor portion 26 includes a first and second magnets 28, 28
29 is attached.

A polygon mirror 30, for example, is attached to the upper portion of the rotor yoke 27 by screwing. A printed circuit board 31 is mounted on the upper end of the housing 21, and a flat winding 32 is mounted on the lower surface of the board 31 at a position facing the first magnet 28. The first magnet 28 and the winding 32 constitute a rotating magnetic field generating mechanism.

Further, the second magnet 2 is provided at a position facing the second magnet 29 on the upper end of the bearing 22.
A disk-shaped third magnet 33 is attached such that the same poles as 9 face each other. That is, as shown in FIG.
A step portion 34 having a shorter outer peripheral side is provided along the circumference at the upper end of the bearing 22, and the third magnet 33 is provided on the step portion 34 so that the upper end surface of the magnet 33 is the circuit board 3.
It is attached so that it is flush with the upper end surface of 1.

The second magnet 29 has an S pole on the side in contact with the rotor yoke 27 and an N pole on the side facing the third magnet 33. The third magnet 33 has an N-side surface facing the second magnet 29.
It is a pole and the opposite side is an S pole. The distance between the second magnet 29 and the third magnet 33 is set so that the noise such as motor performance, the driving current, and the like show optimum values. Regarding the spacing, the second magnet 2
The effective areas for generating the magnetic fields of the ninth and third magnets 33 are changed and adjusted.

As shown in FIG. 3, the winding 32 includes, for example, six flat windings 321 to 326 and the circuit board 31.
In addition, they are arranged at equal intervals so as to be located on the circumference around the rotation shaft 23.

The first and second magnets 28 and 29 are composed of a common disk-shaped magnet member 35 as shown in FIG. 4, and the first magnet 28 has a circumference corresponding to the winding 32. Six N poles and S poles are alternately arranged on the upper side, and the second magnet 29 is formed inside the region of the first magnet 28 with all N poles on the circumference.

As shown in FIG. 5, the magnetizing method for forming the first and second magnets 28 and 29 on the magnet member 35 is such that a magnetic field is generated in the magnetizing yoke 36 in the direction in which the conductor 37 is desired to be obtained. The magnet member 35 is laminated on the magnetizing yoke 36, and the back yoke 38 is further laminated on the magnet member 35. Then, a large current is applied to the conductor 37 in the direction indicated by the arrow in the figure to generate a strong magnetic field. As a result, the magnet member 35 is
It will be magnetized as shown in.

In an embodiment having such a configuration, the second
Since the magnet 29 and the third magnet 33 repel each other, and further repel each other evenly on the circumference,
Each magnet 29 in both the thrust and radial directions
A uniform clearance can be obtained between the 33.

In this state, the first magnet 28 and the winding 3
When a rotating magnetic field is generated by 2, the rotating shaft 23 and the rotor portion 26 are supported by the bearing 22 and rotate at high speed. At this time, the rotary shaft 23 is held in the radial direction in a non-contact manner with the bearing 22 by the air pressure generated by the dynamic pressure groove 24.

As described above, the rotary shaft 23 is floated in the thrust direction by the repulsion of the second magnet 29 and the third magnet 33, and the axial center is positioned. Therefore, the rotary shaft 23 can rotate at high speed without contacting the bearing, and the run-out of the rotary shaft 23 and the contact between the rotary shaft 23 and the bearing 22 at the time of starting and stopping do not occur, and thus stable for a long time. The high-speed rotation can be maintained and the life can be extended.

Further, since the rotary shaft 23 does not come into contact with the bearing, the occurrence of shaft vibration can be prevented as much as possible, and the shaft vibration can be sufficiently reduced. Further, since the rotary shaft 23 also rotates without contact with the bearing 22, contact wear between the rotary shaft 23 and the bearing 22 can be prevented.

The magnetized shapes of the first magnet 28 and the second magnet 29 are not limited to those in the above embodiment, and may be the shapes shown in FIG. In the above embodiment, the first magnet 28 and the second magnet 28
Although the magnet 29 of the above is configured by the common magnet member 35, the present invention is not necessarily limited to this, and the first magnet 28 and the second magnet 2 are not limited thereto.
9 may be composed of separate magnet members.

In the above embodiment, the dynamic pressure groove 24 is formed on the outer peripheral surface of the rotary shaft 23. However, the present invention is not limited to this, and it is formed on the inner peripheral surface of the bearing 22. May be.

Further, although the second magnet 29 is attached to the rotor yoke 27 in the above embodiment, the present invention is not limited to this, and the second magnet 29 may be attached to the outer peripheral surface of the rotary shaft 23.

[0024]

As described in detail above, according to the present invention, since the bearing can be contacted not only in the radial direction but also in the thrust direction, stable high speed rotation can be maintained for a long time, and the shaft vibration can be maintained. It is possible to provide a dynamic pressure bearing rotating device capable of preventing the above-mentioned problem and preventing the rotating shaft from contacting and wearing the bearing in the radial direction.

[Brief description of drawings]

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

FIG. 2 is a partial cross-sectional view showing an enlarged main part configuration of the embodiment,

FIG. 3 is a diagram showing a configuration of a winding wire of the embodiment.

FIG. 4 is a diagram showing a configuration example of first and second magnets of the same embodiment.

FIG. 5 is a diagram showing a magnetizing method for obtaining the first and second magnets of the same embodiment.

FIG. 6 is a diagram showing another configuration example of the first and second magnets of the same embodiment.

FIG. 7 is a sectional view showing a conventional example.

[Explanation of symbols]

 21 ... Housing 22 ... Bearing 23 ... Rotating shaft 24 ... Dynamic pressure groove 26 ... Rotor part 28 ... First magnet 29 ... Second magnet 32 ... Winding 33 ... Third magnet

Claims (1)

[Claims] 1. A rotary shaft that rotates at high speed, and a bearing that rotatably holds the rotary shaft and performs radial bearings.
A housing supporting the bearing, a dynamic pressure groove formed in a spiral shape on the outer peripheral surface of the rotating shaft, or on the inner peripheral surface of the bearing facing the outer peripheral surface, and integrally provided on the rotating shaft. Rotating magnetic field generation for generating a rotating magnetic field of the rotor part by arranging a rotor part rotating with a rotating shaft and a first magnet in one of the facing parts of the rotor part and the housing and a winding in the other part. The mechanism and the rotor shaft having the same poles facing each other so as to repel each other on the circumference of the rotor portion or the rotary shaft and the outer circumferential surface of the rotary shaft of the bearing are levitated in the thrust direction. A hydrodynamic bearing rotation device comprising a second magnet and a third magnet.