JPH0631469A - Shaft working device for dynamic pressure bearing - Google Patents

Abstract

PURPOSE:To easily and inexpensively form a groove on a surface of a shaft for a dynamic pressure bearing. CONSTITUTION:Grooves 13, 14 are formed by rotating a shaft 3 with a motor, scanning and irradiating laser beams 9, 10 to the outer circumference and the end surface of the shaft 3 respectively from laser beam oscillators 7, 8 through beam scanners 11, 12. At this time, the grooves 13, 14 of the prescribed pattern are formed by detecting the rotation angle of the motor 1 with an encoder 5, and controlling a flashing of the laser beam oscillators 7, 8 and rotary angles of the beam scanners 11, 12 with a controller 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machining device for a shaft for a dynamic pressure bearing used in, for example, a spindle motor of a hard disk drive (HDD), and more particularly to a shaft machining device for a dynamic pressure bearing for grooving the shaft surface. Regarding

[0002]

2. Description of the Related Art In a dynamic pressure bearing used for a spindle motor of an HDD, a shaft is supported by an oil-impregnated bearing and rotates in a non-contact state by the pressure of oil. Therefore, it has less acoustic noise than the ball bearing, has the effect of extending the life, and has a simple structure and is suitable for downsizing. A groove for holding oil is formed on one of the surfaces where the shaft and the bearing face each other. Then, conventionally, a groove is formed on the surface of the shaft by an etching method or a rolling method, and a groove is formed on the inner peripheral surface of the bearing by the rolling method. For example, in the case of forming a groove on the outer circumference of the shaft by a rolling method, as shown in FIG. 8, a cylindrical die 51 having a convex portion 51a of a predetermined pattern formed on the outer circumference thereof is provided in parallel with a covered die. The groove 52a was formed by press-contacting the outer periphery of the shaft 52, which is a workpiece.

[0003]

However, when the groove is formed by the etching method, it is difficult to pattern the resist on the cylindrical surface, which is not suitable for mass production. Also,
The rolling method has drawbacks such as wear of the die and poor processing accuracy. Therefore, the conventional method for manufacturing a dynamic pressure bearing results in high cost, and thus has not been widely used as a rotary bearing.

The present invention has been made in view of the above circumstances, and a shaft for a dynamic pressure bearing in which a groove can be easily and inexpensively formed on the surface of a shaft rotatably supported by an oil-impregnated bearing. An object is to provide a processing device.

[0005]

According to a first aspect of the present invention, there is provided a dynamic pressure bearing shaft forming apparatus, wherein a dynamic pressure forming groove 13 or 14 is formed on a surface of a shaft 3 rotatably supported by oil-impregnated bearings 21 and 22. In a shaft processing apparatus for bearings, a motor 1 as a driving means for rotationally driving a shaft 3, laser light oscillators 7, 8 as laser light oscillating means for oscillating laser light 9, 10 and laser light 9, 10 are used as shafts. 3 Beam scanners 11 and 12 as scanning means for scanning the surface, blinking control of the laser light oscillators 7 and 8 in conjunction with rotation of the motor 1 and the beam scanner 11,
12 is provided, and a control device 6 as a control means for forming grooves 13 and 14 having a predetermined pattern on the surface of the shaft 3 is provided.

In the shaft processing apparatus for a dynamic pressure bearing according to a second aspect, the beam scanner 11 scans the laser beam 9 in the direction of the center line of the shaft 3.

The shaft processing apparatus for a dynamic pressure bearing according to a third aspect is characterized in that the beam scanner 12 scans the laser beam 10 in the radial direction of the shaft 3.

[0008]

In the shaft processing apparatus for a dynamic pressure bearing according to claim 1, the shaft 3 is rotationally driven by the motor 1 and the laser beams 9 and 10 are oscillated from the laser beam oscillators 7 and 8 to generate the beam scanner 11. By irradiating the surface of the shaft 3 with 12 and scanning, grooves 13 and 14 are formed on the surface of the shaft 3.
Can be formed. At this time, the control device 6 interlocks with the rotation of the motor 1 to blink the laser light oscillators 7 and 8 and control the rotation angles of the beam scanners 11 and 12, so that a predetermined pattern of 13 is formed on the surface of the shaft 3. , 1
4 can be formed.

In the hydrodynamic bearing shaft machining apparatus of the second aspect, the beam scanner 11 scans the laser beam 9 in the direction of the center line of the shaft 3 to form the groove 13 on the outer periphery of the shaft 3. You can

In the hydrodynamic bearing shaft machining apparatus according to the third aspect, the beam scanner 12 scans the laser beam 10 in the radial direction of the shaft 3 to form the groove 14 on the end face of the shaft 3. it can.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the shaft machining apparatus for a dynamic pressure bearing of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of the present invention. One end of a shaft 3 finished to a specified size is concentrically mounted on a rotary shaft 2 of the motor 1 via a mounting member 4. The rotary shaft 2 of the motor 1 is provided with an encoder 5 for detecting a rotary angle, and a signal of the rotary angle of the rotary shaft 2 detected by the encoder 5 is input to the control device 6.

On the other hand, high power laser light oscillators 7 and 8 are provided facing the outer circumference and the other end of the shaft 3, respectively.
Laser beams 9 and 10 respectively oscillated from the laser beam oscillators 7 and 8 are scanned by the beam scanners 11 and 12 at high speeds within the ranges of angles θ1 and θ2, respectively. The laser light oscillator 7,
The blinking of 8 and the rotation angles of the beam scanners 11 and 12 are controlled by the control device 6 by a predetermined program in association with the rotation angle signal sent from the encoder 5. Then, grooves 13 and 14 having a predetermined pattern are formed on the outer circumference and the end surface of the shaft 3.
To form.

FIG. 2 shows the operation when the V-shaped groove 13 is formed. When the shaft 3 rotates in the arrow X direction and the beam scanner 11 scans the laser light 9 in the Y direction, the laser light oscillator 7 is turned on only when the laser light 9 irradiates the range A, and the other portions are turned on. The groove 13 having a predetermined shape can be formed by turning off the irradiation. In this way, a plurality of grooves 13 as shown in FIG. 3 are formed on the outer periphery of the shaft 3. Similarly, the beam scanner 1
The groove 14 as shown in FIG. 4 is formed by scanning the end surface of the shaft 3 in the radial direction of the shaft 2.

5 to 7, the groove 1 is formed as described above.
An example in which a dynamic pressure bearing is configured using the shaft 3 on which 3, 14 are formed is shown. In the example shown in FIG. 5, grooves 13 and 14 are formed on the outer circumference and the flat end surface of the shaft 3, respectively, and the sintered oil-impregnated bearings 21 and 22 are opposed to the outer circumference and the end surface of the shaft 3 with a minute gap therebetween. It is a thing. And the shaft 3 has bearings 21, 22
On the other hand, the bearing 21 serves as a radial bearing and the bearing 22 serves as a thrust plane bearing by rotating without contact due to oil pressure.

The example shown in FIG. 6 shows a case where the end surface of the shaft 3 of the example shown in FIG. 5 is spherical, and the groove 14 is formed in the spherical surface, and the bearing 22 is a thrust spherical bearing.

In the example shown in FIG. 7, a flange 31 is provided on the shaft 3 at right angles to the axial direction, and a groove 14 is formed on the lower surface of the flange 31.
Is formed. The inner circumference of the bearing 21 serves as a radial bearing and the upper end surface serves as a thrust bearing.

According to this embodiment, the grooves 13 and 14 are formed on the outer circumference and the end surface of the shaft 3 for the dynamic pressure bearing by the laser beam processing, respectively, so that the processing can be performed easily and inexpensively. Further, since the spots of the laser beams 9 and 10 are small, the groove 3 having a complicated shape can be formed. Moreover, laser light can be easily processed even for hard materials,
The material of the shaft 3 can be freely selected.

[0019]

As described above, according to the shaft processing apparatus for a dynamic pressure bearing of the present invention, the groove is formed on the shaft by the laser beam, so that the processing can be performed easily and at low cost. it can. Moreover, it is easy to form a groove having a complicated shape, and the shaft material can be freely selected.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing the configuration of an embodiment of a shaft processing apparatus for a dynamic pressure bearing of the present invention.

FIG. 2 is an explanatory view showing a groove machining operation by the shaft machining apparatus shown in FIG.

3 is a development view showing an example of the shape of a groove formed on the outer circumference of the shaft of FIG. 1. FIG.

4 is a plan view showing an example of the shape of a groove formed on the shaft end surface of FIG. 1. FIG.

5 is an explanatory diagram showing a configuration of a first example of a dynamic pressure bearing using a shaft machined by the shaft machining device shown in FIG. 1. FIG.

6 is an explanatory diagram showing a configuration of a second example of FIG.

FIG. 7 is an explanatory diagram showing the configuration of the third example of FIG.

FIG. 8 is an explanatory diagram showing an example of a conventional shaft groove machining method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 motor (driving means) 3 axis 6 control device (control means) 7,8 laser light oscillator (laser light oscillation means) 9,10 laser light 11,12 beam scanner (scanning means) 13,14 groove 21,22 oil-impregnated bearing

Claims (3)

[Claims] 1. A shaft processing apparatus for a dynamic pressure bearing, wherein a groove is formed on a surface of a shaft rotatably supported by an oil-impregnated bearing, comprising: a driving unit that rotationally drives the shaft; and a laser light oscillating unit that oscillates a laser beam. Scanning means for scanning the shaft surface with the laser light; blinking control of the laser light generating means and operation control of the scanning means in conjunction with rotation of the driving means, and a predetermined pattern on the shaft surface. And a control means for forming the groove, the shaft processing apparatus for a dynamic pressure bearing. 2. The shaft processing device for a dynamic pressure bearing according to claim 1, wherein the scanning means scans the laser light in the direction of the center line of the shaft. 3. The shaft processing apparatus for a dynamic pressure bearing according to claim 1, wherein the scanning means scans the laser beam in the radial direction of the shaft.