JPH06284631A - Motor - Google Patents

Abstract

PURPOSE:To provide a motor in which the cost can be reduced in the grooving work while enhancing the accuracy, and the structure can be simplified while prolonging the service life. CONSTITUTION:The motor comprises a fixed stator section 10, a rotor section 20 rotatable with respect to the stator section 10 without touching the stator section 10, and groove sections 30 made in the opposing faces 11a, 21a of the rotor section 20 and the stator section 10 in order to the gaps with a lubrication fluid 100. The groove sections 30 are formed of coating layers 31, 35 of low friction material applied onto the opposing faces 11a, 21a of the rotor section 20 and the stator section 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor, for example,
The present invention relates to a spindle motor used in recording / reproducing devices for hard disks.

[0002]

2. Description of the Related Art A motor of this type has, for example, a stator portion fixedly installed in the main body of a hard disk recording / reproducing apparatus, and a rotor portion rotatably attached to the stator portion. The rotor portion is rotated in a non-contact state with the stator portion by the repulsive force of the magnet and the coil attached to the stator portion and the rotor portion, respectively.

A groove having a predetermined shape is formed on each of the facing surfaces of the stator portion and the rotor portion, and a fluid such as gas flows into the gap between the stator portion and the rotor portion by the groove portion. Due to the interposition of the fluid, a lubricating action and a bearing action between the stator portion and the rotor portion are performed.

Conventionally, such a groove portion has been formed by directly processing a metal base material forming a stator portion and a rotor portion. Specifically, the groove is etched by etching the metal base material. Further, the groove portion is formed by melting the surface of the metal base material with a laser or rolling the metal base material.

[0005]

However, in such a motor, since the technique of directly engraving the groove portion on the metal base material is adopted, the processing cost for forming the groove portion becomes high, and the groove portion is formed. However, there was a problem that the processing accuracy of was inferior.

That is, the technique for etching the metal base material is not suitable for mass production because it requires many steps for etching and the processing cost is high. Also,
In the technology of melting the metal base material surface by laser, the processing energy by laser is too large,
Machining becomes unstable, large burrs are generated at the edges of the groove, and the accuracy deteriorates.

Further, in the technique of rolling the metal base material, there is a problem in that the precision of the burrs on the edges of the groove and the groove depth are difficult to manage and the accuracy is poor. Further, since a groove is formed in the contact portion between the rotor portion and the stator portion, and the groove portion is engraved in the high friction metal base material forming the rotor portion and the stator portion, at the time of starting the rotation of the rotor portion. Therefore, the rotor part receives a large friction resistance. Therefore, there is a drawback that not only a large torque is required at the time of starting the rotation of the rotor portion, but also the life of the device is shortened due to wear.

This is particularly remarkable in the high rotation type gas lubrication motor. In order to prevent this, it is necessary to install special parts such as levitation magnets so that the rotor part does not contact the stator part at the time of starting and stopping, or to make special processing to make unevenness to reduce the contact surface. However, there is a problem that the manufacturing cost of the device is inevitably high.

The present invention has been made in order to solve the above problems, and provides a motor capable of reducing the cost of machining a groove portion, improving the machining accuracy and prolonging the life of the apparatus, and simplifying the apparatus structure. The purpose is to

[0010]

SUMMARY OF THE INVENTION In the present invention, the above-mentioned object is to provide a stator part, a rotor part rotatable in a non-contact state with the stator part, and the rotor part and the stator part. In a motor having a groove portion formed on either of the facing surfaces and allowing a lubricating fluid to flow through a gap defined by the facing surfaces, the groove portion is formed on one of the facing surfaces of the rotor portion and the stator portion. It is achieved by a motor formed of a coating layer of a low friction material coated on.

[0011] Preferably, the coating layer is a thrust receiving coating layer formed on one of the facing surfaces of the rotor portion facing each other in the rotational axis direction, and the facing layer facing the radial direction of the rotating shaft. It can be configured with a radial receiving coating layer formed by coating on any of the surfaces.

Further, preferably, the thrust receiving coating layer comprises a plurality of convex grooves spiraling in correspondence with the rotating direction of the rotor portion, and the radial receiving coating layer extends along the rotating direction of the rotor portion. It can be configured to have a plurality of substantially V-shaped concave grooves that are concavely provided.

The thrust receiving coating layer is provided on the facing surface of the stator portion, and the radial receiving coating layer is provided on the facing surface of the rotor portion.

[0014]

According to the above structure, when the rotation of the rotor is started,
The facing surfaces of the rotor portion and the stator portion are in contact with each other through the groove portion, but since the groove portion is formed of a low friction material,
The rotor part starts to rotate with a small torque and hardly wears. After the rotation is started, the groove for the coating layer having a high shape accuracy allows the lubricating fluid to accurately flow through the gap, and the rotor rotates in a non-contact state with the stator.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the examples described below are suitable specific examples of the present invention, and therefore, various technically preferable limitations are given, but the scope of the present invention particularly limits the present invention in the following description. Unless otherwise stated, the present invention is not limited to these modes.

In FIG. 1, a motor 1 is a high-speed rotation type spindle motor used, for example, in a hard disk recording / reproducing apparatus. The rotor portion 20 is rotatable in contact with the rotor portion 20, and the groove portion 30 that allows the lubricating gas 100 to flow in the gap between the stator portion 10 and the rotor portion 20.

The stator portion 10 has a structure in which a base substrate 17 forming an electric circuit is fixed to the outside of a cylindrical metal sleeve 11. A shaft insertion hole 12 for inserting a spindle shaft 21, which will be described later, is formed on the central axis of the sleeve 11. A lower end portion (lower end portion in FIG. 1) of the shaft insertion hole 12 is set to have a larger diameter than an upper portion thereof, so that a step 13 is formed.

A wide board mounting portion 14 is formed on the outside of the lower portion of the sleeve 11, and a base board 17 is mounted and fixed on the board mounting portion 14. Base substrate 17
Is fixed on the board mounting portion 14 while being fitted into the sleeve 11 via the large-diameter center hole 18. Then, on the surface thereof, the stator coil 1 forming the electromagnet is formed.
9 is formed. By energizing this stator coil 19 to form a magnetic field, a magnet 2 to be described later is formed.
It is supposed to give 8 a repulsive force.

On the other hand, the rotor portion 20 has a structure in which a magnet yoke 26 is connected to a metal spindle shaft 21 via a metal boss 23. The spindle shaft 21 is rotatably inserted in the shaft insertion hole 12 with the upper end portion (upper end portion in FIG. 1) protruding from the sleeve 11. A retaining member 22 is attached to the lower end of the spindle shaft 21, and the retaining member 22 and the step 13 are engaged with each other to prevent the spindle shaft 21 from detaching toward the upper end side.

The boss 23 is fixed to the upper end of the spindle shaft 21 through a center hole 24, and a gas circulation hole 25 having a diameter larger than that of the upper end of the sleeve 11 is formed in the lower central part of the boss 23. Has been done.

The magnet yoke 26 is fixed to the lower surface of the boss 23. Specifically, the magnet yoke 26 has a downward bowl shape, and is attached in a state in which a central hole 27 having substantially the same diameter as the gas flow hole 25 is aligned with the gas flow hole 25. Then, the magnet 28 is attached to the lower surface of the magnet yoke 26, and the FG is formed on the peripheral edge of the lower end.
(Freqency Ganerator) Magnet 29 is attached.

The magnet 28 is the stator coil 1
The magnetic force of 9 causes a repulsive force to rotate the rotor portion 20, and a plurality of rotor coils are provided corresponding to the stator coils 19. The FG magnet 29 also has a function of detecting the number of rotations of the rotor section 20. . The stator portion 10 and the rotor portion 20 of the motor 1 are configured as described above, and the groove portion 30 which is the main portion of this embodiment.
Is configured as follows.

As shown in FIG. 1, the groove portion 30 is composed of a thrust receiving coating layer 31 and a radial receiving coating layer 35. The thrust receiving coating layer 31 is provided on the upper surface 1 of the sleeve 11 that faces the lower surface 23 a of the boss 23 in the rotation axis L direction of the spindle shaft 21.
A coating is formed on 1a.

Specifically, as shown in FIGS. 2 and 3,
The coating layer 31 for receiving the thrust is the spindle shaft 2
The upper surface 1 of the sleeve 11, which is swirled in correspondence with the rotating direction of 1.
1a is a plurality of convex grooves 32 extending from the outer edge toward the shaft insertion hole 12 in the central portion. That is, the thrust receiving coating layer 31 is interposed between the sleeve 11 and the boss 23, and the gas 100 above the sleeve 11 is inserted into the shaft insertion hole 12 through the gap between the convex grooves 32 as shown by the arrow in FIG. It has the function of guiding inside.

On the other hand, the radial receiving coating layer 35
Is the sleeve 1 in the radial direction of the rotation axis L of the spindle shaft 21.
Surface 21 of spindle shaft 21 facing inner surface 11b of
The coating is formed on a. Specifically, as shown in FIGS. 4 and 5, the radial receiving coating layer 3
The reference numeral 5 is provided between the sleeve 11 and the spindle shaft 21, and has a plurality of substantially V-shaped recessed grooves 36 which are recessed along the circumferential direction of the surface 21a of the spindle shaft 21.

These thrust receiving coating layers 31
The radial receiving coating layer 35 is formed of a low friction material, and as the low friction material, for example,
Fluorine-based resin, especially Teflon-based resin is used.

Further, the thrust receiving coating layer 31
The radial receiving coating layer 35 masks the non-coated portions of the convex grooves 32 and the concave grooves 36, and the upper surface 11a of the sleeve 11 as the base material and the spindle shaft 21.
It is formed by coating the surface 21a of the. It can be also formed by coating the surfaces of the sleeve 11 and the spindle shaft 21 and then peeling off the non-coated portions of the convex grooves 32 and the concave grooves 36.

Since the groove portion 30 is formed by coating in this manner, the thrust receiving coating layer 31 and the radial receiving coating layer 35 can be easily processed in a small number of steps, and the convex groove 32 and the concave portion 32 can be formed. No burr is generated on the edge of the groove 36. Therefore, the groove 3
The processing cost of 0 can be reduced and the convex groove 32 and the concave groove 3 can be reduced.
It is possible to improve the processing accuracy of No. 6.

Next, the operation of the motor 1 will be described.
In FIG. 1, when the stator coil 19 of the stator portion 10 is energized, the magnetic force generated in the stator coil 19 and the magnet 28 interact with each other to cause the magnet yoke 26 to move.
The spindle shaft 2 that rotates and is connected through the boss 23.
The shaft 1 starts to rotate in the shaft insertion hole 12 of the sleeve 11.

At the time of such rotation start, the lower surface 23a of the boss 23 and the thrust receiving coating layer 31 are in contact with each other, and the inner surface 11b of the sleeve 11 and the radial receiving coating layer 35 are in contact with each other. ,
Friction resistance may occur with respect to the rotation of the spindle shaft 21 and the boss 23.

However, the thrust receiving coating layer 3
Since both 1 and the radial receiving coating layer 35 are formed of a low friction material, frictional resistance due to the coating layers 31 and 35 with respect to the rotation of the spindle shaft 21 and the boss 23 hardly occurs. Therefore, the spindle shaft 21 and the boss 23 start to rotate smoothly. That is, since the thrust receiving coating layer 31 and the radial receiving coating layer 35 function as a lubricant at the time of rotation start, the rotor portion 10 rotates at a high speed with a small torque and has low friction properties. Is
The life of the motor 1 is long because it hardly wears at the start of rotation.

After the rotation start, as shown by the arrow in FIG.
The external gas 100 enters through the gap between the lower end of the magnet yoke 26 and the base substrate 17, and the magnet yoke 26
Into the gas circulation hole 25 of the boss 23. Then, it enters the shaft insertion hole 12 of the sleeve 11 through the convex groove 32 of the thrust receiving coating layer 31, passes through the shaft insertion hole 12, and is discharged to the outside of the motor 1.

At this time, the convex groove 32 is, as described above,
The convex groove 32 has a spiral shape corresponding to the rotation direction of the spindle shaft 21 and is formed from the outer edge of the upper surface of the sleeve 11 toward the shaft insertion hole 12.
Has a pumping effect on the gas 1 in the gas flow hole 25
00 is forced to flow into the shaft insertion hole 12. Then, the gas 100 in the shaft insertion hole 12 is pressure-wise discharged from the shaft insertion hole 12 to the outside of the motor 1 by the pump effect of the substantially V-shaped concave groove 36.

As a result, the gas 100 becomes the gas flow hole 25.
The gas 100 smoothly circulates in the shaft insertion hole 12, and the space between the sleeve 11 and the boss 23 and the space between the sleeve 11 and the spindle shaft 21 are lubricated by the gas 100.

Further, due to the rotation of the concave groove 36, a dynamic pressure effect is produced, and the spindle shaft 21 is radially weighted by this dynamic pressure effect. Therefore, the spindle shaft 21 rotates in a non-contact state with the sleeve 11 around the central axis of the shaft insertion hole 12. Further, since the boss 23 is subjected to an upward load due to the dynamic pressure effect of the convex groove 32, the entire rotor portion 20 floats against the load, and the boss 23 rotates in a non-contact state with the upper surface of the sleeve 11. That is, when rotating, the gas 100
Performs a so-called bearing action on the rotor portion 20.

As described above, according to the motor 1 of this embodiment, the thrust receiving coating layer 31 and the radial receiving layer 31 which can be easily formed between the metal sleeve 11 and the spindle shaft 21 and the boss 23 are provided. Since the coating layer 35 is interposed, the sleeve 1
1, it is possible to reduce the design load of the motor 1 and to reduce the cost without requiring special parts or processing for preventing the wear of the spindle shaft 21, the boss 23.

[0037]

As described above, according to the present invention, since the groove portion is formed of the coating layer, the groove portion can be processed in a small number of steps, and burrs do not occur at the edge of the groove portion. Therefore, it is possible to reduce the cost of processing the groove portion and improve the processing accuracy. Further, since this coating layer is formed of a low friction material, even if the rotor portion and the stator portion come into contact with each other when the rotor portion starts rotating, there is almost no resistance due to friction. Therefore, the rotor portion can be rotated at a high speed with a small torque, and the contact portion between the rotor portion and the stator portion is hardly worn, so that the life of the device can be extended. Furthermore, since no special parts or processing are required to prevent wear of the contact portion between the rotor portion and the stator portion, the design burden of the device can be reduced and the cost of the device can be reduced.

[Brief description of drawings]

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

FIG. 2 is a plan view showing a thrust receiving coating layer.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a front view showing a radial receiving coating layer.

5 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 10 Stator part 11 Sleeve 11a Sleeve upper surface 20 Rotor part 21 Spindle shaft 21a Spindle shaft surface 30 Groove part 31 Thrust receiving coating layer 35 Radial receiving coating layer 40 Gap 100 Gas

Claims (4)

[Claims] 1. A stator part, a rotor part rotatable with the stator part in a non-contact state, and a rotor part formed on either of the facing surfaces of the rotor part and the stator part. In a motor having a groove portion for allowing a lubricating fluid to flow through the gap, the groove portion is formed of a coating layer of a low friction material coated on one of the facing surfaces of the rotor portion and the stator portion. A motor. 2. A coating layer for thrust receiving, which is formed on any one of the facing surfaces of the rotor portion that face each other in the rotation axis direction, and the facing surface that faces the radial direction of the rotation axis. 2. The motor according to claim 1, further comprising a radial receiving coating layer formed on any one of the above. 3. The thrust receiving coating layer,
It is composed of a plurality of convex grooves that swirl in correspondence with the rotation direction of the rotor portion, and the radial receiving coating layer has a plurality of substantially V-shaped concave grooves provided along the rotation direction of the rotor portion. The motor according to claim 2, wherein the motor has one. 4. The thrust receiving coating layer,
The motor according to claim 2 or 3, wherein the motor is provided on the facing surface of the stator portion, and the radial receiving coating layer is provided on the facing surface of the rotor portion.