KR200212473Y1 - Motor with leakproof structure - Google Patents

Abstract

The present invention is directed to a motor having a leakproof structure for preventing oil leakage through the top of the sleeve by arranging a plurality of grooves to allow air flow to be generated in a direction opposite to the direction of oil flowing out to the top of the sleeve. In order to achieve the above object, the present invention provides a small size that allows the rotating members of the rotor and the shaft to be rotated more smoothly from the fixing member consisting of the base and the sleeve by the fluid dynamic bearing consisting of the sleeve and the shaft. In the precision motor, a plurality of arc-shaped curved in the direction opposite to the rotation direction of the shaft to the upper end surface of the sleeve 10 facing each other spaced at a minute interval from the bottom surface of the shaft holder, which shaft 20 is inserted and fixed The groove 30 is characterized by a configuration that is radially recessed.

Description

Motor with leakproof structure

The present invention relates to a motor having a leakage preventing structure, and more particularly, to a motor to prevent oil leakage between the top surface of the sleeve and the shaft holder.

In general, small precision motors used in office equipment such as hard disk drives, laser scanning units, and digital video discs require inevitably high speeds and precisions. Most of them apply.

There are many types of such fluid bearings, but the most widely used fluid hydrodynamic bearings as shown in FIG. 5 to minimize the friction between contact surfaces by using the dynamic pressure effect of the fluid generated by the relative motion of the shaft and the sleeve. to be. That is, the sleeve 2 is axially fixed to the base 1, and the shaft 3 is formed in the center of the sleeve 2 to form a herringbone type or oblique type dynamic pressure groove 3a on the outer circumferential surface thereof. 3, the upper end part is fixedly fixed to the center part of the shaft holder 4b which was integrally provided in the rotor 4. As shown in FIG. The sleeve 2 is equipped with a stator core 2a wound around the outer circumferential surface, and the rotor 4 has a plurality of driving magnets 4a interacting with the stator core 2a on the inner circumferential wall of the lower end portion. To be attached. A fine gap (usually several micrometers) is formed between the inner circumferential surface of the sleeve 2 and the outer circumferential surface of the shaft 3, and oil is filled in the gap. The oil filled in the gap between the sleeve 2 and the shaft 3 acts as a wedge and generates dynamic pressure during the driving of the shaft 3 so that the shaft 3 is accurately supported at the center.

Therefore, when power is applied to the stator core 2a from the outside, the driving magnet 4a which interacts with it rotates, and the rotor 4 and the shaft 3, which are rotating members, also rotate simultaneously. At this time, the lower end of the sleeve (2) on which the shaft (3) is axially supported is normally sealed by the support (5), and the upper end is predetermined between the faces facing each other to prevent the surface friction with the shaft holder (4b), which is a rotating member. To be spaced apart.

However, as the shaft 3 rotates, the oil ejected from the gap between the sleeve 2 and the shaft 3 flows heavily, and as a result of centrifugal force, the inner circumferential surface of the sleeve 2 and the outer circumferential surface of the shaft 3 are rotated. Is raised to the upper end of the opened sleeve 2, and this synergism causes the shaft 3 to rotate at a high speed to increase the upward pressure so that the upper surface of the sleeve 2 and the shaft holder 4b There is a problem that a small amount of oil is leaked through the space between the bottom of the).

In particular, when the motor is driven for a long time, even if the amount of leakage is increased gradually, the oil shortage in the bearing is caused to shorten the service life of the motor, and as a result, the reliability of the motor may be reduced.

In order to improve the above-mentioned problems, the present invention contemplates grooves so that outside air flows in a direction corresponding to the direction in which oil flows out by the rotational force of the shaft to the upper surface of the sleeve, which is an oil outflow passage. The main purpose is to provide a motor that can be prevented.

In addition, the present invention has another purpose to form a spiral groove to the upper surface of the sleeve to provide a simpler sealing structure.

1 is a perspective view of an embodiment of an embodiment of the present invention;

2 is a plan view of the present invention,

3 is a plan view showing another embodiment of the present invention;

4 is a structural view of the operation of the present invention;

5 is a cross-sectional structure diagram of a conventional motor,

6 is a partial cross-sectional view showing a sleeve top surface coupling structure in a conventional motor.

<Description of the code | symbol about the principal part of drawing>

10: sleeve 11: the central hall

20: shaft 30: groove

In order to achieve the above object, the present invention provides a compact precision motor that allows the rotational members of the rotor and the shaft to be rotated more smoothly from a fixed member consisting of a base and a sleeve by a fluid dynamic bearing consisting of a sleeve and a shaft. In such a configuration, a plurality of grooves having an arc shape curved in a direction opposite to the rotational direction of the shaft are radially concave with the upper surface of the sleeve facing each other spaced at a minute interval from the bottom surface of the shaft holder into which the shaft is inserted and fixed. This is a feature.

Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a plan perspective view showing main parts of a preferred embodiment according to the present invention, wherein 10 is a sleeve. The sleeve 10 is a fixing member whose bottom part is fixed to a base, and the stator core wound by a coil is fixed to the outer peripheral surface at the end.

And the sleeve 10 is provided with a hole 11 penetrating through the center, the hole 11 is inserted into the shaft 20 having a small diameter is formed, in particular, the shaft 20 is the lower end of the sleeve The sliding of the shaft 20 is made possible by the oil applied to the upper surface of the support while being close to the upper surface of the support inserted from the lower end of the hole 11 to seal the bottom of the hole 11. have.

The present invention has a top surface of the sleeve 10, which is supported while the shaft 20 is inserted, that is, the upper surface of the shaft 20 is axially fixed and the corresponding surface finely spaced apart from the bottom surface of the shaft holder integrally provided with the rotor As the inner circumferential surface and the outer circumferential surface is in communication with each other so that a plurality of spiral grooves 30 are formed at regular intervals.

In other words, the groove 30 is formed such that a curved portion is formed in the opposite direction to the rotational direction of the shaft 20, as shown in FIG. 2, and the width of the groove 30 on the outer circumferential surface side is It is more preferable to form larger than the inner peripheral surface side, such as.

In addition, it is most preferable that the groove 30 has an acute angle from the main surface while the end of the inner peripheral surface of the sleeve 10 is inclined in the rotational direction of the shaft 20.

On the other hand, the spiral groove 30 in the top surface of the sleeve 10 to adjust the depth, angle and number according to the rotation speed and diameter of the shaft 20.

Referring to the operation of the present invention according to the above configuration, as described above, a plurality of driving magnets attached to the inner circumferential surface of the lower circumferential wall of the rotor and the stator core fixed to the outer circumferential surface of the sleeve while power is applied from the outside are applied to the interaction. To rotate the rotor. At this time, while the shaft holder integrally provided in the rotor rotates at the same time, the shaft fixed to the shaft holder is interlocked.

As shown in FIG. 4, when the shaft 20 rotates in the direction of the arrow in the central hole 11 of the sleeve 10, the end portion of the central hole 11 side concave on the top surface of the sleeve 10 is axially rotated. The phenomenon that the air is sucked toward the central hole 11 in the spiral groove 30 is formed to be caused. That is, if the end of the groove 30 on the center hole 11 is formed to face the rotational direction of the shaft 10, the air is discharged to the outside of the center hole 11 by the rotational force of the shaft 10. However, when the end of the groove 30 is formed in the rotational direction of the shaft 10 as in the present invention, the air in the center hole 11 continues to flow in the center hole 11, This causes the phenomenon that outside air is inhaled.

In particular, as shown in FIG. 3, the outer peripheral surface side groove 30 end of the sleeve 10 is formed to have a larger width than the inner peripheral surface side end, and as the rotational force of the shaft 10 increases, air into the central hole 11 increases. Since the suction force becomes stronger, the oil injected between the inner circumferential surface of the sleeve 10 and the outer circumferential surface of the shaft 20 is lifted by the centrifugal force and can no longer be lifted by the air suction force. Only flow inside).

As a result, unlike the conventional method of using a separate sealing means, by simply means of merely grooving the groove 30 on the top surface during the manufacture of the sleeve, it is possible to prevent further consumption of oil by blocking the outflow of bearing oil. To help.

On the other hand, the greater the driving force of the motor, the greater the rotational force of the shaft. Therefore, in the past, a separate sealing means provided as an upper portion of the sleeve only under a certain rotational force was able to serve as a function. Used to finely flow out.

However, in this design, the stronger the rotational force of the shaft is, the more the air suction force sucked from the center hole of the sleeve increases in proportion to the rotational force of the shaft. Will be.

This ensures that no matter how severe the flow of oil in the gap between the sleeve and the shaft prevents further oil leakage, the bearing can always maintain a stable motor drive with a certain amount of oil filled.

In particular, the present invention may be made by injection molding at the same time by the mold at the time of manufacture of the sleeve, it is possible to form a spiral groove by a separate simple processing immediately after injection to provide a more simplified sealing structure formation.

Therefore, the smooth operation of the motor by simply solving the sealing problem, which was considered to be the most difficult in a motor having a hydrodynamic bearing by the above-described design, by forming a plurality of spiral grooves on the upper surface of the sleeve. In addition to improving performance and durability, it provides a very useful effect of reducing workability and required parts and costs in manufacturing a motor.

Claims (3)

In a small precision motor that combines a fixing member consisting of a base and a sleeve and a rotating member consisting of a rotor and a shaft, Leak-proof structure to allow a plurality of grooves, which are arc-shaped, curved in the direction opposite to the rotational direction of the shaft to the upper surface of the sleeve facing each other spaced at a slight interval from the bottom of the shaft holder fixed to the shaft. Having a motor. The groove of claim 1, wherein the groove is A motor having a leak-proof structure in which the width of the outer peripheral surface side of the top surface of the sleeve is made larger than the width of the inner peripheral surface side. The groove of claim 1, wherein the groove is A motor having a leakage preventing structure in which an end portion of the inner circumferential surface side of the sleeve is inclined in the rotational direction of the shaft and has an acute angle from the main surface.