KR20040060903A - Fluid Dynamic Bearing Spindle Motor - Google Patents

Abstract

PURPOSE: A shaft-fixed-type fluid dynamic bearing motor is provided to achieve improved performance of rotor by increasing the number of platters so as to record a large capacity of data. CONSTITUTION: A shaft-fixed-type fluid dynamic bearing motor comprises a stator, and a rotor supported by the stator. The stator includes a housing(100) fixed at a lower fixing member(220); a shaft(140) having a lower end fixed at the center of the housing and a top fixed at an upper fixing member(210); a thrust plate(171) coupled to the top of the shaft; and a core(130) coupled to the lower end of the center of the housing. The rotor includes a sleeve(120) coupled to the shaft and supported by a fluid dynamic bearing motor in such a manner that the sleeve is rotatable; a cover block(170) coupled to the top of the sleeve, and which supports the sleeve in a thrust direction and has a fluid groove formed at the inner surface of the cover block so as to improve the pressure in the bearing; and a hub(150) coupled to the outer surface of the sleeve, and which has a magnet(160) arranged in the inner surface of the lower end of the hub in such a manner that the magnet is opposed to the core so as to form an electromagnetic circuit.

Description

Axis Fixed Fluid Hydraulic Bearing Motor {Fluid Dynamic Bearing Spindle Motor}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial fixed dynamic bearing spindle motor, and in particular, it can cope with a load load by employing a plurality of platters to record and / or record a large amount of information. The present invention relates to a fluid dynamic bearing motor whose structure is improved to minimize the temperature rise of the oil by effectively distributing heat generated during the driving of the motor.

In general, hydrodynamic bearings form a constant oil gap between the rotor and the stator of the motor, and fill the oil gap with oil of a certain viscosity to compress the oil filled by the oil gap during rotation of the rotor. To form a fluid dynamic pressure so as to rotatably support the rotor.

1 schematically shows an example motor employing a hydrodynamic bearing.

This shows an axial rotation type motor in which a shaft is rotated, and a stator composed of a housing 10, a sleeve 20, and a core 30, and a rotor composed of a shaft 40, a hub 50, and a magnet 60. Is made of.

The sleeve 20 is formed in a hollow shape so that the shaft 40 is rotatably inserted, and an oil groove (not shown) is formed in the inner diameter surface to generate dynamic pressure by introducing oil.

In addition, an annular thrust plate 70 is rotatably coupled to the lower end of the shaft 40 together with the shaft 40, and a core 30 to which a coil is wound is fixed to an inner center of the housing 10. It is installed.

Upper and lower surfaces of the thrust plate 70 are provided with a groove (not shown) for generating dynamic pressure so that fluid dynamic pressure in the axial direction is generated.

On the other hand, the cover plate 80 for rotatably supporting the lower end of the thrust plate 70 and the shaft 40 is coupled to the lower end of the sleeve 20.

The hub 50 is integrally coupled to the upper end of the shaft 40, and the hub 50 has a downwardly open cap shape and has a magnet facing the outer diameter surface of the core 30 on the inner diameter surface of the extension end. 60) is installed.

In the conventional axial rotating hydrodynamic bearing motor having the above configuration, when power from the outside is applied to the core 30, the magnet 60 is attached by mutual electromagnetic force between the core 30 and the magnet 60. The hub 50 is rotated so that the shaft 40 coupled with the hub 50 is rotated at the same time.

The shaft 40 rotatably coupled to the inner diameter portion of the sleeve 20 when the motor is driven is an oil groove (not shown) formed in the inner diameter surface 21 of the sleeve 20 or the outer diameter surface of the shaft 40. By the fluid dynamic pressure in the radial direction generated in the) it can be smoothly rotated in a non-contact state with the inner diameter surface 21 of the sleeve 20.

In addition, between the thrust plate 70, the sleeve 20, and the cover plate 80, a fluid dynamic pressure in the thrust direction is generated and rotated.

However, the motor employing the fluid dynamic bearing of the above structure has the following problems.

First, when a large capacity drive (HDD) is pursued by increasing the number of platters that are coupled to the hub 50 and rotated together, the load of the rotating body (hub and shaft) is increased and vibrations are generated. have.

Second, heat is generated by electromagnetic characteristics such as the core 30 and the magnet 60 when the motor is driven, and mechanical frictional heat is generated due to the relative speed between the rotor and the stator constituting the hydrodynamic bearing.

In particular, since the relative speed increases in the sleeve 20 and the thrust plate 70 having a larger diameter than the shaft, the heat generation is large. Therefore, the oil temperature rises due to the heat generation in the thrust plate 70 forming the hydrodynamic bearing surface, and as a result, the oil viscosity decreases, thereby reducing the load bearing capacity of the hydrodynamic bearing.

In addition, if the load bearing capacity is reduced, the gap between the hydrodynamic bearing surfaces becomes narrower, which causes additional heat generation.

In addition, since electromagnetic heat sources and heat sources caused by mechanical friction are adjacent to each other, oil deterioration deepens and shortens the life of the oil, and as a result, the oil viscosity as described above decreases the driving characteristics of the motor. .

The present invention was created to solve the above problems, and has the following object.

First, to provide a shaft fixed hydrodynamic bearing motor with improved load capacity of the rotor to increase the number of platters (platters) that are rotated together with the hub to pursue a large capacity drive (HDD) .

Second, it is to provide a fluid dynamic bearing motor capable of reducing the deterioration of the oil by minimizing the heat generated by separating the electromagnetic heat generating source and the heat generating source by mechanical friction.

1 is a cross-sectional view showing a conventional hydrodynamic bearing motor,

2 is a cross-sectional view showing the present invention shaft fixed hydrodynamic bearing motor;

3 is a cross-sectional view of the cover block.

* Explanation of symbols for main parts of the drawings

100 ... Housing 120 ... Sleeve

130 ... core 140 ... shaft

150 ... hub 160 ... magnet

171 Thrust Plate 170 Cover Block

210,220 ... upper and lower fixture 400 ... platter

The present invention to achieve the above object is a hydrodynamic bearing motor in which the rotor is rotatably supported by the hydrodynamic bearing relative to the stator,

The stator includes a housing fixed to the lower fixing body, a shaft fixed at the lower end to the center of the housing, and an upper end fixed to the upper fixing body, an annular thrust plate fixed to the upper end of the shaft, and the housing. A coil wound around the bottom of the central portion of the core,

The rotor is rotatably coupled to the shaft to be rotatably supported by a hydrodynamic bearing, and the cover is coupled to the upper end of the sleeve to support the sleeve in the thrust direction and to improve the pressure inside the bearing It is characterized in that it comprises a hub having a block and a magnet coupled to the outer periphery of the sleeve and rotated together and installed on the lower inner peripheral surface facing the core to form an electromagnetic circuit.

According to the features of the present invention, the hydrodynamic bearing motor of the present invention has a structure in which both ends of the shaft are fixed, so that when the weight of the rotating body such as an increase in the number of platters is increased, a conventional shaft is rotated at a higher speed Stiffness decrease due to rotation is prevented to enable stable driving. In addition, the fluid hydrodynamic bearing motor of the present invention makes it possible to smoothly discharge heat generated by separating heat generating source by electromagnetic elements such as core and magnet and heat generating source by mechanical friction between thrust plate and sleeve. Reduce the deterioration of

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

Since the shaft fixed type hydrodynamic bearing motor of the embodiment of the present invention is fixed at both ends of the shaft, a plurality of platters are mounted on the hub so that stable driving is possible despite large loads, and heat generation and mechanical friction caused by electromagnetic elements are possible. By separating the heat generating source by each other to facilitate the release of the generated heat.

In addition, by closing the upper end of the sleeve to which the shaft is rotatably coupled with the cover block to form a fluid dynamic pressure to increase the internal pressure of the hydrodynamic bearing portion and effectively prevent the leakage of oil.

These features of the present invention are described in detail in the following embodiments.

Referring to FIG. 2, which shows a hydrodynamic bearing motor of an embodiment of the present invention, it has a structure in which a rotor is rotatably supported by a hydrodynamic bearing with respect to a stator.

The stator includes a housing 100 fixed to the lower fixing body 220, a shaft 140 fixed to the lower end of the housing 100, and an upper end fixed to the upper fixing body 210, and the shaft. An annular thrust plate 171 coupled to an upper end portion of the 140 and a core 130 wound around a coil fixed to a lower end of a central portion of the housing 100 are provided.

The rotor is rotatably coupled to the shaft 140 to be rotatably supported by a hydrodynamic bearing, and coupled to an upper end of the sleeve 120 to thrust the sleeve 120. The cover block 170 supporting in the direction, and the magnet 160 is coupled to the outer periphery of the sleeve 120 and rotated together to be installed opposite the core 130 on the lower inner peripheral surface to form an electromagnetic circuit is It is provided with a hub 150 provided.

The upper and lower fixing bodies 210 and 220 may be, for example, cases of a hard disk drive.

A fluid groove (not shown) having a herringbone shape or a spiral shape is formed on the outer circumferential surface of the shaft 140 or the inner diameter surface of the sleeve 120 corresponding thereto to form a fluid between the sleeve 120 and the sleeve 120. Allow dynamic pressure to form.

In addition, a herringbone-shaped or spiral-shaped fluid groove is formed on an upper side, a lower side of the thrust plate 171 or an upper side of the sleeve 120 facing the same, and a fluid dynamic pressure is generated. It is.

The shaft fixed type hydrodynamic bearing motor of such a structure secures both ends of the shaft 140 having a smaller diameter and a longer length than other components, and has a small rigidity, and rotates the hub 150 on which a plurality of platters 400 are mounted. By using it as a whole, it prevents the occurrence of vibration etc. due to the decrease in rigidity by high speed rotation. In addition, by using the shaft 140 as a stationary body, it is possible to mount a plurality of platters 400 by increasing the rigidity, so that a large amount of information can be stored.

The hydrodynamic bearing motor is a sleeve 120 and the hub 150 and the magnet 160 for the stator consisting of the housing 100, the shaft 140 and the core 130 when power is applied to the core 130 The configured rotor is to be rotated relatively.

The oil filled between the fixed shaft 140 and the rotating sleeve 120 is concentrated in the fluid groove (not shown) to form a high pressure to form a hydrodynamic bearing in the radial direction.

In addition, a fluid dynamic bearing in a thrust direction is formed between the thrust plate 171 and the sleeve 120.

As described above, the shaft 140 is smoothly rotated by the hydrodynamic bearing in the radial direction and the hydrodynamic bearing in the thrust direction.

In addition, the oil pressure acts downward on the inclined groove 170a (see FIG. 3) formed on the inner diameter surface of the cover block 170 that is rotated, thereby increasing the internal pressure between the sleeve 120 and the shaft 140. And prevent oil leakage.

As such, when the hub 150 is rotated by the electromagnetic circuit between the core 130 and the magnet 160, fluid dynamic pressure is formed by oil filled on the oil gap between the sleeve 120 and the shaft 140. Thereby stably supporting the rotation of the hub 150.

In addition, the cover block 170 and the thrust plate 171, which generates mechanical frictional heat, are installed on the upper end of the shaft 140 to be separated from the electromagnetic frictional heat generating portion of the core 130 and the magnet 160. This facilitates the release of heat generated.

The present invention as described above may be practiced with many modifications without departing from the spirit and scope of the present application.

The present invention as described above has the following advantages.

First, by fixing both ends of the shaft 140, by using the hub 150 on which a plurality of platters 400 are mounted as a rotating body, the occurrence of vibration, etc., due to the decrease in rigidity of the rotating body generated at high speed rotation. Prevent it. In addition, by using the shaft 140 as a stationary body, it is possible to mount a plurality of platters 400 by increasing the rigidity, so that a large amount of information can be stored.

Second, the fluid hydrodynamic bearing motor of the present invention makes it possible to release the heat generated by separating the heat generating source by electromagnetic elements such as the core and the magnet and the heat generating source by the mechanical friction between the thrust plate and the sleeve. Reduce the deterioration of This prevents the lowering of the load bearing capacity and the additional friction phenomenon caused by the decrease of the viscosity of the oil.

Third, by adopting a cover block formed with an inclined groove that forms a fluid dynamic pressure at the upper end of the sleeve, it improves the internal pressure between the sleeve and the shaft to increase the bearing performance, and effectively prevent oil leakage due to the high internal pressure. Let's do it.

Claims (1)

In a hydrodynamic bearing motor in which a rotor is rotatably supported by a hydrodynamic bearing with respect to a stator, The stator includes a housing 100 fixed to the lower fixing body 220, a shaft 140 fixed to the central portion of the housing 100 and an upper end fixed to the upper fixing body 210, and the shaft. An annular thrust plate 171 is fixed to the upper end portion of the 140 and the core 130 is wound around the coil is fixed to the lower end of the central portion of the housing 100, The rotor is rotatably coupled to the shaft 140 to be rotatably supported by a hydrodynamic bearing, and coupled to an upper end of the sleeve 120 to thrust the sleeve 120. The cover block 170 for supporting the direction and the fluid groove is formed on the inner diameter surface to improve the pressure in the bearing, coupled to the outer periphery of the sleeve 120 and rotated together with the core 130 on the lower inner peripheral surface A shaft fixed type hydrodynamic bearing motor, characterized in that it comprises a hub (150) having a magnet (160) formed opposite to each other to form an electromagnetic circuit.