KR101412891B1 - Dynamic bearing assembly and spindle motor including thereof - Google Patents

Abstract

A hydrodynamic bearing according to an embodiment of the present invention comprises a rotation part having a hollow hole in which a shaft is inserted; a fixing part for supporting the shaft and the rotation part to be rotated by the dynamic pressure of lubricating fluid charged between the rotation part and the fixing part; an upper labyrinth sealing part coupled to the upper part of the shaft and arranged above the fixing part; and a lower labyrinth sealing part coupled to the lower part of the shaft and arranged under the fixing part. The present invention satisfies 1.1 × RRO <= RC <= 1.6 × RRO; 1.1 × ARO <= AC <= 1.6 × ARO (RC : The radial size of a gap between the rotation part and the fixing part, AC : The axial size of the gap between the rotation part and the fixing part, RRO : Radial assembly tolerance between the rotation part and the fixing part, and ARO : Axial assembly tolerance between the rotation part and the fixing part).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a fluid dynamic bearing assembly,

The present invention relates to a hydrodynamic bearing assembly and a motor including the same.

The vacuum cleaner includes a motor for vacuuming the interior of the vacuum cleaner. In a general vacuum cleaner motor, a ball bearing is used. However, when a ball bearing is used, noise or vibration generated at high speed rotation may adversely affect the performance of the motor, and resistance to external impact is low.

Further, when using a ball bearing, there is a disadvantage in that the performance of the motor may be deteriorated in a short time due to abrasion due to contact when the rotor rotates at a high speed.

An object of an embodiment of the present invention is to provide a fluid dynamic bearing assembly capable of increasing the service life of a motor, suppressing generation of noise or vibration during high-speed rotation, Motor.

The hydrodynamic bearing assembly according to an embodiment of the present invention includes: a rotating portion having a hollow into which a shaft is inserted; A fixing part for rotatably supporting the shaft and the rotary part by dynamic pressure of a lubricating fluid filled between the rotary part and the fixing part; An upper labyrinth sealing portion coupled to an upper portion of the shaft and disposed on the upper side of the fixing portion; And a lower labyrinth sealing portion coupled to a lower portion of the shaft and disposed below the fixing portion, wherein 1.1 x RRO? RC? 1.6 x RRO; 1.1 占 ARO? AC? 1.6 占 ARO.
(RC: size of gap in the radial direction between the rotating part and the fixing part, AC: size of gap in the axial direction between the rotating part and the fixing part, RRO: assembling tolerance in the radial direction between the rotating part and the fixing part, ARO : An assembling tolerance in the axial direction between the rotating portion and the fixing portion)

The rotating portion of the fluid dynamic pressure bearing assembly according to an exemplary embodiment of the present invention may include a vertical portion and a horizontal portion protruding outward in the radial direction from the center of the vertical portion.

The fixing portion of the fluid dynamic pressure bearing assembly according to an embodiment of the present invention may have a shape corresponding to the rotation portion.

A sealing portion may be formed such that oil is sealed between the vertical portion and the fixed portion of the fluid dynamic pressure bearing assembly according to an embodiment of the present invention.

The sealing portion of the hydrodynamic bearing assembly according to an embodiment of the present invention may include an upper sealing portion and a lower sealing portion.

The fixed portion of the fluid dynamic pressure bearing assembly according to an exemplary embodiment of the present invention and at least one of the facing surfaces of the upper labyrinth seal portion may be provided with a groove.

The fixed portion of the fluid dynamic pressure bearing assembly according to an exemplary embodiment of the present invention and at least one of the opposite surfaces of the lower labyrinth sealing portion may be provided with a groove.

A motor according to an embodiment of the present invention includes an upper housing; A lower housing coupled with the upper housing to provide an inner space; A shaft disposed in the inner space and having the hydrodynamic bearing assembly according to any one of claims 1 to 7 mounted on its upper portion and lower portion, respectively; A rotor core coupled to the shaft and rotated in association with the shaft; A stator coupled to the lower housing and disposed to have a micro gap with the rotor core; An impeller fixed on the shaft; And an impeller housing coupled to the upper housing.

According to the fluid dynamic pressure bearing assembly and the motor including the fluid dynamic pressure bearing assembly according to an embodiment of the present invention, it is possible to increase the life of the motor, suppress noise and vibration during high-speed rotation, have.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an assembled cross sectional view of a shaft and a hydrodynamic bearing according to an embodiment of the present invention; Fig.
2 is a cross-sectional view of the fluid dynamic pressure bearing assembly in the pumping direction of the lubricating fluid in accordance with one embodiment of the present invention.
3 is a cross-sectional view of a hydrodynamic bearing assembly according to an embodiment of the invention.
4 is a sectional view showing a state in which a vertical circulation hole and an oil reservoir are formed in a fluid dynamic pressure bearing assembly according to an embodiment of the present invention;
5 is a sectional view showing a state in which a vertical circulation hole, a horizontal circulation hole, and an oil reservoir are formed in a fluid dynamic pressure bearing assembly according to an embodiment of the present invention.
6 is a schematic cross-sectional view of a motor according to an embodiment of the present invention.
Figure 7 is an assembled cross-sectional view of a shaft, a hydrodynamic bearing assembly, and a rotor core in accordance with one embodiment of the present invention.
FIG. 8 is a cross-sectional view of a fluid dynamic pressure bearing assembly and an upper housing according to an embodiment of the present invention. FIG.
FIG. 9 is a cross-sectional view of an assembly of a fluid dynamic pressure bearing assembly and a lower housing according to an embodiment of the present invention. FIG.
10 is an engaging cross-sectional view of a hydrodynamic bearing assembly, a lower housing and a stator in accordance with an embodiment of the present invention.
FIG. 11 is an assembled sectional view of a hydrodynamic bearing assembly and a lower housing, a stator, and a rotor in accordance with an embodiment of the present invention. FIG.
12 is a cross-sectional view of a fluid dynamic pressure bearing assembly and a lower housing, an upper housing, and a stator in accordance with an embodiment of the present invention.
13 is a cross-sectional view of a fluid dynamic pressure bearing assembly and a lower housing, an upper housing, and a stator in accordance with an embodiment of the present invention.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventive concept. Other embodiments falling within the scope of the inventive concept may be easily suggested, but are also included within the scope of the present invention.

The same reference numerals are used to designate the same components in the same reference numerals in the drawings of the embodiments.

2 is a cross-sectional view of a fluid dynamic pressure bearing assembly according to an embodiment of the present invention, showing the direction of pumping of a lubricating fluid, and Fig. 3 Is a cross-sectional view of a hydrodynamic bearing assembly according to an embodiment of the present invention.

1 to 3, a fluid dynamic pressure bearing assembly 100 according to an embodiment of the present invention includes a shaft 110, a rotation unit 120, a fixing unit 130, an upper labyrinth sealing unit 140, And a lower labyrinth sealing portion 150. [

1, the axial direction refers to the vertical direction with respect to the shaft 110, and the radially outer or inner direction refers to the direction of the shaft 110 relative to the shaft 110, The direction of the center of the shaft 110 is referred to as an outer end of the shaft 120 or an outer end of the rotation unit 120.

The rotation unit 120 may include a hollow and the shaft 110 may be inserted and fixed to the hollow of the rotation unit 120. The shaft 110 may rotate in conjunction with the rotation unit 120 have.

The rotation part 120 may include a vertical part 122 and a horizontal part 124 protruding radially outward from the center of the vertical part 122.

The fixing portion 130 may support the rotation portion 120 in a rotatable manner and may have a shape corresponding to the rotation portion 120.

Specifically, the fixing portion 130 includes a circular plate portion 131 that faces the outer peripheral surface of the horizontal portion 124, and a circular plate portion 131 that extends radially inward from both ends of the circular plate portion 131, An extension portion 133 opposed to the upper surface and the lower surface and a tapered portion 135 extending axially in the extension portion 133 and opposed to the outer peripheral surface of the vertical portion 122.

The axial length of the disk 131 and the axial length of the taper 135 may be the same or the axial length of the taper 135 may be longer than the axial length of the disk 131 .

The fixing part 130 may be coupled to the rotation part 120 so as to have a minute gap with the rotation part 120, and a lubricating fluid may be filled in the minute gap.

The rotation of the shaft 110 and the rotation unit 120 is controlled by a fluid pressure generated by a dynamic pressure groove (not shown) formed on at least one of the inner diameter of the fixing unit 130 and the outer diameter of the rotation unit 120, Can be supported more smoothly.

A radial dynamic pressure groove (not shown) may be provided on an outer circumferential surface of the vertical portion 122 and the horizontal portion 124. The radial dynamic pressure grooves The rotation part 120 may be spaced apart from the fixing part 130 by a predetermined distance to smoothly rotate the rotation part 120 when the rotation part 120 rotates.

However, the radial dynamic pressure grooves (not shown) may be provided on the inner circumferential surface of the circular plate 131, and the number of the radial dynamic pressure grooves may be limited .

The radial dynamic pressure grooves (not shown) may be any one of a herringbone shape, a spiral shape, and a thread shape, and the shape is not limited as long as it generates a dynamic pressure.

A thrust dynamic pressure groove (not shown) may be provided on at least one of the upper surface and the lower surface of the horizontal portion 124 and the inner surface of the extended portion 133. The thrust dynamic pressure groove (not shown) (120) can rotate in conjunction with the shaft (110) while maintaining a certain lifting force.

The shape of the thrust dynamic pressure groove (not shown) may be a herringbone shape, a spiral shape, or a thread groove like the radial dynamic pressure groove (not shown), but the shape is not necessarily limited to this, It can be applied.

Referring to FIG. 2, the direction in which the lubricating fluid is pumped can be known by the pressure of the radial dynamic pressure groove (not shown) and the thrust dynamic pressure groove (not shown).

That is, the lubricating fluid can be pumped into the interface of the lubricating fluid by the radial dynamic pressure groove (not shown) and the thrust dynamic pressure groove (not shown), so that the lubricating fluid leaves the interface of the lubricating fluid It is possible to prevent leakage to the outside.

The radial dynamic pressure grooves (not shown) provided on the outer circumferential surface of the horizontal portion 124 or the inner circumferential surface of the circular plate portion 131 allow the lubricating fluid to flow between the horizontal portion 124 and the circular portion 131 And may be pumped to the center portion of the gap.

However, the spirit of the present invention is not limited by the pumping direction of the lubricating fluid, and the lubricating fluid is pumped to either the upper or lower portion of the gap between the horizontal portion 124 and the disk portion 131 It is also possible.

Sealing portions I1 and I2 may be formed between the vertical portion 122 and the tapered portion 135 to seal the lubricating fluid.

The sealing portions I1 and I2 include an upper sealing portion I1 formed on the upper side with respect to the horizontal portion 124 and a lower sealed portion I2 formed on the lower side with respect to the horizontal portion 124 can do.

That is, in the hydrodynamic bearing assembly 100 according to an embodiment of the present invention, the interface of the lubricating fluid may be formed on the upper side and the lower side with respect to the horizontal part 124, respectively.

The inner circumferential surface of the tapered portion 135 facing the vertical portion 122 may be tapered to seal the lubricating fluid.

Accordingly, the gap between the vertical portion 122 and the tapered portion 135 increases toward the upper side in the axial direction.

The upper rabbits sealing part 140 can be coupled to the upper side of the shaft 110 and the lower side railing sealing part 150 can be coupled to the lower side of the shaft 110, The sealing portions 140 and 150 may be disposed to form a minute gap with the outer circumferential surfaces of the tapered portion 135 and the extended portion 133.

At least one of the upper and lower labyrinth sealing parts 140 and 150 and the tapered part 135 and the fixing part 130 is provided with a groove to allow foreign matter to flow into the fluid dynamic pressure bearing assembly 100 It is possible to prevent the lubricating fluid from leaking.

That is, due to the groove, the gap between the upper and lower labyrinth sealing portions 140 and 150, the tapered portion 135, and the extended portion 133 is changed, thereby causing pressure drop and energy loss External foreign matter can be prevented from flowing into the fluid dynamic pressure bearing assembly 100, and the lubricating fluid can be prevented from leaking.

When the fluid dynamic pressure bearing is used in the motor for a vacuum cleaner as described above, noise and vibration can be suppressed at the time of high-speed rotation compared to the case of using a ball bearing, and the influence of abrasion due to contact is reduced. The lubricating fluid inside the fluid dynamic pressure bearing can act as a damping force to enhance the resistance against external impact.

FIG. 4 is a cross-sectional view showing a state in which a vertical circulation hole and an oil reservoir are formed in a fluid dynamic pressure bearing assembly according to an embodiment of the present invention, and FIG. 5 is a cross-sectional view of a hydrodynamic bearing assembly according to an embodiment of the present invention, Holes, a horizontal circulation hole, and an oil reservoir are formed.

4 and 5, the rotary units 120 'and 120''may include an oil reservoir 121, a vertical circulation hole 123, and a horizontal circulation hole 125.

An oil reservoir 121 is provided on the outer circumferential surface of the horizontal part 124 of the rotary part 120 'in the form of a groove so that the outer peripheral surface of the horizontal part 124 of the oil reservoir 121, The oil storage portion 121 can enlarge the storage space of the oil.

A vertical circulation hole 123 may be formed in the rotary part 120 'so that the upper surface of the horizontal part 124 and the lower surface of the horizontal part 124 communicate with each other. And a horizontal circulation hole 125 for communicating the oil reservoir 121 with the oil reservoir 121.

The vertical circulation holes 123 and the horizontal circulation holes 125 may maintain the equilibrium by dispersing the pressure of the lubricating fluid in the fluid dynamic pressure bearing assembly 100.

FIG. 6 is a schematic cross-sectional view of a motor according to an embodiment of the present invention, and FIG. 7 is an assembled cross-sectional view of a shaft, a fluid dynamic pressure bearing assembly, and a rotor core according to an embodiment of the present invention.

FIG. 8 is an assembled cross-sectional view of a fluid dynamic pressure bearing assembly and an upper housing according to an embodiment of the present invention, and FIG. 9 is an assembled cross-sectional view of a fluid dynamic pressure bearing assembly and a lower housing according to an embodiment of the present invention.

FIG. 10 is an assembled sectional view of a fluid dynamic pressure bearing assembly, a lower housing and a stator according to an embodiment of the present invention, FIG. 11 is a perspective view of a fluid dynamic pressure bearing assembly and a lower housing, FIG.

12 is a sectional view showing the fluid dynamic pressure bearing assembly, the lower housing, the upper housing, and the stator according to the embodiment of the present invention, FIG. 13 is a perspective view of the hydrodynamic bearing assembly according to the embodiment of the present invention, Sectional view of the housing and the stator.

6 to 13, a motor according to an embodiment of the present invention includes a fluid dynamic pressure bearing assembly 100, 100 ', an upper housing 400, a lower housing 500, a rotor 200, a stator 300 An impeller 600, and an impeller housing 700.

Here, the motor according to an embodiment of the present invention includes a fluid dynamic pressure bearing assembly 100 described with reference to FIGS. 1 to 5, which are respectively provided in an upper housing 400 and a lower housing 500, Assembly 100, 100 '.

Here, a fluid hydrodynamic bearing assembly 100 for coupling the upper housing 400 to the fluid dynamic pressure bearing assembly 100 and a fluid dynamic pressure bearing assembly for coupling the fluid dynamic bearing assembly 100 to the lower housing 500 are referred to as a second fluid dynamic pressure bearing assembly 100 ' .

The upper housing 400 may include a first fluid dynamic pressure bearing assembly 100 on an inner circumferential surface thereof and the lower housing 500 may include a second fluid dynamic pressure bearing assembly 100 'on an inner circumferential surface thereof.

In addition, the lower housing 500 may be coupled with the upper housing 400 to provide an internal space.

The stator 300 includes a stator core 310 having a plurality of salient poles, an insulator 320 formed of an insulating member and coupled to the stator core 310, and a stator coil 310 wound around the stator core 310 330).

The rotor 200 includes a rotor core 210 disposed to be rotatable with respect to the stator 300 and having a plurality of salient poles protruding in the radial direction of the rotor core 210 and a rotor core 210 coupled with the rotor core 210, And a shaft 110 that rotates in conjunction with the shaft 110.

That is, the rotor 200 may be arranged to have a minute clearance with the stator 300.

The shaft 110 may be disposed in the inner space provided by the upper housing 400 and the lower housing 500.

The shaft 110 may be inserted into the hollow of the rotation part 120 provided in the first fluid dynamic pressure bearing assembly 100 and the second fluid dynamic pressure bearing assembly 100 ' May be supported by the first fluid dynamic pressure bearing assembly 100 and the lower side of the shaft 110 may be supported by the second fluid dynamic pressure bearing assembly 100 '.

When the stator coil 330 is wound around the stator core 310, the rotor core 210 and the stator coil 330 are rotated together with the rotor 200, A rotational driving force is generated by an electromagnetic interaction with the wound stator core 310.

As a result, the rotor core 210 rotates so that the shaft 110 fixed to the rotor core 210 is rotated and the rotation unit 120 supporting the shaft 110 rotates And rotates in conjunction with the shaft 110.

An impeller 600 is coupled to the shaft 110 and the impeller 600 can rotate in conjunction with the shaft 110.

The impeller housing 700 may be coupled to the upper housing 400 so as to surround the impeller 600. The impeller housing 700 may include a through hole (not shown) .

Accordingly, external air can be sucked into the motor according to an embodiment of the present invention through the through hole (not shown) by the rotation of the impeller 600.

Here, since the upper housing 400 and the lower housing 500 are coupled to each other, assembly tolerances may occur at the time of coupling.

The size of the minute clearance between the fixing portion 130 and the rotation portion 120 may vary due to the assembly tolerance and may adversely affect the performance of the fluid dynamic pressure bearing. Therefore, the fixing portion 130 and the rotation portion 120 are required to be determined in consideration of manufacturing tolerances.

RC may mean the size of a small radial clearance between the rotating portion 120 of the fluid dynamic pressure bearing assembly and the fixing portion 130 and AC may be defined between the rotating portion 120 of the fluid dynamic pressure bearing assembly and the fixing portion 130 The size of the small clearance in the axial direction.

In addition, RRO can mean assembly tolerance in the radial direction, and ARO can mean assembly tolerance in the axial direction.

When the RC and the AC are smaller than the RRO and the ARO, the shaft 110 may not rotate after the assembling, so that the RC and the AC must be larger than the RRO and the ARO.

However, if the RC and the AC are larger than the RRO and the ARO, the size of the minute clearance between the rotating portion 120 of the fluid dynamic pressure bearing assembly and the fixing portion 130 becomes too large, I will not.

Therefore, in consideration of this, RC and AC need to have an appropriate size, so that RC and AC can satisfy the following conditional expressions 1 and 2, respectively.

[Conditional expression 1]

[Conditional expression 2]

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. .

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be apparent to those skilled in the art that changes or modifications may fall within the scope of the appended claims.

100: hydrodynamic bearing assembly 110: shaft
120: rotation part 130:
140: upper labyrinth sealing part 150: lower labyrinth sealing part
200: rotor 210: rotor core
300: stator 310: stator core
320: insulator 330: stator coil
400: upper housing 500: lower housing
600: impeller 700: impeller housing

Claims (8)

A rotating part having a hollow into which a shaft is inserted;
A fixing part for rotatably supporting the shaft and the rotary part by dynamic pressure of a lubricating fluid filled between the rotary part and the fixing part;
An upper labyrinth sealing portion coupled to an upper portion of the shaft and disposed on the upper side of the fixing portion; And
And a lower labyrinth sealing portion coupled to a lower portion of the shaft and disposed below the fixing portion,
1.1 占 RRO? RC? 1.6 占 RRO;
1.1 占 ARO? AC? 1.6 占 ARO.
(RC: size of gap in the radial direction between the rotating part and the fixing part, AC: size of gap in the axial direction between the rotating part and the fixing part, RRO: assembling tolerance in the radial direction between the rotating part and the fixing part, ARO : An assembling tolerance in the axial direction between the rotating portion and the fixing portion)
The method according to claim 1,
Wherein the rotating portion includes a vertical portion and a horizontal portion protruding radially outwardly from the center of the vertical portion.
3. The method of claim 2,
And the fixed portion has a shape corresponding to the rotation portion.
3. The method of claim 2,
And a sealing portion is formed between the vertical portion and the fixing portion to seal the oil.
5. The method of claim 4,
Wherein the sealing portion comprises an upper sealing portion and a lower sealing portion.
The method according to claim 1,
And a groove is provided in at least one of surfaces of the fixing portion and the upper labyrinth sealing portion facing each other.
The method according to claim 1,
And a groove is provided in at least one of the facing surfaces of the fixing portion and the lower labyrinth sealing portion.
An upper housing;
A lower housing coupled with the upper housing to provide an inner space;
A shaft disposed in the inner space and having the hydrodynamic bearing assembly according to any one of claims 1 to 7 mounted on its upper portion and lower portion, respectively;
A rotor core coupled to the shaft and rotated in association with the shaft;
A stator coupled to the lower housing and disposed to have a micro gap with the rotor core;
An impeller fixed on the shaft; And
And an impeller housing coupled to the upper housing.

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