KR20120043504A - Fluid dynamic bearing assembly - Google Patents

Fluid dynamic bearing assembly Download PDF

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Publication number
KR20120043504A
KR20120043504A KR1020100104839A KR20100104839A KR20120043504A KR 20120043504 A KR20120043504 A KR 20120043504A KR 1020100104839 A KR1020100104839 A KR 1020100104839A KR 20100104839 A KR20100104839 A KR 20100104839A KR 20120043504 A KR20120043504 A KR 20120043504A
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KR
South Korea
Prior art keywords
dynamic pressure
shaft
sleeve
pressure grooves
bearing assembly
Prior art date
Application number
KR1020100104839A
Other languages
Korean (ko)
Inventor
박상진
Original Assignee
삼성전기주식회사
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 삼성전기주식회사 filed Critical 삼성전기주식회사
Priority to KR1020100104839A priority Critical patent/KR20120043504A/en
Publication of KR20120043504A publication Critical patent/KR20120043504A/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/06—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings
    • F16C32/0629—Bearings not otherwise provided for with moving member supported by a fluid cushion formed, at least to a large extent, otherwise than by movement of the shaft, e.g. hydrostatic air-cushion bearings supported by a liquid cushion, e.g. oil cushion
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
    • G11B19/20—Driving; Starting; Stopping; Control thereof
    • G11B19/2009—Turntables, hubs and motors for disk drives; Mounting of motors in the drive
    • G11B19/2036—Motors characterized by fluid-dynamic bearings
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/08—Structural association with bearings

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Sliding-Contact Bearings (AREA)

Abstract

A shaft having a first dynamic pressure groove formed on an outer circumferential surface thereof, and a sleeve having the shaft inserted therein and having a second dynamic pressure groove formed on an inner circumferential surface facing the first dynamic pressure groove, wherein the first and second dynamic pressure grooves include: A hydrodynamic bearing assembly is disclosed that is formed to face in opposite directions to each other.

Description

Fluid dynamic bearing assembly

The present invention relates to a fluid dynamic bearing assembly, and more particularly, to a fluid dynamic bearing assembly having a dynamic groove.

Small spindle motors typically used in hard disk drives (HDDs) are equipped with a hydrodynamic bearing assembly and provide oil-like lubrication to bearing clearances formed between the shaft and sleeve of the hydrodynamic bearing assembly. The fluid is filled. The oil filled in the bearing gap is compressed to form a fluid dynamic pressure to rotatably support the shaft.

That is, in general, the fluid dynamic bearing assembly generates dynamic pressure through a spiral groove in the axial direction and a herringbone groove in the circumferential direction to improve the stability of the motor rotational drive.

However, the bearing gap formed between the shaft and the sleeve is so narrow that friction torque occurs during rotation of the shaft, thereby increasing the power consumption, and thus, the stability of the motor rotation drive is impaired.

It is an object of the present invention to provide a fluid dynamic bearing assembly capable of reducing frictional torque generated during rotation of a shaft.

The hydrodynamic bearing assembly according to the present invention includes a shaft in which a first dynamic pressure groove is formed on an outer circumferential surface thereof, and a sleeve in which the shaft is inserted and in which a second dynamic pressure groove is formed on an inner circumferential surface of the fluid dynamic bearing assembly. The first and second dynamic pressure grooves may be formed to face in opposite directions to each other.

The first and second dynamic pressure grooves may have a herringbone shape.

The first and second dynamic pressure grooves may include first and second upper dynamic pressure grooves and first and second lower dynamic pressure grooves having an axial length shorter than that of the first and second upper dynamic pressure grooves.

The first and second upper dynamic pressure grooves may be spaced apart from the first and second lower dynamic pressure grooves.

According to the present invention, the bearing clearance between the shaft and the sleeve can be increased through the first and second dynamic pressure grooves, thereby reducing the friction torque generated when the shaft rotates.

1 is a schematic cross-sectional view showing a motor having a fluid dynamic bearing assembly according to an embodiment of the present invention.
2 is an exploded perspective view illustrating a shaft and a sleeve provided in the hydrodynamic bearing assembly according to an embodiment of the present invention.
3 is an explanatory diagram for explaining first and second dynamic pressure grooves according to an exemplary embodiment of the present invention.

Hereinafter, with reference to the drawings will be described in detail a specific embodiment of the present invention. 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 which fall within the scope of the inventive concept may be easily suggested, but are also included within the scope of the present invention.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

1 is a schematic cross-sectional view showing a motor having a fluid dynamic bearing assembly according to an embodiment of the present invention, Figure 2 is an exploded perspective view showing a shaft and a sleeve provided in the fluid dynamic bearing assembly according to an embodiment of the present invention 3 is an explanatory diagram for explaining first and second dynamic pressure grooves according to an embodiment of the present invention.

1 and 2, the fluid dynamic bearing assembly 100 may include a shaft 110 and a sleeve 120.

On the other hand, the motor 10, in which the fluid dynamic bearing assembly 100 is installed, is a motor applied to a recording disk drive device for rotating a recording disk, and includes a rotor 20 and a stator 40.

The rotor 20 is provided with the cup-shaped rotor case 25 which equips the outer peripheral part with the annular magnet 26 corresponding to the stator core 42. As shown in FIG. The ring-shaped magnet 26 is a permanent magnet in which the N pole and the S pole are alternately magnetized in the circumferential direction to generate a magnetic force of a constant intensity.

In addition, the rotor case 25 may include a rotor hub 25a inserted into and fastened to the shaft 110 and a magnet coupling portion 25b for disposing an annular magnet 26 on an inner surface thereof.

The stator 40 means all fixed members except the rotating member, and includes a stator core 42 and a winding coil 44 surrounding the stator core 42.

On the other hand, the magnet 26 provided on the inner circumferential surface of the magnet coupling portion 25b is disposed to face the winding coil 44, the rotor 20 by the electromagnetic interaction of the magnet 26 and the winding coil 44 Will rotate. In other words, when the rotor case 25 rotates, the shaft 110 interlocking with the rotor case 25 rotates.

Here, when defining the term for the direction, as shown in Figure 1, the axial direction refers to the up and down direction relative to the shaft 110, the radial direction is the outer end of the rotor case 25 relative to the shaft 110 Direction or the center direction of the shaft 110 with respect to the outer end of the rotor case 25, the circumferential direction means the direction of rotation along the outer peripheral surface of the shaft (110).

The first dynamic pressure groove 112 is formed on the outer circumferential surface of the shaft 110. In addition, the shaft 110 is rotatably installed in the sleeve 120 and rotates in conjunction with the rotor case 25 when the rotor case 25 is rotated. That is, the shaft 110 is rotated in conjunction with the rotor case 25 is rotated by the electromagnetic interaction of the magnet 26 and the winding coil 44.

Meanwhile, the first dynamic pressure groove 112 may include a first upper dynamic pressure groove 112a and a first lower dynamic pressure groove 112b.

In addition, the first lower dynamic pressure groove 112b has a shorter axial length than the first upper dynamic pressure groove 112a, and thus, a space between the shaft 110 and the sleeve 120 when the shaft 110 rotates, That is, the lubricating fluid filled in the bearing gap may flow to the lower side.

In addition, the first upper dynamic pressure groove 112a and the first lower dynamic pressure groove 112b are spaced apart from each other by a predetermined interval.

In addition, the first dynamic pressure groove 112 may be formed to have a herringbone shape. Accordingly, the magnitude of the fluid dynamic pressure is maximized at the centers of the first upper dynamic pressure grooves 112a and the first lower dynamic pressure grooves 112b.

In the present embodiment, the case in which the first dynamic pressure groove 112 is formed as a herringbone shape is described as an example. However, the present invention is not limited thereto, and the first dynamic pressure groove 112 may employ any shape capable of forming fluid dynamic pressure. It will be possible. For example, the first dynamic groove 112 may be formed to have a spiral shape.

The shaft 110 is inserted into the sleeve 120, and a second dynamic pressure groove 122 is formed on an inner circumferential surface of the sleeve 120 to face the first dynamic pressure groove 112. The first and second dynamic pressure grooves 112 and 122 are formed to face in opposite directions to each other.

Meanwhile, the sleeve 120 may be formed by forging Cu or Al, or sintering Cu-Fe-based alloy powder or SUS-based powder, and may have the same outer diameter in the axial direction. Accordingly, the sleeve 120 may be manufactured in one mold.

In addition, the sleeve 120 may have a hollow cylindrical shape so that the shaft 110 can be inserted and mounted. That is, when the shaft 110 is inserted into the sleeve 120, a bearing gap is formed between the inner circumferential surface of the sleeve 120 and the outer circumferential surface of the shaft 110, and the bearing gap is filled with lubricating fluid.

Accordingly, the lubricating fluid filled during the rotation of the shaft 110 is compressed to form a fluid dynamic pressure so as to rotatably support the shaft 110.

On the other hand, the sleeve 120 may be provided with a circulation hole 124 for providing a movement path of the lubricating fluid in the axial direction so that the lubricating fluid filled in the bearing gap can be circulated. That is, the lubricating fluid filled between the inner circumferential surface of the sleeve 120 and the shaft 110 may be moved through the circulation hole 124 to flow counterclockwise.

Meanwhile, the second dynamic pressure groove 122 may also include a second upper dynamic pressure groove 122a and a second lower dynamic pressure groove 122b similarly to the first dynamic pressure groove 112.

In addition, the second lower dynamic pressure groove 122b has a shorter axial length than the second upper dynamic pressure groove 122a, and thus, a space between the shaft 110 and the sleeve 120 when the shaft 110 rotates, That is, the lubricating fluid filled in the bearing gap may flow to the lower side.

In addition, the second upper dynamic pressure groove 122a and the second lower dynamic pressure groove 122b are also spaced apart from each other so as to face the first upper dynamic pressure groove 112a and the second lower dynamic pressure groove 112b.

The second dynamic pressure groove 122 may be formed to face the opposite direction to the first dynamic pressure groove 112 disposed opposite to each other, but may have a herringbone shape.

In more detail, as shown in FIG. 2, the first upper and lower dynamic pressure grooves 112a and 112b are formed to face opposite directions of rotation of the shaft 110. The second upper and lower dynamic pressure grooves 122a and 122b are formed to face the same direction as the rotation direction of the shaft 110.

The centers of the first upper dynamic pressure grooves 112a and the second upper dynamic pressure grooves 122a are formed to face each other. In addition, the centers of the first lower dynamic pressure grooves 112b and the second lower dynamic pressure grooves 122b are also formed to face each other.

Accordingly, when the shaft 110 is rotated, the lubricating fluid is rotated in the rotational direction of the shaft 110 to the centers of the first and second upper dynamic pressure grooves 112a and 122a and the first and second lower dynamic pressure grooves 112b and 122b. To flow to form a fluid dynamic pressure.

Meanwhile, the sleeve 120 is installed in a fixed state, and the second upper and lower dynamic pressure grooves 122a and 122b are formed to face the same direction as the rotation direction of the lubricating fluid, so that the lubricating fluid is in the second upper and lower dynamic pressure grooves. It flows to the center side along 122b and 122b.

In addition, the shaft 110 is rotated, and the first upper and lower dynamic pressure grooves 112a and 112b are formed to face the direction opposite to the rotation direction of the lubricating fluid, so that the lubricating fluid is relatively first when the shaft 110 is rotated. The centers of the upper and lower dynamic grooves 112a and 112b are collected.

Accordingly, the magnitude of dynamic pressure generated through the first and second dynamic pressure grooves 112 and 122 is increased.

On the other hand, the bearing gap formed between the shaft 110 and the inner circumferential surface of the sleeve 120 may be wider than when the dynamic groove is formed on either the outer circumferential surface of the shaft 110 or the inner circumferential surface of the sleeve 120. .

That is, even if the shaft 110 is installed in the sleeve 120 so as to widen the bearing gap, the magnitude of dynamic pressure generated when the shaft 110 is rotated by the first and second dynamic pressure grooves 112 and 122 is increased, and thus, the shaft 110 is formed. Can be rotated more stably.

As a result, since the first and second dynamic pressure grooves 112 and 122 are formed in the shaft 110 and the sleeve 120, the shaft 110 may be installed in the sleeve 120 so as to widen the bearing gap, and thus the shaft ( The friction torque generated when the 110 is rotated can be reduced.

In addition, since the shaft 110 is installed in the sleeve 120 to widen the bearing gap, the shaft 110 may be more easily installed in the sleeve 120. That is, assembling of the shaft 110 may be improved.

In the present embodiment, the second dynamic groove 122 has a herringbone shape as an example, but the present invention is not limited thereto. The second dynamic groove 122 may correspond to the shape of the first dynamic groove 112. It may be formed to have a shape. For example, when the first dynamic pressure groove 112 is formed to have a spiral shape, the second dynamic pressure groove 122 may also be formed to have a spiral shape.

As described above, the magnitude of dynamic pressure generated when the shaft 110 is rotated through the first and second dynamic pressure grooves 112 and 122 which are formed to face in opposite directions to each other may be increased, and thus the shaft 110 and the sleeve 120 may be increased. The gap between the bearings formed between the two poles can be increased.

Accordingly, the friction torque generated when the shaft 110 rotates can be reduced, and in addition, the assemblability of the shaft 110 can be improved.

On the other hand, the hydrodynamic bearing assembly 100 according to an embodiment of the present invention shown in the drawings is partially exaggerated for the description of the present invention, showing the actual hydrodynamic bearing assembly 100 It is not a drawing.

10 motor 100 hydrodynamic bearing assembly
110: shaft 120: sleeve

Claims (4)

A shaft having a first dynamic pressure groove formed on an outer circumferential surface thereof;
A sleeve having the shaft inserted therein and having a second dynamic pressure groove disposed on an inner circumferential surface thereof so as to face the first dynamic pressure groove;
Including;
And the first and second dynamic pressure grooves are formed to face in opposite directions to each other. The method of claim 1,
And said first and second dynamic pressure grooves have a herringbone shape. The method of claim 1,
The first and second dynamic pressure grooves may include first and second upper dynamic pressure grooves and first and second lower dynamic pressure grooves having an axial length shorter than that of the first and second upper dynamic pressure grooves. assembly. The method of claim 3,
And the first and second upper dynamic pressure grooves are spaced apart from the first and second lower dynamic pressure grooves.
KR1020100104839A 2010-10-26 2010-10-26 Fluid dynamic bearing assembly KR20120043504A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020100104839A KR20120043504A (en) 2010-10-26 2010-10-26 Fluid dynamic bearing assembly

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Application Number Priority Date Filing Date Title
KR1020100104839A KR20120043504A (en) 2010-10-26 2010-10-26 Fluid dynamic bearing assembly

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KR20120043504A true KR20120043504A (en) 2012-05-04

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109404416A (en) * 2018-12-14 2019-03-01 中国船舶重工集团公司第七0七研究所 A kind of hydrodynamic pressure bearing and its manufacturing method
WO2020013950A1 (en) * 2018-07-10 2020-01-16 Stein Seal Company Circumferential seal with bifurcated flow along multi-axis stepped grooves
US10648507B2 (en) 2013-04-15 2020-05-12 Stein Seal Company Circumferential back-to-back seal assembly with bifurcated flow
US10711839B2 (en) 2013-04-15 2020-07-14 Stein Seal Company Circumferential seal with bifurcated flow along multi-axis stepped grooves
US10948014B2 (en) 2013-04-15 2021-03-16 Stein Seal Company Intershaft seal assembly with multi-axis stepped grooves
US11686346B2 (en) 2013-04-15 2023-06-27 Stein Seal Company Circumferential seal assembly with multi-axis stepped grooves

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10648507B2 (en) 2013-04-15 2020-05-12 Stein Seal Company Circumferential back-to-back seal assembly with bifurcated flow
US10711839B2 (en) 2013-04-15 2020-07-14 Stein Seal Company Circumferential seal with bifurcated flow along multi-axis stepped grooves
US10948014B2 (en) 2013-04-15 2021-03-16 Stein Seal Company Intershaft seal assembly with multi-axis stepped grooves
US11686346B2 (en) 2013-04-15 2023-06-27 Stein Seal Company Circumferential seal assembly with multi-axis stepped grooves
US11732753B2 (en) 2013-04-15 2023-08-22 Stein Seal Company Circumferential seal assembly with multi-axis stepped grooves
WO2020013950A1 (en) * 2018-07-10 2020-01-16 Stein Seal Company Circumferential seal with bifurcated flow along multi-axis stepped grooves
CN109404416A (en) * 2018-12-14 2019-03-01 中国船舶重工集团公司第七0七研究所 A kind of hydrodynamic pressure bearing and its manufacturing method

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