KR20140081303A - Spindle motor - Google Patents

Abstract

The present invention relates to a spindle motor which forms a horizontal sealing structure interposed between the lower surface of a wing unit in a sleeve and the upper surface of a stopper using oil. The spindle motor includes a shaft; a sleeve including a wing unit protruding along the edge circumference of a cylinder-shaped upper surface; a rotor which has a cylinder unit extending from a hub to the lower side in the vertical direction; and a stopper which is fixed in the cylinder unit.

Description

[0001] The present invention relates to a spindle motor,

The present invention relates to a spindle motor.

BACKGROUND ART Spindle motors are widely applied as drive means for hard disk drives (HDD), optical disk drives (ODD), and other recording media requiring high-speed rotation.

That is, a spindle motor is a device that rotates a disk so as to read data recorded on the disk by means of a head. When a current is applied to the core, a magnetic field is generated. The magnetic field provides a magnetic force to the magnet provided in the rotor, and then the motor is driven to rotate by the operating principle of rotating the rotor through the magnetic force.

And a stopper for preventing the rotor from floating and separating from the stator when the rotor rotates at a high speed in a spindle motor. In the spindle motor according to the related art, the rotor case and the stopper are mutually fastened by a welding method such as a bonding method using an adhesive or a laser welding. The spindle motor fastened in this manner has the disadvantage that unnecessary foreign substances may remain in the motor during the coupling process.

To solve this problem, the spindle motor disclosed in Patent Document 1 proposes a structure for fastening the stopper to the rotor case without generating foreign matter. However, the spindle motor disclosed in Patent Document 1 is limited to merely improving the fastening manner between the stopper and the rotor case, and has a problem in that the gap between the rotor case, the sleeve, and the sleeve and the stopper affects the fluid dynamic pressure bearing to be provided in the vicinity thereof Will be.

Patent Document 1: Korean Patent Publication No. 10-2012-0000907

SUMMARY OF THE INVENTION It is an object of the present invention to provide a spindle motor in which a fluid dynamic pressure bearing is formed between a lower surface of a hub and an upper surface of a sleeve, and between a peripheral surface of a sleeve and a stopper,

In order to achieve this object, the present invention relates to a spindle motor having a horizontal sealing structure with oil interposed between a lower surface of a wing portion of a sleeve and an upper surface of a stopper, comprising: a shaft; A sleeve having a hollow cylindrical shape for rotatably supporting the shaft and having a wing protruding outwardly along a periphery of the top surface thereof; A base having a cylindrical support portion and a hollow portion formed at the center of the support portion for inserting and fixing the sleeve; A rotor fixed to an upper end of the shaft and extending in an outward direction, a cylindrical portion extending vertically downward from a lower surface of the hub, and a skirt portion extending vertically downward from an edge of the hub; And a stopper fixedly positioned inside the cylindrical portion at a predetermined distance from a lower surface of the hub of the rotor, wherein the wing portion of the sleeve is arranged between the hub and the stopper of the rotor.

In the present invention, the stopper has a cylindrical body portion and a stepped portion along the lower edge of the outer peripheral surface of the body portion, and is formed into a ring shape having an L-shaped cross section as a whole.

The body portion of the stopper further includes a chamfer portion along the upper edge of the outer circumference of the outer periphery of the stopper. When the inside of the body portion abuts against the inner periphery of the cylindrical portion, oil can be reserved through the chamfer portion.

In the present invention, the lower end of the stopper is spaced apart from the supporting portion of the base by a predetermined distance to minimize friction with the rotation of the rotor.

Preferably, the outer diameter of the wing portion is larger than the outer diameter of the body portion of the stopper, and the wing portion of the sleeve covers the upper surface of the stopper.

A bearing groove may be additionally formed on the upper surface of the stopper so that the stopper can support the sleeve, specifically the lower surface of the wing portion, through fluid dynamic pressure.

Optionally, the top surface of the sleeve may further form a thrust bearing groove to form a hydrodynamic bearing with the bottom surface of the hub.

Preferably, the ring-shaped cylindrical portion according to the present invention is designed such that the diameter of the lower portion and the upper portion of the cylindrical portion can be different through the bent portion, and the upper diameter of the cylindrical portion is formed larger than the lower diameter of the cylindrical portion about the bent portion. So that the wings of the sleeve arranged inside the cylindrical portion having such a structure are arranged on the valley portion.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

According to the present invention, a ring-shaped stopper having an L-shaped cross section can be mounted on the lower surface of the hub to provide a hydrodynamic bearing on the upper and outer surfaces of the sleeve.

The present invention can prevent oil from spreading by forming an oil interface on the upper surface of the stopper disposed close to the sleeve.

In addition, the present invention can provide a thrust bearing portion in a wide blade portion along the periphery of the sleeve top surface. This thrust bearing portion can reduce the friction generated by the mechanical contact between the lower surface of the hub of the rotor and the upper surface of the sleeve.

Therefore, the present invention not only assists in positioning between the constituent members but also reduces frictional torque, thereby reducing damage to parts, thereby maintaining the performance of the motor for a long time.

1 is a schematic cross-sectional view of a spindle motor according to an embodiment of the present invention.
Fig. 2 is an enlarged view of the arc portion of Fig. 1; Fig.
3 is a perspective view of the stopper to be applied to the present invention.

Now, a spindle motor according to the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages, features, and ways of accomplishing the same will become apparent from the following description of embodiments taken in conjunction with the accompanying drawings. In the specification, the same reference numerals denote the same or similar components throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

A spindle motor 100 according to the present invention includes a base 110, a sleeve 120, a shaft 130, a rotor 140, and a stator 150.

The base 110 is installed in a device such as a hard disk drive (not shown), and provides a space for accommodating the members constituting the motor therein. As shown in the figure, the base 110 is formed at its center with a cylindrical support portion 111, and the sleeve 120 is inserted and fixed into a hollow portion formed at the center of the support portion 111.

In addition, the base 110 is attached to a top surface of a pulling plate 112 made of a magnetic material, and the pulling plate 112 is preferably disposed at a portion adjacent to the magnet 145. A magnetic attractive force acts between the pulling plate 112 and the magnet 145.

The sleeve 120 may be assembled into the hollow portion to be provided with the support portion 111 of the base 110, as described above.

In addition, the sleeve 120 is generally cylindrical in shape so that the shaft 130 can be rotatably supported therein. The cylindrical sleeve 120 forms a wing 121 on its upper surface.

Specifically, the wing portion 121 protrudes radially outward along the periphery of the upper surface of the sleeve 120 as shown.

The sleeve 120 forms radial bearing grooves 123 that provide fluid hydrodynamic bearings on an inner circumferential surface spaced from the shaft 130 by a predetermined clearance while providing other hydrodynamic bearings on the upper surface abutting the hub Thereby forming thrust bearing grooves 122.

The spindle motor 100 according to the present invention having these bearing grooves 122 and 123 stably maintains the dynamic pressure between the sleeve 120 and the shaft 130 and between the sleeve 120 and the rotor 140, The driving characteristics of the spindle motor 100 according to the present invention can be improved.

The shaft 130 axially supports the hub 141 and is inserted into the sleeve 120 and is rotatably supported by the sleeve 120.

As described above, it is preferable that the shaft 130 is kept in a non-contact state at a predetermined distance to reduce the frictional force of contact with the inner circumferential surface of the sleeve 120. The gap between the shaft 130 and the sleeve 120 may be filled with a lubricant such as oil and may reduce friction with the sleeve 120 during rotation of the shaft 130 through oil.

The rotor 140 includes a circular hub 141, a skirt 142 for mounting the magnet 145, and a concentric circle having a diameter different from that of the skirt 142 on the lower surface of the hub 141. [ And has a cylindrical portion 143 of a structure.

The rotor 140 includes a shaft 130 on a vertical axis that coincides with the center of rotation of the hub 141. The shaft 140 is rotatably provided with respect to the stator 150 by forming an electric field for rotating the hub 141 .

Specifically, the hub 141 is fixed to the upper end of the shaft 130 at its center and extends outwardly as shown, preferably the hub 141 is supported by the flat upper surface of the sleeve 120. The cylindrical portion 143 extends vertically downward from the lower surface of the hub 141 in a hollow cylindrical shape and the skirt portion 142 extends vertically downward from the edge of the hub 141, And a ring-shaped magnet 145 is provided on the inner circumferential surface thereof.

The stator 150 is a fixed structure having a core 151 fixedly disposed on a base 110 and a coil 152 wound around the core 151 to generate an electric field.

In other words, the spindle motor 100 includes a ring-shaped magnet 145 disposed on the inner circumferential surface of the skirt portion 142 and disposed opposite to the core 151 at a predetermined interval. The magnet 145, which forms a magnetic field, Generates an electromagnetic force with the electric field formed by the coil 152. The rotor 140 of the spindle motor 100 of the present invention is rotated through this electromagnetic.

In particular, the spindle motor 100 according to the present invention employs a horizontal sealing structure, which can enhance the stability against shock and vibration of the spindle motor 100.

This horizontal sealing structure is formed by interposing oil in the gap between the sleeve 120 and the stopper 160, more specifically, between the lower surface of the wing portion 121 of the sleeve 120 and the upper surface of the stopper 160, The resulting fluid pressure can support the sleeve between the hub and the stopper. In particular, the horizontal sealing structure of the present invention is designed to prevent the oil, which acts as a fluid dynamic pressure bearing, from leaking out (for example, spreading, scattering, or evaporating oil) to the outside.

To this end, the stopper 160 is arranged on the cylindrical portion 143 of the rotor 140. Specifically, the stopper 160 is formed in a ring shape having an L-shaped cross section and disposed at the lowermost end of the cylindrical portion 143. In addition, the stopper 160 is spaced apart from the support portion 111 of the base 110 at a predetermined interval.

As shown, the stopper 160 has a cylindrical body portion 161 and a stepped portion 162 protruding radially from the lower edge of the outer peripheral surface of the body portion 161. Particularly, in order to ensure engagement between the stopper 160 and the cylindrical portion 143, the outer diameter of the body portion 161 is formed to be equal to or slightly smaller than the inner diameter of the cylindrical portion 143, . The stepped portion 162 ensures secure engagement of the stopper 160 and the rotor 140 into the space for seating the lowermost end of the cylindrical portion 143.

The chamfered portion 163 is formed by the inner circumferential surface of the cylindrical portion 143 extending vertically downwardly to a predetermined inner space . This inner space is used as the oil storage space of the oil.

The stopper 160 may form a bearing groove 164 on the upper surface of the stopper 160 so as to support the lower surface of the wing portion 121 of the sleeve 120 by means of fluid pressure. The outer diameter of the wing portion 121 is formed to be larger than the outer diameter of the body portion 161 of the stopper 160 so as to form the wing portion 121. In order to form the hydrodynamic bearing between the stopper 160 and the sleeve 120, So that the upper surface of the stopper 160 is entirely covered. Incidentally, the outer diameter of the wing portion 121 should be smaller than the inner diameter of the cylindrical portion 143.

Here, the bearing groove 164 is formed in various shapes such as a herringbone shape, a spiral shape, or a screw shape. The bearing groove is formed by rotating the stopper 160 with respect to the sleeve 120 via the oil filled in the horizontal sealing structure To generate radial dynamic pressure. 4, the bearing grooves are not illustrated to help understand the stopper 160 having the L-shaped sectional shape.

The bending portion 143b is formed in the cylindrical portion 143 extending vertically downward from the lower surface of the hub 141 so that the upper diameter of the cylindrical portion 143 and the lower diameter of the cylindrical portion 143 are Design differently. 2, the upper portion of the cylindrical portion 143 is formed to have a larger diameter than the lower portion, and the wing portion 121 of the sleeve 120 is received through the engagement protrusion formed by the difference between the upper diameter and the lower diameter, It is also possible to provide a space that can be used. Such a structure would provide a wide wing portion 121 to the sleeve 120 to reliably form a hydrodynamic bearing between the hubs.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the invention as defined by the appended claims. It is evident that it is possible to modify or modify it by the owner.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

100: spindle motor 110: base
120: sleeve 130: shaft
140: rotor 150: stator
160: Stopper

Claims (10)

A shaft;
A sleeve having a hollow cylindrical shape for rotatably supporting the shaft and having a wing protruding outwardly along an edge of the top surface thereof;
A base having a cylindrical support portion, a hollow portion formed at the center of the support portion for inserting and fixing the sleeve;
A rotor fixed to an upper end of the shaft and extending in an outward direction, a cylindrical portion extending vertically downward from a lower surface of the hub, and a skirt portion extending vertically downward from an edge of the hub; And
And a stopper fixedly positioned inside the cylindrical portion at a predetermined interval on a lower surface of the hub of the rotor,
And a wing portion of the sleeve is arranged between the hub of the rotor and the stopper.
The method according to claim 1,
Wherein the stopper is formed in a ring shape having an L-shaped cross section by forming a cylindrical body portion and a stepped portion along the lower edge of the outer peripheral surface of the body portion.
The method of claim 2,
Wherein the body portion of the stopper further comprises a chamfer portion along the upper edge of the outer periphery thereof.
The method according to claim 1,
And a horizontal sealing structure is formed through the oil interface between the lower surface of the wing portion and the upper surface of the stopper.
The method according to claim 1,
And the lower end of the stopper is spaced apart from the supporting portion of the base by a predetermined distance.
The method according to claim 1,
And the outer diameter of the wing portion is larger than the outer diameter of the body portion of the stopper.
The method of claim 2,
And the upper surface of the stopper further forms a bearing groove.
The method according to claim 1,
And the upper surface of the sleeve further forms a thrust bearing groove.
The method according to claim 1,
And the cylindrical portion has a bent portion.
The method of claim 9,
And an upper diameter of the cylindrical portion is larger than a lower diameter of the cylindrical portion about the bent portion.

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