KR20130115512A

KR20130115512A - Spindle motor

Info

Publication number: KR20130115512A
Application number: KR1020120037865A
Authority: KR
Inventors: 박재운
Original assignee: 삼성전기주식회사
Priority date: 2012-04-12
Filing date: 2012-04-12
Publication date: 2013-10-22

Abstract

PURPOSE: A spindle motor is provided to prevent a coated adhesive from flowing inside a motor when a rotor magnet is bonded to the inside of a hub. CONSTITUTION: A spindle motor comprises a shaft (11), a sleeve (22), a hub (12), and a rotor magnet (13). The shaft becomes the center of rotation of a motor. The sleeve accommodates the shaft, and supports the shaft to be rotatable. The hub is combined with the upper end in the axial direction of the shaft, and comprises a rotor case (12a) and a bent unit (12b). The rotor magnet is combined with the inner side of the bent unit of the hub.

Description

[0001] SPINDLE MOTOR [0002]

The present invention relates to a spindle motor.

In general, a spindle motor belongs to a brushless DC motor (BLDC). In addition to a motor for a hard disk drive, a spindle motor includes a laser beam scanner motor for a laser printer, a motor for a floppy disk drive (FDD) And a motor for an optical disk drive such as a DVD (Digital Versatile Disk).

In order to minimize the occurrence of non-repeatable run out (NRRO), which is a vibration generated when noise and ball bearings are employed, in devices requiring high capacity and high driving force such as a hard disk drive in recent years, Spindle motors with hydrodynamic bearings are widely used. As described in the publication No. 20050094908 issued by the United States Patent and Trademark Office, a fluid dynamic pressure bearing basically forms a thin oil film between a rotating body and a stationary body to support the rotating body and the stationary body by pressure generated during rotation, So that the friction load is reduced. In the spindle motor using the hydrodynamic pressure bearing, the shaft of the motor for rotating the disk is kept at a dynamic pressure (a pressure at which the hydraulic fluid is returned to the center by the centrifugal force of the rotary shaft). Therefore, a spindle motor using the fluid dynamic pressure bearing is distinguished from a ball bearing spindle motor that supports a shaft with a bead.

When the hydrodynamic bearing is applied to a spindle motor, since the rotating body is supported by the fluid, the amount of noise generated by the motor is small, power consumption is low, and the impact resistance is excellent.

Conventional rotor magnets seated inside the spindle motor hub are typically joined by an adhesive. When the adhesive is applied to the inner side of the hub, the rotor magnet is slidingly coupled to the inner side of the hub, there is a problem that the adhesive applied to the inner side of the hub is pushed upward by the rotor magnet to leak the adhesive to the outside. In addition, the adhesive leaked in this way not only causes the internal pollution of the motor, but also has a problem that the outgas is generated by the high temperature generated when the motor is driven. In addition, when the adhesive used for bonding the rotor magnet is mixed with the working fluid inside to operate the hydrodynamic bearing, there is a problem that has a fatal effect of deteriorating the operating performance of the motor and the reliability of the driving.

The present invention has been made to solve the problems of the prior art as described above, one side of the present invention by securing the escape space of the adhesive on the upper end of the hub inner surface to which the rotor magnet is coupled, the rotor magnet to the hub inner surface It is to provide a spindle motor for preventing the motor inflow of the applied adhesive when adhesively bonded.

Spindle motor according to an embodiment of the present invention is a shaft that forms the center of rotation of the motor, the shaft for receiving the shaft, the shaft for supporting the shaft rotatably, the rotor coupled to the upper end in the shaft axial direction, extending in the outer direction A hub including a case and a bent portion bent downward in the axial direction from the outer end of the rotor case; And a rotor magnet coupled to the inner side of the hub bent portion, and a buffer groove may be formed on the inner side of the rotor case facing an end surface of the rotor magnet in an axial direction.

In one embodiment of the spindle motor, the buffer groove includes a first escape portion and a second escape portion, wherein the first escape portion is inwardly directed to the inner side of the rotor case in which an axial end surface of the rotor magnet abuts. The second escape portion may be a groove formed in an inward direction on an inner surface of the rotor case adjacent to the first escape portion and in which one end surface of the rotor magnet abuts.

In one embodiment of the spindle motor, the buffer groove may be formed as a semi-circular groove on the inner surface of the rotor case.

In one embodiment of the present invention, a spindle motor may further include a protruding jaw for supporting the rotor magnet between the first and second evacuation parts.

In one embodiment of the present invention, the second escape portion is formed in a semi-circular groove shape on the inner surface of the hub rotor case, a portion of the groove may be formed to open to the outer side of the rotor magnet axial end surface. have.

In one embodiment of the spindle motor, the buffer groove may be formed in an annular shape continuously along the inner circumference of the rotor case.

As an embodiment of the present invention, the spindle motor may further include a base coupled to surround the sleeve outer side to support the sleeve, and having a core wound with a coil wound at a position corresponding to the rotor magnet.

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, the adhesive applied to the inner surface of the hub to which the rotor magnet is coupled has an effect of preventing the outside of the coupling surface of the rotor magnet and the hub inner surface.

In addition, when the rotor magnet is slidingly coupled to the hub inner surface, it is possible to prevent the adhesive from being pushed out, thereby ensuring the reliability of the coupling of the rotor magnet and the hub inner surface.

In addition, the rotor magnet is slidingly coupled to the hub inner surface, thereby preventing the adhesive applied to the hub inner surface from leaking outside the adhesive surface of the hub inner surface, thereby preventing contamination in the motor.

In addition, by preventing the inflow of the adhesive used in the bonding process at the time of bonding the rotor magnet and the hub inner surface of the motor, it is possible to reduce the outgas generation inside the motor and improve the reliability of the motor operation.

In addition, by preventing the inflow of the adhesive used in the bonding process when the rotor magnet and the inner surface of the hub is bonded to the inside of the motor, by preventing the mixing with the working fluid used in the fluid dynamic bearing forming the shaft system of the motor, There is an effect that can improve the motor operating performance and the reliability of the driving.

1 is a cross-sectional view of the coupling of the hub and rotor magnet according to an embodiment of the present invention;
2 is a bottom view of the hub according to FIG. 1; And
2 is a cross-sectional view of the spindle motor according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The objectives, specific advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. Also, the terms "one side,"" first, ""first,"" second, "and the like are used to distinguish one element from another, no. In addition, the "axial direction" in the present invention is based on the extension direction of the shaft longitudinal direction forming the motor rotation center, as shown in Figure 3, the upper and lower portions in the extension direction of the shaft in the axial direction upper and lower Defined as DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the present invention, detailed description of related arts which may unnecessarily obscure the gist of the present invention will be omitted.

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

1 is a cross-sectional view of a coupling hub and rotor magnet according to an embodiment of the present invention, Figure 2 is a bottom view of the hub according to Figure 1, Figure 3 is a cross-sectional view of the spindle motor according to an embodiment of the present invention.

Spindle motor according to an embodiment of the present invention, the shaft 11 forming the center of rotation of the motor, the shaft 11 receives the shaft, the shaft 11 supports the rotatable, the shaft 11 A hub 12 coupled to the upper end in the axial direction and including a rotor case 12a extending in an outward direction and a bent portion 12b bent downward in the axial direction from an outer end of the rotor case 12a; And a rotor magnet 13 coupled to the inner side surface 12c of the bent portion 12b of the hub 12, the rotor case facing the axial end surface 13a of the rotor magnet 13 ( 12a) At least one buffer groove 70 may be formed on the inner surface.

According to the present invention, when the rotor magnet 13 is bonded to the inner surface 12c of the hub 12 by the bonding process, the adhesive is generated as the rotor magnet 13 is slidably coupled to the inner surface 12c of the hub 12. This is to block the inflow into the motor. To this end, in the present invention, the buffer groove 70 is formed in the inner coupling surface of the rotor case 12a of the hub 12 coupled to the rotor magnet 13 axial end surface 13a. As described below, the buffer groove 70 may be formed of at least one, and the present invention will be described with reference to an example formed of the first and second escape parts 71 and 72. .

The shaft 11 constitutes a central axis through which the spindle motor is rotationally driven, and is generally formed in a cylindrical shape. The thrust plate 41 is inserted into the upper end of the shaft 11 perpendicularly to the axial direction, but the thrust plate 41 can be inserted into the shaft 11 in the lower end as well as the upper end thereof so as to be perpendicular to the axial direction Of course. It is obvious to a person skilled in the art that the thrust plate 41 can be laser-welded to fix the shaft 11, but it can be press-fitted by applying a predetermined pressure to the thrust plate 41. In order to form the thrust dynamic pressure bearing part 40 by the hydrodynamic bearing, it is of course possible to generate dynamic pressure between the sleeve 22 or one surface of the facing hub 12 without a separate thrust plate 41.

The sleeve 22 is for rotatably supporting the shaft 11, and as shown in FIG. 3, the shaft 11 may support the shaft such that the upper end of the shaft 11 protrudes upward in the axial direction, and the shaft in a hollow cylinder shape. (11) can be accommodated by inserting into the hollow. The sleeve 22 may be formed by forging copper (Cu) or aluminum (Al), or by sintering a Cu—Fe alloy powder or a SUS powder. Between the outer circumferential surface of the sleeve 22 and the inner circumferential surface of the shaft 11 facing each other, a radial dynamic pressure bearing part 50 may be formed by fluid dynamic pressure. A radial dynamic pressure generating groove (not shown) is formed on the inner circumferential surface 22a of the sleeve 22 facing the outer circumferential surface 11a of the shaft 11 to form the radial hydrodynamic bearing portion 50, and the sleeve 22 is formed. The working fluid (for example, oil or the like may be used) is stored between the inner circumferential surface 22a and the outer circumferential surface 11a of the shaft 11. The radial dynamic pressure generating groove maintains a non-contact state between the shaft 11 and the sleeve 22 by generating fluid dynamic pressure using a working fluid stored between the sleeve 22 and the shaft 11 when the shaft 11 rotates. You can. The radial dynamic pressure generating groove may also be formed on the outer circumferential surface 11a of the shaft 11 forming the radial dynamic pressure bearing portion 50 by fluid dynamic pressure.

The hub 12 is coupled to the shaft 11 at the upper end of the shaft, and includes a rotor case 12a extending outwardly and a bent portion 12b bent downward in the axial direction at the outer end of the rotor case 12a. It can be formed to. The hub 12 is for mounting and rotating an optical disk or a magnetic disk, which is not shown. The hub 12 is coupled to the top of the shaft 11 so that the shaft 11 is integrally coupled to the center and corresponds to the axial upper surface of the sleeve 22. do. The rotor magnet 13 is attached to the inner surface 12c of the bent portion 12b of the hub 12 so as to face the core 23 of the base 21 to be described later in the radial direction. In particular, in the present invention, when the rotor magnet 13 is coupled to the inner surface 12c of the bent portion 12b of the hub 12, at least one buffer groove ( 70 may be further formed. The buffer groove 70 may be formed on the inner surface of the rotor case 12a and may be formed on the surface facing the one end surface 13a in the axial direction of the rotor magnet 13.

The core 23 generates magnetic flux as a magnetic field is formed when current flows. The rotor magnet 13 facing the magnet is repeatedly magnetized in the N pole and the S pole in the circumferential direction to form an electrode corresponding to the variable electrode generated in the core 23. The core 23 and the rotor magnet 13 are generated by the repulsive force due to the electromagnetic force due to the linkage of the magnetic flux, thereby rotating the hub 12 and the shaft 11 coupled thereto.

At least one buffer groove 70 may be formed on a mating surface corresponding to one end surface 13a of the rotor magnet 13 of the rotor case 12a in the at least one continuous or intermittently intermittently or intermittently. In particular, this embodiment describes an embodiment in which the buffer groove 70 is formed of the first escape portion 71 and the second escape portion 72, which is intended to help the understanding of the invention, the scope of the present invention It is not intended to limit

The first evacuation portion 71 may be formed in a groove shape formed inwardly on an inner surface of the rotor case 12a where the one end surface 13a of the rotor magnet 13 abuts. As shown in FIG. 1, the inner coupling surface of the rotor case 12a facing the one end surface 13a of the rotor magnet 13 may be formed. The first escape portion 71 may be formed in a semi-circular groove shape, but the present invention is not limited to such a shape, and may be formed in various shapes to form a space separated from the one end surface 13a of the rotor magnet 13. It will be apparent to those skilled in the art that the first skin 71 can be formed.

The second escape portion 72 may be formed adjacent to the first escape portion 71. The rotor magnet 13 may be formed on the inner surface of the rotor case 12a facing the one end surface 13a in the axial direction, which is the same as that of the first evacuation portion 71. The second escape portion 72 is formed adjacent to the first escape portion 71 and may be formed to be spaced apart from the first escape portion 71 in the radial direction inside the hub 12. As shown in FIG. 1, the second escape portion 72 may be formed in a semi-circular groove shape, and may be opened in the center direction of the hub 12 in the rotor magnet 13 axial end surface 13a. It may be a groove shape formed. A protruding jaw 73 may be further formed between the first and second evacuation parts 71 and 72 to support the rotor magnets 13 by being seated on one end surface 13a of the rotor magnets 13. . The protruding jaw 73 can support the load by the disk seated on the outside of the hub 12.

Although not shown, the buffer groove 70 of the present invention may be formed in two or more on the inner surface of the rotor case 12a of the hub 12 corresponding to the rotor magnet 13 axial end surface 13a. Appropriate design changes can be made by the shape and number of grooves to be formed. However, in order for the rotor magnet 13 axial end surface 13a to be coupled and supported, an appropriate design change may be possible according to the shape or size of the rotor magnet 13.

The buffer groove 70 may be formed in an annular shape along the circumference of the inner surface of the rotor case 12a. As shown in FIG. 2, the buffer groove 70 may be formed continuously in a circular shape on the inner circumferential surface of the hub 12.

In addition, the spindle motor according to an embodiment of the present invention is coupled to surround the outer surface of the sleeve 22 to support the sleeve 22, the coil 23a at a position corresponding to the rotor magnet 13 It may further include a base 21 on which the wound core 23 is mounted.

The base 21 is coupled so that one surface of the base 21 surrounds the outer circumferential surface of the sleeve 22 so that the sleeve 22 including the shaft 11 is coupled to the inside thereof. On the other side opposite to one surface of the base 21, the core 23 wound around the winding coil 23a is radially connected to the rotor magnet 13 mounted on the inner surface 12c of the bent portion 12b of the hub 12. Combined to correspond. The base 21 serves to support the overall structure at the bottom of the spindle motor, and the manufacturing method may be manufactured by a press working or die-casting method. Press working may be performed with a metal of various materials, such as aluminum and steel, and in particular, it is preferable to form a metal material having rigidity. A conductive adhesive (not shown) may be connected to the bottom surface at which the base 21 and the sleeve 22 are bonded to allow the overcharge generated in the shaft system to be conducted to the outside. Such a conductive adhesive can improve the reliability of the motor operation by allowing the overcharge generated during operation of the motor to conduct with the base 21 to flow out.

The core 23 is generally formed by stacking a plurality of thin metal plates, and is fixedly disposed on an upper portion of the base 21 on which the flexible printed circuit board 60 is provided. A plurality of through holes 21a through which the coils 23a wound around the core 23 are drawn out are formed on the bottom surface of the base 21, respectively, and the coils 23a exposed through the through holes 21a. The silver may be soldered to the flexible printed circuit board 60 to supply external power. An insulating sheet 21b may be formed at an inlet of the through hole 21a to insulate between the base 23 and the coil 23a passing through the through hole 21a of the base 21.

The configuration and operation relationship of the spindle motor according to an embodiment of the present invention will be briefly described with reference to FIG. 3 as follows.

The stator 20 is composed of a base 21, a sleeve 22, a core 22, and a core 24. The stator 20 includes a base 21, a sleeve 22, (23) and a pulling plate (24). The core 23 and the rotor magnet 13 are attached to the outer side of the base 21 and the inner side of the hub 12, respectively, where the core 23 forms a magnetic field when current flows, do. The rotor magnet 13 facing the core 23 is repeatedly magnetized with the N pole and the S pole to form an electrode corresponding to the variable electrode generated in the core 23. The core 23 and the rotor magnet 13 generate a repulsive force due to the electromagnetic force due to the linkage between the magnetic fluxes and thus the hub 12 and the shaft 11 coupled thereto rotate to drive the spindle motor of the present invention . Further, a pulling plate 24 is formed on the base 21 so as to correspond to the rotor magnet 13 in the axial direction in order to prevent floating of the motor when the motor is driven. The pulling plate 24 makes the rotary magnet 13 act gravitationally to enable stable rotation driving.

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 will be apparent that modifications and improvements can be made by those skilled in the art.

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.

10: rotor 11: shaft
11a: outer circumference of the shaft 12: hub
12a: rotor case 12b: bend
12c: inner side 13: rotor magnet
13a: rotor magnet end face 20: stator
21: Base 21a: Through Hole
21b: insulating sheet 22: sleeve
22a: inner sleeve surface 23: core
23a: coil 24: pulling plate
30: cover member 40: thrust dynamic pressure bearing part
41: thrust plate 50: radial dynamic bearing
60: flexible printed circuit board 70: buffer groove
71: first escape part 72: second escape part
73: protrusion

Claims

A shaft forming a rotation center of the motor;
A sleeve for receiving the shaft, the sleeve supporting the shaft rotatably;
A hub coupled to the shaft axial upper end, the hub including a rotor case extending outwardly and a bent portion bent downward in the axial direction from the outer end of the rotor case; And
Rotor magnet coupled to the inner side of the hub bent portion,
A spindle motor having a buffer groove formed in an inner surface of the rotor case facing an end surface in the axial direction of the rotor magnet.

The method according to claim 1,
The buffer groove includes a first escape portion and a second escape portion,
The first escape portion is a groove formed in the inward direction on the inner surface of the rotor case which the one end surface in the axial direction of the rotor magnet abuts,
And the second escape portion is a groove formed in an inward direction on an inner surface of the rotor case adjacent to the first escape portion and in which one end surface of the rotor magnet abuts.

The method according to claim 1,
The buffer motor is a spindle motor, characterized in that the groove of the semi-circular shape on the inner surface of the rotor case.

The method according to claim 2,
And a projection jaw for supporting the rotor magnet is further formed between the first and second sheaths.

The method according to claim 2,
The second escape portion is formed in a semi-circular groove shape on the inner surface of the hub rotor case, a portion of the groove is formed to open to the outer side of the rotor magnet axial end surface.

The method according to claim 1,
The shock absorbing groove is a spindle motor, characterized in that formed in an annular shape continuously along the inner circumference of the rotor case.

The method according to claim 1,
And a base coupled to surround the sleeve outer side to support the sleeve and having a core wound with a coil wound at a position corresponding to the rotor magnet.