KR20150088341A

KR20150088341A - Spindle Motor

Info

Publication number: KR20150088341A
Application number: KR1020110146258A
Authority: KR
Inventors: 김혁주; 김범초; 이타경
Original assignee: 삼성전기주식회사
Priority date: 2011-12-29
Filing date: 2011-12-29
Publication date: 2015-08-03

Abstract

A spindle motor according to one embodiment of the present invention includes: a shaft which forms the rotation center of a rotor; a sleeve which receives the shaft and rotationally supports the shaft; and a thrust plate which is combined to the shaft and generates the dynamic pressure of a shaft direction. The thrust plate is inclined from the rotation center to the upper side of the shaft direction of an outer radial direction. According to the present invention, the dynamic pressure of the shaft direction is improved by increasing the dynamic pressure generation groove processing area of a thrust dynamic bearing part of a fluid dynamic bearing.

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. The fluid dynamic pressure bearing basically forms a thin oil film between the rotating body and the fixed body and supports the rotating body and the fixed body by the pressure generated during rotation, so that the friction load is reduced because the rotating body and the fixed body do not contact each other. Therefore, the spindle motor to which the hydrodynamic pressure bearing is applied is to maintain the shaft of the motor for rotating the disk by dynamic pressure (a pressure at which the hydraulic pressure is returned to the center by the centrifugal force of the rotary shaft) of the lubricating oil And is distinguished from a ball bearing spindle motor that is supported by a shaft ball 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.

However, recently, as the use of a slim type motor having a narrow shaft space has been increased, there has been a problem that the design space of the dynamic pressure portion due to the thrust plate of the existing motor becomes narrow. In addition, as the design space for fluid dynamic pressure bearings becomes smaller, the dynamic pressure due to the fluid dynamic pressure bearing is reduced, thereby lowering the reliability of motor driving and affecting motor operation performance.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems of the conventional art as described above, and it is an object of the present invention to provide a thrust plate which is inclined upwardly in the axial direction to widen the machining area of thrust dynamic pressure generating grooves, And to provide an improved spindle motor.

According to an aspect of the present invention, there is provided a spindle motor including: a shaft that forms a rotation center of a rotor; a sleeve that receives the shaft and rotatably supports the shaft; And a thrust plate coupled to the shaft and generating an axial dynamic pressure, wherein the thrust plate is formed to be inclined upward from the rotation center in an outer radial direction axial direction.

In this case, a dynamic pressure generating groove is formed on a side surface in the axial direction of the thrust plate.

Further, the thrust plate is inclined to an upper side in the axial direction within a range of 10 to 30 degrees.

Further, the thrust plate is inclined upwardly in the range of 15 to 25 degrees from the upper side in the axial direction.

Further, a dynamic pressure generating groove is formed on a corresponding surface of the sleeve, which is inclined at a corresponding inclination, facing the axially upper side surface of the thrust plate.

Further, the thrust plate is integrally formed with the shaft.

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, there is an effect that the dynamic pressure generating force in the axial direction is improved by increasing the dynamic pressure generating groove machining area of the thrust dynamic pressure bearing portion by fluid dynamic pressure.

Further, there is the effect that the stability of the drive around the rotational axis can be ensured as the dynamic pressure is increased by increasing the machining area of the dynamic pressure generating groove formed in the thrust dynamic pressure bearing portion.

Further, by enlarging the machining area of the dynamic pressure generating groove formed in the thrust dynamic pressure bearing portion, it is possible to omit the member of the pulling plate by increasing the reverse pulling force or to prevent the floating of the rotor more effectively with the pulling plate There is an effect.

Further, the working area of the dynamic pressure generating groove formed in the thrust dynamic pressure bearing portion is increased, and the axial stiffness is improved as the dynamic pressure is increased.

Further, the thrust plate constituting the thrust dynamic pressure bearing portion is inclined upwardly in the axial direction to increase the dynamic pressure generating groove machining area, thereby securing an improved dynamic pressure than in the prior art, thereby improving the operating performance of the motor and securing reliability of the drive have.

Further, the thrust plate constituting the thrust dynamic pressure bearing portion is inclined upward in the axial direction to increase the dynamic pressure generating groove machining area, thereby enhancing the axial supporting force and enhancing the stability of the axial support.

1 is a sectional view of a spindle motor according to an embodiment of the present invention;
2 is a partial sectional view including the thrust hydrostatic bearing portion of Fig. 1; And
3 is an enlarged cross-sectional view of a portion A in Fig.

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. The term " axial direction " used in the present invention means a longitudinal direction in which a shaft constituting the rotation axis is formed, and the axial direction "upper" and "lower" refer to the upper and lower portions in the longitudinal direction of the shaft do. 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, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of a spindle motor according to an embodiment of the present invention, FIG. 2 is a partial cross-sectional view including a thrust hydrostatic bearing of FIG. 1, and FIG. 3 is an enlarged cross-

A spindle motor according to an embodiment of the present invention includes a shaft 11 constituting a rotation center of a rotor 10, a sleeve 22 receiving the shaft 11 and supporting the shaft 11 rotatably; And a thrust plate (40) coupled to the shaft (11) and generating an axial dynamic pressure, wherein the thrust plate (40) is formed to be inclined upward in the radial direction axially outward from the center of rotation do.

The shaft 11 constitutes a central axis through which the spindle motor is rotationally driven, and is generally formed in a cylindrical shape. A thrust plate 40 for forming a thrust dynamic pressure bearing portion 41 by fluid dynamic pressure can be inserted into the side portion of the shaft 11. Needless to say, the thrust plate 40 can be inserted into the lower end of the shaft 11 as well as the upper side of the shaft 11. It is obvious to those skilled in the art that the thrust plate 40 can be laser welded to fix the shaft 11 to the shaft 11, but it can be press-fitted to the thrust plate 40 with a predetermined pressure. Further, the thrust plate 40 may be formed integrally with the shaft 11. The thrust plate 40 may be provided with a dynamic pressure generating groove 40a in order to form the hydrodynamic pressure thrust hydrodynamic bearing portion 41. In particular, the present invention is characterized in that the thrust plate 40 is radially And is inclined toward the upper side in the axial direction. By forming the thrust plate 40 obliquely, there is an advantage that the machining area of the dynamic pressure generating groove 40a in the unit space can be further widened. Details will be described later.

The sleeve 22 accommodates the shaft 11 and has a hollow cylindrical shape for rotatably supporting the outer circumferential surface 11a of the coupled shaft 11 and the inner circumferential surface 22a of the sleeve 22 A radial dynamic pressure bearing portion 50 by a working fluid (including oil, for example) may be formed. A dynamic pressure generating groove (not shown) for generating a dynamic pressure of the radial dynamic pressure bearing portion 50 is formed on the outer peripheral surface 11a of the shaft 11 forming the radial dynamic pressure bearing portion 50 or formed on the outer peripheral surface 11a of the sleeve 11, The inner circumferential surface 22a. Particularly, by forming the thrust plate 40 obliquely and machining the dynamic pressure generating groove on the corresponding surface 22b of the sleeve 22 corresponding to the side surface 40b of the thrust plate 40, It is possible to improve the dynamic pressure of the fluid. Details will be described later.

The thrust plate 40 is engaged on the outer circumferential surface of the shaft 11 so as to be inclined in the axial direction. The thrust plate 40 generates fluid dynamic pressure by moving the shaft 11 toward the center of the dynamic pressure generating groove 40a by the pressure gradient of the working fluid (including, for example, lubricating oil such as oil) by rotating the shaft 11. [ Particularly, the present invention is characterized in that the thrust plate 40 is formed not to be formed perpendicular to the axial direction but to be inclined upward in the axial direction in the vertical direction. In the same unit space, the working area of the dynamic pressure generating groove 40a for generating the thrust dynamic pressure can be widened through the inclined thrust plate 40 structure.

Specifically, as shown in Figs. 2 and 3, the thrust plate 40 is coupled to the lower end of the shaft 11 and is formed to be inclined upward in the axial direction. The dynamic pressure generating groove 40a is formed on the side surface 40b of the thrust plate 40 to generate the dynamic pressure in the direction F in Fig. By generating a force in the direction F opposite to the sleeve 22 as the stator 20, the rotor 10 including the shaft 11 is subjected to a force pulled downward in the axial direction. Therefore, in the present invention, by eliminating the pulling plate 24 member and further improving the thrust dynamic pressure, the rotor 10 can be prevented from being damaged by using the separate pulling plate 24, It is possible to prevent injury. Further, through improved thrust dynamic pressure together with the pulling plate 24, more reliable motor drive reliability can be maintained. It is needless to say that the same effect can be realized by forming the dynamic pressure generating groove on the surface 22b corresponding to the sleeve 22 facing the thrust plate 40. [ The shaft 11 and the thrust plate 40 can be integrally formed. By generating the dynamic pressure in the F direction by the integrally formed thrust plate 40, the shaft 11 and the hub 12 coupled thereto are pulled down axially. Therefore, it is possible to prevent the abnormal rise of the rotor 10 that occurs during the motor drive. By further improving the thrust dynamic pressure of the thrust plate 40 inclined in the unit space, the stiffness in the axial direction can be increased. In addition, there is an advantage that the reliability of the thrust dynamic pressure due to the thinning of the motor can be maintained.

As shown in Fig. 3, the range of the angle [theta] at which the thrust plate 40 is inclined upward in the axial direction may be in the range of 10 [deg.] To 30 [deg.]. More preferably, the range of &thetas; may be in the range of 15 DEG to 25 DEG. the dynamic pressure generating groove 40a shows an increase rate of at least 15% to 35% in the range of 10 to 30 degrees and a dynamic pressure generating groove 40a of 25 to 37% at 15 to 25 degrees. Can be increased. For example, when the thrust plate 40 is inclined by 20 DEG, the machining area of the dynamic pressure generating groove 40a is increased by about 30% as compared with the conventional structure. By further improving the thrust dynamic pressure through the structure change of the thrust plate 40 of the present invention, as shown in Fig. 3, the rotor 10 including the shaft 11 by the force in the F direction generated by the thrust dynamic pressure, It is possible to prevent a rise in the axial direction upper direction. Further, as has been described, the rigidity in the axial direction can be further improved, and the reliability of the motor drive by the fluid dynamic pressure bearing can be further improved.

A spindle motor according to an embodiment of the present invention includes a base 21 coupled to an outer surface of the sleeve 22 to support the sleeve 22 and having a core 23 wound on the inner side thereof, And a hub 12 integrally coupled to the shaft 11 and having a rotor magnet 14 at a position corresponding to the core 23.

The base 21 is coupled to the outer surface of the sleeve 22 at one side so that the sleeve 22 including the shaft 11 is coupled inward. A core 23 wound with a winding coil is coupled to a position corresponding to the rotor magnet 13 formed on the hub 12 on the other side opposite to the one side of the base 21. The base 21 functions to support the entire structure in the lower part of the spindle motor, and the manufacturing method thereof can be manufactured by a press working or a die-casting method. The press-formed material may be made of a variety of metals such as aluminum and steel, but is preferably formed to have rigidity. The base 21 and the sleeve 22 can be assembled by applying an adhesive to the inner surface of the base 21 or the outer surface of the sleeve 22. [ A conductive adhesive agent (not shown) for connecting the base 21 and the sleeve 22 may be connected to the lower end surface to which the base 21 and the sleeve 22 are joined. By forming the conductive adhesive agent, the overcharge generated during the operation of the motor can be conducted to the base 21 and flow out, thereby improving the reliability of the operation of the motor.

The core 23 is generally formed by stacking a plurality of thin metal plates, and is fixedly disposed on a base 21 provided with a flexible printed circuit board (not shown). A plurality of through holes (not shown) corresponding to the coils drawn from the winding coils are formed on the lower end surface of the base 21, and the coils drawn through the through holes are soldered to be electrically connected to the flexible printed circuit board have. An insulating sheet (not shown) may be formed at the entrance of the base 21 formed with a through-hole for insulation between the coil and the base 21 through the through-hole.

The hub 12 is mounted on an upper surface of the shaft 11 so as to correspond to the upper end surface in the axial direction of the sleeve 22, . The rotor magnet 13 is formed so as to correspond to the core 23 of the base 21 in the radial direction. When a current flows through the core 23, a magnetic field is generated and a magnetic flux is generated. In the rotor magnet 13 facing the rotor magnet 13, the N pole and the S pole are repetitively magnetized 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 of the magnetic fluxes, and thus the hub 12 and the shaft 11 coupled thereto rotate.

The cover member 30 is engaged to cover the radial end surface of the sleeve 22 including the shaft 11, as shown in Fig. The cover member 30 can form a thrust dynamic pressure bearing portion 41 by forming a dynamic pressure generating groove (not shown) on the inner surface facing the lower end surface of the shaft 11. [ The cover member 30 is coupled to the end of the sleeve 22 and has a structure in which oil of the hydraulic oil can be stored therein.

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

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. In the rotor magnet 13 facing the rotor magnet 13, the N pole and the S pole are repetitively magnetized 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. Particularly, in the present invention, the pulling plate 24 for preventing the rotor 10 from floating is removed, the working area of the dynamic pressure generating groove 40a of the thrust plate 40 is increased, and the dynamic pressure in the F direction is used , It is possible to prevent the rotor 10 including the shaft 11 from being lifted (see Fig. 3). However, depending on the design, it may be applied together with the pulling plate 24 to maintain a more stable reliability of the motor drive.

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 peripheral surface of the shaft 12: hub
13: rotor magnet 20: stator
21: Base 22: Sleeve
22a: inner peripheral surface of sleeve 22b: corresponding surface
23: core 24: pulling plate
30: cover member 40: thrust plate
40a: Dynamic pressure generating groove 40b: Upper side
41: Thrust dynamic pressure bearing part 50: Radial dynamic pressure bearing part

Claims

A shaft forming the center of rotation of the rotor;
A sleeve receiving the shaft and supporting the shaft rotatably; And
And a thrust plate coupled to the shaft and generating an axial dynamic pressure,
Wherein the thrust plate is formed so as to be inclined upward in the radial direction axially outward from the rotation center.

The method according to claim 1,
And a dynamic pressure generating groove is formed on a side surface in the axial direction of the thrust plate.

The method according to claim 1,
Wherein the thrust plate is inclined upwardly in the range of 10 to 30 degrees from the upper side in the axial direction.

The method of claim 3,
Wherein the thrust plate is inclined upwardly in the axial direction by 15 to 25 degrees.

The method according to claim 1,
And a dynamic pressure generating groove is formed on a corresponding surface of the sleeve, which is inclined at a corresponding inclination, facing the axially upper side surface of the thrust plate.

The method according to claim 1,
Wherein the thrust plate is integrally formed with the shaft.