• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The pneumatic hydrodynamic bearing structure for supporting the rotating body according to the present invention is fixed to the upper end of the shaft for fixing the rotating body, the upper conical bearing member having a conical inclined surface for forming the pneumatic hydrodynamic bearing; A lower conical bearing member fixed to a lower end of the shaft and having a conical inclined surface for forming an pneumatic hydrodynamic bearing; And spaced apart from the structure consisting of the upper and lower conical bearing members and the shaft at a predetermined gap so as to enclose the structure in the radial direction of the shaft, and forming a pneumatic hydrodynamic bearing by the gap with the structure while rotating the body on the outer peripheral surface thereof. And a cylindrical bearing bush member for securing. According to the present invention, since the rotating body is supported by a non-contact type by pneumatic bearings rather than by a conventional ball bearing, vibration and noise when using the ball bearing can be prevented, and accordingly, high speed and high precision rotation can be achieved. The needs can be realized.
    公开号:KR19990034418A
    申请号:KR1019970056023
    申请日:1997-10-29
    公开日:1999-05-15
    发明作者:황태연
    申请人:이형도；삼성전기 주식회사；
    IPC主号:
    专利说明:

    Pneumatic Hydrodynamic Bearing Structure for Rotor Support
    BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic hydrodynamic bearing structure for supporting a rotating body employed in a spindle motor shaft of a hard disk drive, and the like, in particular, using magnetic repulsive force and pneumatic pressure for axial support, The present invention relates to a pneumatic hydrodynamic bearing structure for supporting a rotating body that enables non-contact supporting of the rotating body.
    The hard disk drive is one of the auxiliary storage devices of the computer, and contributes to the operation of the computer by reading and playing the information stored on the magnetic disk by the magnetic head or recording new information on the magnetic disk.
    Such a hard disk drive has recently advanced to high speed, high capacity, and low vibration, and various research and developments are being pushed to meet such demands. In particular, research has been actively conducted on a pneumatic hydrodynamic bearing structure that supports a rotating body in a non-contact manner for high speed and low vibration.
    1 is a plan view schematically showing a hard disk drive employing a conventional ball bearing structure.
    Referring to FIG. 1, a hard disk drive includes a base housing 11, a magnetic disk 12 for storing information, and a head for recording information on or reading information recorded on the magnetic disk 12. It consists of a voice coil motor 14 which provides a driving force for reciprocating the stack assembly 13 and the head stack assembly 13 in the radial direction of the magnetic disk 12.
    Here, the magnetic disk 12 is fixed to the hub 16 by the clamp 15, the head stack assembly 13 is installed so as to be able to pivot about the pivot (13p). The head stack assembly 13 includes an actuator 13a, a plate-like load beam 13b having an elastic force, which is extended to and coupled to the actuator 13a, and a load beam 13b. It is composed of a magnetic head 13h fixed to an end to read information recorded on the magnetic disk 12 or to record new information on the magnetic disk 12.
    In addition, a ferromagnetic iron piece 17 is provided at an end of the actuator 13a opposite to the magnetic head 13h, and the iron piece 17 is stopped on the turning movement trajectory of the iron piece 17 when the hard disk drive is stopped. A latch 18 for securing the head stack assembly 13 by attracting and attracting 17 is provided. Here, the latch 18 is composed of a permanent magnet 18m and a fixing member 18s for fixing the permanent magnet 18m.
    2 is a cross-sectional view taken along the line II-II of FIG. 1.
    2, a ball bearing 22 is press-fitted to the shaft 21 fixed to the base housing 11, the hub 16 is press-fitted to the outer ring 22e of the ball bearing 22, On the outer circumference of the hub 16, a plurality of magnetic disks 12 are provided in a stack spaced apart from each other by a predetermined interval. In addition, a permanent magnet 23 is provided on one side of the lower end of the hub 16, and a stator coil 24 is provided in the base housing 11 adjacent to the permanent magnet 23. Reference numeral 22b denotes a ball, 22i denotes an inner ring, and 25 denotes a spacer member that fixes the magnetic disk 12 at predetermined intervals.
    On the other hand, in the conventional hard disk drive having the above configuration, the ball 22b of the ball bearing 22 is the axial direction (S) and the radial direction of the rotating body (assembly of the hub 16 and the magnetic disk 12). (R) As shown in Fig. 3, the inner ring 22i and the outer ring 22e are in contact with each other so as to be supported at the same time as shown in Fig. 3. In order to achieve the inclination of the predetermined angle θ, the ball bearing 22 is assembled to the fixed shaft 21, and then a predetermined amount of preload is applied. In this case, when the ball bearing 22 is press-fitted and assembled, the inner ring 22i, the outer ring 22e and the ball 22b come into contact with each other, and the rotating body rotates in such a contact-supported state. In this way, when the rotating body is supported by the ball bearing 22, the inner ring 22i, the outer ring 22e and the ball 22b are easily deformed by mutual contact, and due to each processing error, etc. In this case, irregular vibration and noise are easy to occur, and especially, a non-repeatable run-out (NRRO) is large. The irregular rotation vibration amplitude is a major factor in determining the mechanical performance of a spindle motor for a high density storage device requiring ultra-precision vibration characteristics. As described above, in order to improve the vibration characteristics of the rotating body supported by the ball bearing, there is a method of processing the ball bearing with high precision, but the durability of the rotating system is a problem due to the generation of wear and frictional heat caused by contact support.
    SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a pneumatic hydrodynamic bearing structure for supporting a rotating body capable of minimizing an irregular rotation response amplitude and noise in the rotation of the rotating body.
    1 is a plan view schematically showing a hard disk drive employing a conventional ball bearing structure.
    FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1. FIG.
    Figure 3 is an assembled state of the ball, inner ring and outer ring of the conventional ball bearing structure.
    Figure 4 is an exploded perspective view showing a pneumatic hydrodynamic bearing structure for supporting the rotating body according to the present invention.
    Figure 5 is a longitudinal sectional view in the assembled state of the pneumatic hydrodynamic bearing structure for supporting the rotor according to the present invention.
    Figure 6 is an enlarged partial excerpt showing a magnetic thin film coated on the surface of the pneumatic hydrodynamic bearing in the rotating body supporting pneumatic bearing structure according to the present invention.
    7 is a cross-sectional view showing a case in which the outer circumferential surface of the shaft is formed as a curved surface of a sinusoidal waveform in the rotor supporting pneumatic hydrodynamic bearing structure according to the present invention.
    8 is a cross-sectional view showing a case in which the inner circumferential surface of the bearing bush member is formed as a sinusoidal waveform in the pneumatic hydrodynamic bearing structure for supporting the rotating body according to the present invention;
    9 is a view showing a bearing reaction force acting on the bearing structure during rotation of the rotor in the rotor supporting pneumatic hydrodynamic bearing structure according to the present invention.
    10 is a pressure distribution diagram of a bearing generated in a journal pneumatic bearing in a rotating body supporting pneumatic bearing structure according to the present invention.
    <Explanation of symbols for main parts of the drawings>
    11 ... base housing 12 ... magnetic disc
    13 ... head stack assembly 13a ... actuator
    13b ... loaded beam 13h ... magnetic head
    13p ... Pivot 14 ... Voice Coil Motor
    15 Clamp 16 Hub
    17.Iron 18.Latch
    18 m.Permanent magnet 18 s.
    21, 41 ... Shaft 22 ... Ball bearing
    23 permanent magnet 24 stator coils
    25 Spacer member 22 b Ball
    22i ... inner ring 22e ... outer ring
    42.Upper conical bearing member 43 ... Lower conical bearing member
    45 ... cylindrical bearing bush members 42m, 43m, 45m, 45m '... magnetic thin film
    In order to achieve the above object, a pneumatic hydrodynamic bearing structure for supporting a rotating body according to the present invention comprises: an upper conical bearing member fixed to an upper end of a shaft for fixing a rotating body and having a conical inclined surface for forming an pneumatic hydrodynamic bearing; A lower conical bearing member fixed to a lower end of the shaft and having a conical inclined surface for forming an pneumatic hydrodynamic bearing; And spaced apart from the structure consisting of the upper and lower conical bearing members and the shaft at a predetermined gap so as to enclose the structure in the radial direction of the shaft, and forming a pneumatic hydrodynamic bearing by the gap with the structure while rotating the body on the outer circumferential surface thereof. Its feature is that it includes a cylindrical bearing bush member for securing.
    Here, in particular, in order to prevent the phenomenon of contact between the shaft and the rotating body from the start of the rotating body to the rise and rise, and to further enhance the axial and radial bearing capacity by the pneumatic bearing, A magnetic thin film is coated on the conical inclined surface portion of the lower conical bearing member and the conical inclined surface portion of the bearing bush member facing the inclined surface portion, respectively. At this time, such a magnetic thin film is coated so that the magnetic poles facing each other have the same polarity.
    Further, in order to increase the radial bearing force of the rotating body, preferably, the wavy journal air bearing is formed between the outer circumferential surface of the shaft between the upper and lower conical bearing members fixed to the shaft and the inner circumferential surface of the bearing bush member facing it. waved journal air bearing, for which the outer circumferential surface of the shaft between the upper and lower conical bearing members fixed to the shaft or the inner circumferential surface of the bearing bush member facing it is formed as a curved surface of a sinusoidal waveform having a predetermined period and amplitude. do.
    According to the present invention, since the rotating body is supported by a non-contact type by pneumatic bearings rather than by a conventional ball bearing, vibration and noise when using the ball bearing can be prevented, and accordingly, high speed and high precision rotation can be achieved. The needs can be realized.
    Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
    4 and 5 show a pneumatic hydrodynamic bearing structure for supporting the rotor according to the present invention, Figure 4 is an exploded perspective view, Figure 5 is a longitudinal cross-sectional view in the assembled state.
    4 and 5, the pneumatic hydrodynamic bearing structure for supporting the rotor according to the present invention is fixed to the upper end of the shaft 41 for fixing the rotor, the upper portion having a conical inclined surface for forming the pneumatic hydraulic bearing A lower conical bearing member 43 and a lower conical bearing member 42 fixed to a lower end of the shaft 41 and having a conical inclined surface for forming a pneumatic bearing, and the upper and lower conical bearing members 42 and 43. Spaced apart from the structure 44 formed of the shaft 41 and the shaft 41 so as to surround the structure 44 in the radial direction of the shaft 41, and the pneumatic hydraulic bearing is formed by the gap with the structure 44. It is formed of a cylindrical bearing bush member 45 which forms a rotating body on the outer circumferential surface thereof.
    Here, in particular, the contact phenomenon between the shaft 41 and the rotating body from the time of stopping of the rotating body to the rising of the floating body is prevented, and the bearing force in the axial direction S and the radial direction R by the pneumatic hydraulic bearing is further increased. For the sake of improvement, the conical inclined surface portions of the upper and lower conical bearing members 42 and 43 and the conical inclined surface portions of the bearing bush member 45 facing the inclined surface portions are respectively shown in FIG. Magnetic thin films 42m, 43m, 45m (45m ') are coated. At this time, the magnetic thin films 42m, 43m, 45m, and 45m 'as well as the magnetic poles facing each other have the same polarity (for example, N-pole or S-pole). Coated to a thickness of 2 μm. This thickness t is a value based on 1/3, which is an appropriate ratio thereof, on the basis that the bearing clearance C which normally forms the pneumatic bearing is about 3 to 4 m.
    Further, in order to increase the radial bearing force of the rotating body, preferably the outer peripheral surface of the shaft between the upper and lower conical bearing members 42 and 43 fixed to the shaft 41 and the bearing bush member 45 facing it. A wavy wave journal air bearing is formed between the inner circumferential surfaces of the circumferential surface, and the shaft between the upper and lower conical bearing members 42, 43 fixed to the shaft 41 as shown in FIG. The outer circumferential surface of 41) is formed into a curved surface of a sinusoidal waveform having an N period and an amplitude of several microns. At this time, it is preferable that the inner circumferential surface of the bearing bush member 45 be processed as precisely as close to the true circle as possible.
    Alternatively, as shown in FIG. 8, the inner circumferential surface of the bearing bush member 45 facing the outer circumferential surface of the shaft 41 is similarly formed into a curved surface of a sinusoidal waveform having an N period and an amplitude of several microns. At this time, it is also preferable that the outer circumferential surface of the shaft 41 is processed precisely close to the roundness.
    Then, the operation of the rotor supporting pneumatic hydrodynamic bearing structure according to the present invention having the configuration as described above will be described.
    When the rotor rotates at a high speed in a state in which the rotor consisting of the assembly of the hub 16 (see Fig. 2) and the magnetic disk 12 is press-fitted to the outer circumferential surface of the bearing bush member 45, as shown in FIG. Similarly, in the gap between the conical inclined surface portions of the upper and lower conical bearing members 42 and 43 and the upper and lower conical inclined surface portions of the bearing bush member 45 facing each other, the pneumatic pressure due to the static eccentricity of the rotating body, that is, Bearing reaction forces F and F 'are respectively generated to act in a direction perpendicular to the bearing surface. At this time, the bearing reaction force (F) (F ') can be separated into reaction force (Fs) (Fs') of the axial component and reaction force (Fr) (Fr') of the radial component, respectively, such an axial direction The rotor is supported in the axial direction S and in the radial direction R by the reaction force Fs (Fs ') of the component and the reaction force Fr (Fr') of the radial component, respectively.
    In addition, in the clearance between the outer circumferential surface of the shaft 41 between the upper and lower conical bearing members 42 and 43 and the inner circumferential surface of the bearing bush member 45 facing the outer circumferential surface of the shaft 41 as described above. Alternatively, the inner circumferential surface of the bearing bush member 45 facing the outer circumferential surface is formed as a sinusoidal curved surface having an N period and an amplitude of several microns, whereby a journal air dynamic bearing is formed, whereby the journal bearing reaction force J is And act in a direction perpendicular to the axis 41. Thereby, the radial bearing force on the rotating body is further enhanced. FIG. 10 shows a calculation example of a radial dimensionless pressure distribution (pressure distribution divided by atmospheric pressure) generated in such a journal pneumatic bearing, wherein a circle represented by a dotted line having a radius of 1 is atmospheric pressure as a reference pressure. Indicates. A value greater than atmospheric pressure in the radial direction represents a positive pressure and a value less than a negative pressure. The position showing the maximum pressure value represents a radial static eccentric position at the time of rotation of the bearing bush member 45, and the bearing reaction force of the air dynamic bearing can be calculated by integrating the pressure distribution in the circumferential direction. At this time, the bearing reaction force may be referred to as a bearing reaction force for radial support of the rotor as described in FIG. 9 near the static eccentric position of the rotor.
    On the other hand, the reaction force by the pneumatic hydrodynamic bearing as described above is generated only when the rotating body is rotating at high speed, and when the rotating body is stopped, the rotating body, that is, the bearing bush member 45 and the upper and lower conical bearing members 42 No pressure is generated in the gap between the structure 44 consisting of) 43 and the shaft 41. Accordingly, when the rotating body is stopped, the bearing bush member 45 and the structure 44 are in contact with each other, and in such a state, when the rotating body rotates and pressure is generated, the rotating body rises and the bearing bush member ( 45 and the structure 44 are again in a non-contact state. However, there is a possibility that the bearing contact is reduced until the rotor is floated, and as the bearing clearance decreases, the wear and friction torque caused by the contact are increased to adversely affect the performance of the system. However, in the bearing structure of the present invention, in view of this point, as described above, the conical inclined surface portions of the upper and lower conical bearing members 42 and 43 and the inclined surface portions of the bearing bush members 45 facing each other are the same. By rotating the magnetic thin films 42m (43m) (45m) (45m ') so that the polarities face each other, the rotor is formed by mutual repulsive force of the magnetic force by the magnetic thin films 42m (43m) (45m) (45m'). By raising the pressure, wear and friction torque caused by contact can be prevented even when the rotating body is stopped. Of course, the magnetic force by such magnetic thin films 42m, 43m, 45m, 45m 'is preliminarily set to have a value such that there is no risk of losing magnetic recording information on the magnetic disk 12 due to leakage of the magnetic force. After experimenting, it is set to an appropriate value.
    As described above, the rotor supporting pneumatic hydrodynamic bearing structure according to the present invention supports the rotating body by non-contact by pneumatic hydrodynamic bearings rather than by conventional ball bearings, thereby preventing vibration and noise when using ball bearings. In this way, it is possible to realize the demand for ultra-high speed and ultra-precision rotation. In addition, since the magnetic thin film is coated on the pneumatic bearing surface, it is possible to improve the durability of the bearing by preventing the contact phenomenon from the start of the rotating body to the rise and rise. In addition, since the clearance as much as the coating thickness is reduced by coating the magnetic thin film on the bearing clearance forming surface, the bearing rigidity of the pneumatic hydraulic bearing can be further enhanced, and the bearing reaction force and the bearing by the repulsive magnetic force through such magnetic thin film coating Stiffness can be increased to support the rotor system more stably.
    权利要求:
    Claims (6)
    [1" claim-type="Currently amended] An upper conical bearing member fixed to an upper end of a shaft for fixing the rotating body, the upper conical bearing member having a conical inclined surface for forming a pneumatic bearing;
    A lower conical bearing member fixed to a lower end of the shaft and having a conical inclined surface for forming an pneumatic hydrodynamic bearing; And
    The structure consisting of the upper and lower conical bearing members and the shaft is spaced apart by a predetermined gap so as to surround the structure in the radial direction of the shaft, and form a pneumatic hydrodynamic bearing by the gap with the structure and fix the rotor on the outer circumferential surface thereof. A pneumatic hydrodynamic bearing structure for supporting a rotating body, characterized in that it comprises a cylindrical bearing bush member.
    [2" claim-type="Currently amended] The method of claim 1,
    The convex inclined surface portion of the upper and lower conical bearing members and the conical inclined surface portion of the bearing bush member facing the inclined surface portion are respectively coated with a magnetic thin film.
    [3" claim-type="Currently amended] The method of claim 2,
    The magnetic thin film is a pneumatic hydrodynamic bearing structure, characterized in that the magnetic poles facing each other are the same polarity.
    [4" claim-type="Currently amended] The method of claim 2 or 3,
    The magnetic thin film is a pneumatic hydrodynamic bearing structure for supporting the rotor, characterized in that the coating having a thickness of 1 ~ 2㎛.
    [5" claim-type="Currently amended] The method of claim 1,
    The outer circumferential surface of the shaft between the upper and lower conical bearing members fixed to the shaft is formed as a curved surface of a sinusoidal waveform having a predetermined period and amplitude.
    [6" claim-type="Currently amended] The method of claim 1,
    The inner circumferential surface of the bearing bush member facing the outer circumferential surface of the shaft between the upper and lower conical bearing members fixed to the shaft is formed with a curved surface of a sine wave waveform having a predetermined period and amplitude. Structure.
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    同族专利:
    公开号 | 公开日
    KR100513708B1|2005-12-21|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1997-10-29|Application filed by 이형도, 삼성전기 주식회사
    1997-10-29|Priority to KR1019970056023A
    1999-05-15|Publication of KR19990034418A
    2005-12-21|Application granted
    2005-12-21|Publication of KR100513708B1
    优先权:
    申请号 | 申请日 | 专利标题
    KR1019970056023A|KR100513708B1|1997-10-29|1997-10-29|Hydrodynamic air bearing structure for supporting a rotating body|
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