JP4194348B2 - Recording disk drive motor and recording disk drive apparatus - Google Patents

Recording disk drive motor and recording disk drive apparatus Download PDF

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Publication number
JP4194348B2
JP4194348B2 JP2002334451A JP2002334451A JP4194348B2 JP 4194348 B2 JP4194348 B2 JP 4194348B2 JP 2002334451 A JP2002334451 A JP 2002334451A JP 2002334451 A JP2002334451 A JP 2002334451A JP 4194348 B2 JP4194348 B2 JP 4194348B2
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Japan
Prior art keywords
recording disk
thrust
rotor
radial
bracket
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JP2002334451A
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JP2004173377A (en
Inventor
覚 袖岡
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日本電産株式会社
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/72Sealings
    • F16C33/74Sealings of sliding-contact bearings
    • F16C33/741Sealings of sliding-contact bearings by means of a fluid
    • F16C33/743Sealings of sliding-contact bearings by means of a fluid retained in the sealing gap
    • F16C33/745Sealings of sliding-contact bearings by means of a fluid retained in the sealing gap by capillary action
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C17/00Sliding-contact bearings for exclusively rotary movement
    • F16C17/10Sliding-contact bearings for exclusively rotary movement for both radial and axial load
    • F16C17/102Sliding-contact bearings for exclusively rotary movement for both radial and axial load with grooves in the bearing surface to generate hydrodynamic pressure
    • F16C17/107Sliding-contact bearings for exclusively rotary movement for both radial and axial load with grooves in the bearing surface to generate hydrodynamic pressure with at least one surface for radial load and at least one surface for axial load
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16CSHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2370/00Apparatus relating to physics, e.g. instruments
    • F16C2370/12Hard disk drives or the like

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a drive motor for a recording disk that can obtain stable rotation though simple in constitution and is reducible in thickness, and to obtain a recording disk drive unit reduced in thickness and high in reliability. <P>SOLUTION: Oil is continuously held in a radial micro gap and in a thrust micro gap, a pair of radial bearings are arranged in the axial direction so as to be apart from each other between the external peripheral face of a shaft and the internal peripheral face of a rotor, and a thrust bearing is arranged between the thrust face of a bracket and the thrust face of the rotor. Herring bone grooves of unbalanced shapes that induce the oil to flow in the axial direction toward sides opposing each other are formed as dynamic pressure generation grooves at the pair of radial grooves, and a dynamic pressure generation groove of a shape that induces the oil to flow toward the inside of the radial direction is formed at the thrust bearing. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording disk drive motor and a recording disk drive apparatus using a hydrodynamic bearing using oil as a working fluid, which is used for rotating a recording disk such as a hard disk.
[0002]
[Prior art]
Due to the recent trend toward downsizing and thinning of devices such as personal computers on which recording disk drive devices are mounted, and the diversification of products used such as application to small devices such as digital cameras of recording disk drive devices, The motor itself that is driven to rotate is also required to be reduced in size and thickness.
[0003]
As a small and thin motor for driving a recording disk for rotating a recording disk such as a hard disk, a fixed shaft, a bracket fixed to one end of the shaft, and a rotor hub rotatably supported by the shaft and the bracket A rotor magnet mounted on the rotor hub and a stator mounted on the rotor magnet so as to face the rotor magnet in a radial direction, and the axial end surface of the rotor hub is a minute one that holds oil between the axial end surface of the bracket. It has a thrust surface that forms a thrust gap, whereby a thrust bearing is formed between the rotor hub and the bracket, and the through hole of the rotor hub is a radial that holds oil between the outer peripheral surface of the shaft. It has an inner peripheral surface that forms a minute gap, and a radius between the rotor hub and the shaft. Recording disk drive motor bearing portion is formed has been known (for example, see Patent Document 1).
[0004]
Since the hydrodynamic bearing device for the recording disk drive motor described above does not require the use of a thrust plate for constituting the thrust bearing portion, the portion occupied by the thrust bearing structure in the axial direction can be reduced, It is possible to reduce the thickness of the entire motor, or to sufficiently secure the axial height of the radial bearing portion in a motor having a constant axial height.
[0005]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 2000-350408 (page 5-7, FIG. 1-3)
[0006]
[Problems to be solved by the invention]
However, in the structure in which the radial load acting on the rotor is supported by one radial bearing portion as in the recording disk drive motor disclosed in Patent Document 1, the radial total load is only at one point in the radial minute gap. Will be supported. For this reason, when trying to cope with high speed rotation, the rigidity as a bearing tends to be insufficient. In addition, when a pair of radial bearing portions is provided to enhance the bearing rigidity, the internal pressure of the oil held between the radial bearing portions becomes a negative pressure equal to or lower than the atmospheric pressure.
[0007]
As is well known, when the internal pressure of oil becomes negative, the air dissolved in the oil appears as bubbles. If air bubbles appear in the oil held in the bearing portion and stay there, leakage of oil due to changes in the external environment of the bearing such as temperature and pressure, and abnormal vibration due to contact between the dynamic pressure generating groove and the air bubbles occur. Further, since bubbles are aggregated, the oil is divided, and as a result, various adverse effects such as seizure of the bearing portion are caused by the metal contact generated as a result. Therefore, it is necessary to solve the problem. However, if an outside air communication hole or the like for discharging air bubbles is formed between the radial bearing portions, the number of processing steps increases and the cost of the motor increases.
[0008]
In addition, by not using a thrust plate, it is necessary to provide a separate retaining structure for the rotor shaft, but the conventional retaining structure for the rotor shaft is fixed to the tip of the shaft and faces the rotor in the axial direction. Since it is a ring, it is becoming difficult to meet the demand for further thinning of the motor while ensuring the effective area of the radial bearing portion and ensuring the predetermined bearing rigidity.
[0009]
SUMMARY OF THE INVENTION An object of the present invention is to realize a recording disk drive motor that can obtain a stable rotation while having a simple configuration and can be thinned.
[0010]
Another object of the present invention is to realize a thin and highly reliable recording disk drive device.
[0011]
[Means for Solving the Problems]
Claim 1 of the present invention is a radial in which oil is held between a fixed shaft, a bracket fixed to one end of the shaft, and a through-hole through which the shaft passes, and an outer peripheral surface of the shaft. A recording disk drive motor comprising: an inner peripheral surface facing through a minute gap; and a rotor having a thrust surface opposed through a thrust minute gap in which oil is held between the thrust surface of the bracket. The oil is continuously held in the radial minute gap and the thrust minute gap without interruption, and a radial bearing portion is provided between the outer peripheral surface of the shaft and the inner peripheral surface of the rotor. A pair is provided apart in the axial direction, and a thrust bearing portion is provided between the thrust surface of the bracket and the thrust surface of the rotor, In the pair of radial bearing portions, unbalanced herringbone grooves for inducing axial flow toward the opposite sides to the oil are formed as dynamic pressure generating grooves, and the thrust bearing portions Is formed with a dynamic pressure generating groove having a shape that induces a flow toward the radially inward side with respect to the oil, and the bracket has an outer peripheral side of an axial surface constituting the thrust bearing portion, A cylindrical member having an annular protrusion protruding radially outward is provided, and the rotor is a ring member having a portion located on the axial bracket side of the annular protrusion and facing the annular protrusion in the axial direction. With
The annular protrusion and the ring member constitute a retaining structure for restricting the rotor from moving in the axial direction relative to the shaft .
[0014]
According to a second aspect of the present invention, in the recording disk driving motor according to the first aspect, a concave portion recessed in the axial direction is formed on an outer peripheral side of the thrust surface on a side surface of the axial bracket of the rotor, and the cylindrical wall A radial surface of the concave portion that is radially opposed to the inner peripheral surface of the inner surface of the concave portion is formed as an inclined surface that is inclined so that an outer diameter thereof is reduced as it is spaced apart from the thrust surface in the axial direction. The inner peripheral surface of the cylindrical wall functions as a seal portion where an end of the oil on the thrust bearing portion side is located.
[0015]
Claim 3 of the present invention, there is provided a recording disk drive motor according to claim 2, wherein the rotor has a rotor magnet is fixed to the bracket magnetic circuit facing the rotor magnet in the radial direction The magnetic circuit portion, the retaining structure, the seal portion, and the radial bearing portion positioned on the thrust bearing portion side of the pair of radial bearing portions, It is characterized by being arranged in parallel in the radial direction.
[0016]
Claim 4 of the present invention, a recording disk having a housing, a spindle motor for rotating the inside fixed recording disk of the housing, and an information access means for reading writing or information to the required position of the recording disc It is a drive device, The recording disk drive motor in any one of Claim 1 thru | or 3 is used as said spindle motor, It is characterized by the above-mentioned.
[0017]
By the way, the invention described in the claims relates to the configuration according to the embodiment of the present invention, and in order to avoid duplicate description, the operational effects and the principle of the configuration of the invention according to each claim are as follows. The embodiments of the present invention and the effects of the invention will be described in detail below.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
(1) Structure of Entire Motor Hereinafter, embodiments of a recording disk driving motor according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following examples.
[0019]
FIG. 1 is a vertical cross-sectional view schematically showing a main configuration of a main part of a recording disk driving motor according to the present invention. In FIG. 1, a recording disk driving motor 1 is a small and thin motor for rotating a small recording disk (for example, 1 inch × 1 disk).
[0020]
The recording disk drive motor 1 mainly includes a fixed shaft 2, a bracket 3 to which the shaft 2 is fixed, a recording disk (shown as a disk plate 53 in FIG. 4) that is rotatably supported by the shaft 2 and the bracket 3. ), A cylindrical rotor magnet 5 fixed to the outer peripheral surface of the rotor 4, and a stator fixed to the bracket 3 and facing the rotor magnet 5 in a radial direction through a predetermined gap. 6.
[0021]
The bracket 3 includes a first bracket 7 that is a disk-like member to which the lower end portion of the shaft 2 is fixed, and a second bracket 8 that is fixed to the first bracket 7. The first bracket 7 has a thrust surface 4a that is axially opposed to a thrust surface 4b of the rotor 4 to be described later, and the second bracket 8 is a center where the outer peripheral portion of the first bracket 7 is fitted and fixed. It has an opening and a circular recess 8a to which the stator 6 is fixed. The second bracket 8 may be integrated with a base member that forms a part of the housing of the recording disk drive device.
[0022]
Next, referring to FIG. 2, the rotor 4 is a cylindrical member having a through hole through which the shaft 2 is penetrated and having a relatively large radial width. The inner peripheral surface 4a of the through hole of the rotor 4 faces the outer peripheral surface 2a of the shaft 2 via a radial minute gap. In addition, a thrust surface 4b extending radially outward from the lower end in the axial direction of the inner peripheral surface 4a of the rotor 4 is formed. Further, the rotor 4 is provided with an annular step 4c continuous with the outer peripheral surface to which the inner peripheral surface of the rotor magnet 5 is fixed. The bracket side surface of the step 4c and the lower side of the inner peripheral surface of the rotor magnet 5 are provided. An annular concave portion 9 that is recessed in the axial direction is formed on the outer peripheral side of the thrust surface 4 b by the bracket side surface of the step portion 4 c and the outer peripheral surface continuous to the thrust surface 4 b of the rotor 4.
[0023]
(2) Structure of the hydrodynamic bearing Hereinafter, the hydrodynamic bearing for rotatably supporting the rotor 4 with respect to the shaft 2 will be described while explaining the structure and relationship of each member. The dynamic pressure bearing is composed of radial bearing portions 10 and 11 and a thrust bearing portion 12.
[0024]
As shown in FIG. 2, the radial minute gap formed between the inner peripheral surface 4 a of the rotor 4 and the outer peripheral surface 2 a of the shaft 2, the thrust surface 4 b of the rotor 4, and the thrust surface 7 a of the first bracket 7 In the thrust minute gap formed between the two, the oil 17 is continuously held by capillary action. Dynamic pressure generating grooves 10a and 11a are formed on the inner peripheral surface 4a of the rotor 4 so as to be separated from each other in the axial direction, and an upper radial bearing portion 10 and a lower radial bearing portion 11 are formed between the outer peripheral surface 2a of the shaft 2. Yes. A dynamic pressure generating groove 12 a is formed on the thrust surface 4 b of the rotor 4, and a thrust bearing portion 12 is formed between the thrust surface 7 a of the first bracket 7.
[0025]
As shown in FIG. 3A, the dynamic pressure generating groove 10a of the upper radial bearing portion 10 is a herringbone groove. This herringbone groove is formed by connecting spiral grooves in opposite directions to each other. When the rotor 4 rotates, the upper spiral groove 10a1 is formed so as to induce the oil 17 to flow toward the thrust bearing 12 side. It is longer in the axial direction than the lower spiral groove 10a2. The dynamic pressure generating groove 11a of the lower radial bearing portion 11 is also a herringbone groove like the dynamic pressure generating groove 10a of the upper radial bearing portion 10, but the lower spiral groove 11a2 is the upper spiral groove 11a1. It is longer in the axial direction than That is, in the upper radial bearing portion 10, the dynamic pressure generating groove 10 a induces the flow of the oil 17 toward the thrust bearing portion 12 side, that is, the lower side in the axial direction. The fluid pressure generating groove 11a induces the flow of the oil 17 toward the upper radial bearing portion 10 side, that is, the upper side in the axial direction. As a result, the internal pressure of the oil 17 held in the region A (the portion surrounded by the alternate long and short dash line in FIG. 1) between the upper radial bearing portion 10 and the lower radial bearing portion 11 in the radial minute gap is maintained above the atmospheric pressure. As a result, the generation of bubbles is prevented.
[0026]
As shown in FIG. 3B, the dynamic pressure generating groove 12a of the thrust bearing portion 12 is a spiral groove, and this spiral groove causes the oil 17 to rotate in the direction of the shaft 2, that is, the radius when the rotor 4 rotates. It has a pump-in shape so as to generate a dynamic pressure acting inward in the direction.
[0027]
At this time, in the upper and lower radial bearing portions 10 and 11, the axial line is calculated from the sum of the pressures due to the pumping of the spiral groove portions 10 a 1 and 11 a 1 that induces the flow toward the axially lower side (the thrust bearing portion 12 side) with respect to the oil 17. The pressure obtained by subtracting the pressure due to pumping of the spiral groove portions 10a2 and 11a2 that induces the flow toward the upper side in the direction (taper seal portion 15 side) is radially inward with respect to the oil 17 provided in the thrust bearing portion 12. It is set so as to exceed the pressure due to pumping of the dynamic pressure generating groove 12a that induces the flow toward the pressure, and the pressure due to the flow of the oil 17 toward the thrust bearing portion 12 generated on the upper and lower radial bearing portions 10 and 11 side, Due to the flow of the oil 17 generated in the thrust bearing portion 12 toward the radially inward side. By the force, the rotor 4 is floated in a direction away from the bracket 3 during rotation.
[0028]
An annular thrust bush 13 made of a ferromagnetic material such as stainless steel is disposed at a portion of the second bracket 8 that faces the lower surface of the rotor magnet 5 in the axial direction. Thus, the rotor 4 is magnetically attracted to the bracket 3 side by arranging the thrust bush 13 made of a ferromagnetic material so as to face the rotor magnet 5 in the axial direction. The floating force by the upper and lower radial bearing portions 10 and 11 and the thrust bearing portion 12 acting on the rotor 4 and the magnetic attraction force by the rotor magnet 5 and the thrust bush 13 are balanced, and the rotor 4 is stabilized in the axial direction. Will be supported.
[0029]
The dynamic pressure generating groove 12a formed in the thrust bearing portion 12 connects a spiral groove portion having a large radial dimension provided on the outer peripheral side and a spiral groove portion having a small radial dimension provided on the inner peripheral side. It is also possible to form a herringbone groove having an unbalanced shape in the radial direction. In this case, the pressure due to the flow of the oil 17 from the upper and lower radial bearing portions 10 and 11 toward the thrust bearing portion 12 is imbalanced in the spiral groove portion constituting the dynamic pressure generating groove 12 a formed in the thrust bearing portion 12. It is set so as to exceed the pressure due to the flow of the oil 17 directed radially inward due to the amount.
[0030]
(3) Seal structure Next, the seal portions 14 and 15 will be described. The surface tension seal portions 22 and 24 are structures for sealing the oil 17 at both ends of the hydrodynamic bearing to prevent leakage.
[0031]
The lower seal portion 14 is a structure for preventing leakage of the oil 17 from the thrust bearing portion 12, and is configured by the rotor 4 and the first bracket 7 on the outer peripheral side of the thrust bearing portion 12. Hereinafter, the lower seal portion 14 will be described in detail while explaining the structures of the rotor 4 and the first bracket 7. As shown in FIG. 2, an annular cylindrical wall 7 b is formed on the upper surface side of the outer peripheral edge of the first bracket 7. The cylindrical wall 7 b extends upward in the axial direction and is located in the recess 9.
[0032]
The outer peripheral surface that is continuous with the bracket side surface and the thrust surface 4b of the step portion 4c in the rotor 4 is formed as an inclined surface 4d that inclines so that the outer diameter decreases as it proceeds from the thrust surface 4b toward the bracket side surface of the step portion 4c. A tapered gap is defined between the inclined surface 4d and the inner peripheral surface of the cylindrical wall 7b. The extension 15c is disposed on the inner peripheral side surface 4f and the end surface 4h with a gap therebetween. The tapered gap formed between the inclined surface 4d and the inner peripheral surface of the cylindrical wall 7b is continuous with the thrust minute gap formed by the thrust surfaces 4b and 7a of the rotor 4 and the first bracket 7, respectively. And the edge part of the oil 17 hold | maintained at a thrust micro clearance gap is hold | maintained. Specifically, the surface tension of the oil 17 and the air pressure of the outside air are balanced in a tapered gap formed between the inclined surface 4d and the inner peripheral surface of the cylindrical wall 7b. Meniscus is located.
[0033]
The upper seal portion 15 has a structure for preventing the oil 17 from leaking from the upper radial bearing portion 10 side. The upper seal portion 15 is connected to the inner peripheral surface 4b of the rotor 4 at the outer end in the axial direction of the upper radial bearing portion 10. The outer peripheral surface 2a of the shaft 2 is comprised. Specifically, on the inner peripheral surface 4 a of the rotor 4, the inclined surface 4 e is formed on the outer side in the axial direction of the upper radial bearing portion 10 so that a gap between the outer peripheral surface 2 a of the shaft 2 and the outer peripheral surface 2 a expands outward in the axial direction. In the tapered gap between the inclined surface 4e and the outer peripheral surface 2a of the shaft 2, the surface tension of the oil 17 held in the radial micro gap and the air pressure of the outside air are balanced, The meniscus of the oil 17 is located in this gap.
[0034]
As a result, even if the oil 17 tries to move further outward from the meniscus formation position of either the lower seal portion 14 or the upper seal portion 15, the meniscus formed in the other seal portion tends to balance with this. , It becomes a resistance and the movement of the oil 17 to the outside of the bearing is suppressed.
[0035]
(4) Retaining structure The retaining structure is a structure for preventing the rotor 4 from coming out of the shaft 2 in the axial direction, and is formed between the rotor 4 and the first bracket 7. Hereinafter, the retaining structure will be described in detail while explaining the structures of the rotor 4 and the first bracket 7.
[0036]
As shown in FIG. 2, a flange 7 c extending to the outer peripheral side is formed at the tip of the cylindrical wall 7 b of the first bracket 7. The radial position of the tip of the flange 7 c is on the outer peripheral side with respect to the radial direction position of the outer peripheral surface of the main body portion of the first bracket 7. An annular yoke member 16 made of a ferromagnetic material such as stainless steel is mounted on the inner peripheral surface of the rotor magnet 5 that forms the recess 9. The upper end surface of the yoke member 16 is in contact with the bracket side surface of the step portion 4c, which is the bottom surface of the recess 9, and is positioned.
[0037]
The yoke member 16 is mounted to block the leakage magnetic flux from the magnetic circuit formed between the rotor magnet 5 and the stator 6, and further, the axial center portion on the inner peripheral surface of the yoke member 16. An annular protrusion 16a extending to the inner peripheral side is formed on the lower side than the above, and the annular protrusion 16a and the flange portion 7c are engaged with each other to thereby restrict the movement of the rotor 4 in the axial direction. A stop structure will be constructed.
[0038]
With the configuration as described above, in the recording disk driving spindle motor according to the present embodiment, stable rotation can be obtained by having the upper and lower radial bearing portions 10 and 11, and the upper portion in the radial minute gap can be obtained. Since the generation of negative pressure in the region between the radial bearing portion 10 and the lower radial bearing portion 11 can be prevented, various adverse effects related to bubbles can be eliminated with a simple configuration. In addition, the lower radial bearing portion 11, the lower seal portion 14, the retaining structure, and the magnetic circuit portion including the rotor magnet 5 and the stator 6 are arranged in parallel on the same plane in the height direction of the motor. It is possible to realize a reduction in thickness, and at the same time, it is possible to secure an effective area of the radial bearing portion and a predetermined bearing rigidity within a limited dimension in the height direction.
[0039]
(5) Configuration of Recording Disk Drive Device Next, a recording disk drive device using the recording disk drive motor according to the embodiment of the present invention described above will be described with reference to FIG.
[0040]
FIG. 4 shows a schematic diagram of an internal configuration of a general disk drive device 50. The housing 51 forms a clean space with extremely small amounts of dust and the like, and a recording disk drive motor 52 having a disk-shaped disk plate 53 for storing information is installed therein. Yes. In addition, a head moving mechanism 57 that reads and writes information from and to the disk plate 53 is disposed inside the housing 51. The head moving mechanism 57 supports a head 56 that reads and writes information on the disk plate 53, and the head. The arm 55, the head 56, and the arm 55 are configured by an actuator unit 54 that moves the arm 55 to a required position on the disk plate 53.
[0041]
By using the motor 1 of the above embodiment as the recording disk drive motor 52 of such a recording disk drive device 50, a thin and highly reliable recording disk drive device can be obtained.
[0042]
The second bracket 8 of the recording disk drive motor 1 shown in FIG. 1 is directly fixed to the housing 51 or formed integrally with the housing 51, and the axial upper end of the shaft 2 (first bracket 7 1 is provided with a female screw hole 18 as shown in FIG. 1, and a male screw 57 is fastened to the female screw hole 18 via a housing 51. By adopting the fixed structure, the shaft 2 functions as a column of the recording disk drive device 50, and the robustness thereof can be improved and the durability can be improved.
[0043]
As described above, the recording disk driving motor and the recording disk driving apparatus according to the embodiment of the present invention have been described. However, the present invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the present invention. Or it can be modified.
[0044]
For example, in the illustrated embodiment, a motor in which the dynamic pressure generating groove is formed in the rotor in the radial bearing portion and the thrust bearing portion has been described as an example. Needless to say, the present invention can also be applied to a motor that forms the above.
[0045]
【The invention's effect】
In the recording disk drive motor of the present invention, by having a pair of radial bearing portions, stable rotation can be obtained, and generation of negative pressure in the region between the radial bearing portions in the radial minute gap can be prevented. Therefore, various adverse effects related to the bubbles can be eliminated with a simple configuration. In addition, the radial bearing part on the thrust bearing part side, the seal part, the retaining structure, and the magnetic circuit part made up of the rotor magnet and the stator are arranged in parallel on the same plane in the height direction of the motor, thereby reducing the thickness of the motor. As a result, it is possible to secure an effective area of the radial bearing portion and a predetermined bearing rigidity within a limited height dimension.
[0046]
Further, the recording disk drive device of the present invention can be a thin and highly reliable recording disk drive device.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view schematically showing a schematic configuration of a recording disk drive motor according to an embodiment of the present invention.
FIG. 2 is a partially enlarged view of FIG. 1, and is a longitudinal sectional view schematically showing a schematic configuration of a retaining structure.
3A is a longitudinal sectional view schematically showing the shape of a dynamic pressure generating groove formed in a radial bearing portion, and FIG. 3B is a schematic view of the dynamic pressure generating groove formed in a thrust bearing portion. It is a top view which shows a shape typically.
FIG. 4 is a schematic diagram showing a schematic configuration of a recording disk drive device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Recording disk drive motor 2 Shaft 3 Bracket 4 Rotor 10, 11 Radial bearing part 10a, 11a Herringbone groove 12 Thrust bearing part 12a Spiral groove 17 Oil

Claims (4)

  1. A fixed shaft, a bracket fixed to one end of the shaft, and a through-hole through which the shaft passes are formed, and are opposed to each other through a radial minute gap that holds oil between the outer peripheral surface of the shaft. A recording disk drive motor comprising a rotor formed with a thrust surface facing through a thrust minute gap in which oil is held between a peripheral surface and a thrust surface of the bracket,
    In the radial minute gap and the thrust minute gap, the oil is continuously held without interruption,
    Between the outer peripheral surface of the shaft and the inner peripheral surface of the rotor, a pair of radial bearing portions are provided apart in the axial direction, and between the thrust surface of the bracket and the thrust surface of the rotor, A thrust bearing is provided,
    In the pair of radial bearing portions, unbalanced herringbone grooves for inducing axial flow toward the mutually opposing sides with respect to the oil are formed as dynamic pressure generating grooves, and the thrust bearing portion Is formed with a dynamic pressure generating groove having a shape that induces a flow toward the radially inward side with respect to the oil,
    The bracket is provided with a cylindrical wall having an annular protrusion protruding outward in the radial direction on the outer peripheral side of the axial direction surface constituting the thrust bearing portion,
    The rotor includes a ring member having a portion located on the axial bracket side from the annular protrusion and facing the annular protrusion in the axial direction;
    A recording disk driving motor, wherein the annular protrusion and the ring member constitute a retaining structure for restricting the rotor from moving in the axial direction relative to the shaft.
  2.   A concave portion recessed in the axial direction is formed on the outer peripheral side of the thrust surface on the side surface of the axial bracket of the rotor, and the radial surface of the concave portion facing the inner peripheral surface of the cylindrical wall in the radial direction is the thrust surface. Is formed on an inclined surface that is inclined so that the outer diameter thereof is reduced as it is separated from the axial direction from the axial direction. The recording disk driving motor according to claim 1, wherein the recording disk driving motor functions as a seal portion positioned.
  3. A rotor magnet is fixed to the rotor,
    The bracket is arranged with a stator that forms a magnetic circuit portion facing the rotor magnet in the radial direction,
    The magnetic circuit part, the retaining structure, the seal part, and the radial bearing part located on the thrust bearing part side of the pair of radial bearing parts are arranged in parallel in the radial direction. The recording disk drive motor according to claim 1, wherein:
  4. A recording disk drive device comprising a housing, a spindle motor fixed inside the housing and rotating the recording disk, and information access means for writing or reading information at a required position of the recording disk,
    4. A recording disk drive apparatus according to claim 1, wherein the recording disk drive motor according to claim 1 is used as the spindle motor.
JP2002334451A 2002-11-19 2002-11-19 Recording disk drive motor and recording disk drive apparatus Expired - Fee Related JP4194348B2 (en)

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