JP3424739B2 - Recording disk drive motor and recording disk drive provided with the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording disk drive motor using a dynamic pressure bearing by a lubricating fluid used for rotationally driving a recording disk such as a hard disk, and a recording disk drive device equipped with this motor. .

[0002]

2. Description of the Related Art Conventionally, in order to relatively rotatably support a shaft and a sleeve member surrounding the shaft,
A motor using a dynamic pressure bearing that utilizes the fluid pressure of a lubricating fluid interposed between the two is used to drive the recording disk in rotation.

In such a fluid dynamic bearing, as a means for supporting a load in the radial direction (radial direction), a sleeve which faces the radial direction with a minute gap between the shaft and the outer peripheral surface of the shaft. A lubricating fluid is filled between the inner peripheral surfaces of the members, and a dynamic pressure generating groove formed on the outer peripheral surface of the shaft and / or the inner peripheral surface of the sleeve member generates a dynamic pressure in the lubricating fluid during rotation of the rotor hub. In addition to having a radial bearing part for supporting the load in the thrust direction (axial direction), there is a minute gap between the disk-shaped thrust plate fixed to the end of the shaft and the upper and lower surfaces of this thrust plate. The lubricating fluid is filled between the upper surface of the step formed on the sleeve member facing the axial direction and the lower surface of the thrust bushing, and the upper and lower surfaces of the thrust plate and Or in the rotor hub by the upper surface and a lower surface formed dynamic pressure generating grooves of the thrust bush of the step rotation, with the thrust bearing portion to cause dynamic pressure in the lubricating fluid.

[0004]

In the conventional fluid dynamic bearing as described above, when the dynamic pressure generating grooves of the radial and thrust bearing portions have a herringbone shape, for example,
Since dynamic pressure acts from the upper and lower parts in the axial direction toward the center of the herringbone groove, the pressure due to the lubricating fluid is lower near the boundary between the radial bearing and the thrust bearing, which is the bearing end of the radial bearing. Since air bubbles tend to exist, the bubbles mixed during the filling of the bearing fluid with the bearing fluid or during operation of the bearing are retained in the vicinity of this boundary area, and these bubbles thermally expand when the motor is hot, causing the lubricating fluid to flow to the outside of the bearing. Problems such as leakage occur.

In order to prevent bubbles from staying near the boundary between the radial bearing portion and the thrust bearing portion,
When the dynamic pressure generating grooves of the respective bearings are formed in a spiral shape so that dynamic pressure acts on the radial bearings in the direction of the thrust bearings and in the thrust bearings in the direction of the radial bearings, Although it can be prevented, it becomes difficult to obtain the dynamic pressure necessary for the radial bearing portion for axially supporting the rotation of the rotor hub, which causes the deterioration of the rotation accuracy of the motor.

The present invention solves the above-mentioned conventional problems, and can prevent bubbles from staying at the boundary between the radial bearing portion and the thrust bearing portion without impairing the rotational accuracy of the motor. It is intended to provide a disk drive motor.

[0007]

In order to solve the above problems, a recording disk drive motor according to the present invention comprises a stationary member,
A rotating member on which at least one recording disk that is relatively rotatable with respect to the stationary member is mounted, a rotor magnet fixed to the rotating member, and a rotary driving force generated in cooperation with the rotor magnet. For this purpose, a stator disposed on the stationary member, a radial bearing portion that generates a supporting force for supporting the radial load by the rotation of the rotating member, and a radial bearing portion that supports the thrust load by the rotation of the rotating member. In a recording disk drive motor comprising a thrust bearing portion that generates a supporting force and a lubricating fluid retained by the radial bearing portion and the thrust bearing portion, the lubricating fluid retained by the radial bearing portion is
Generates dynamic pressure to move toward the thrust bearing
Radius with herringbone shape unbalanced in the axial direction
Groove for generating dynamic pressure and the moisture retained in the thrust bearing portion.
The lubricating fluid is moved toward the rotation axis of the rotating member.
A thrust dynamic pressure generating groove for generating a dynamic pressure
And the thrust bearing retained in the bearing
Is continuously retained between the lubricating fluid retained in the
And a lubricating fluid .

In this structure, the dynamic pressure generating groove of the radial bearing portion has a herringbone shape which is unbalanced in the axial direction so that the generated dynamic pressure generates a dynamic pressure that moves the lubricating fluid toward the thrust bearing portion. The dynamic pressure generating groove of the thrust bearing has a shape that generates dynamic pressure that causes the lubricating fluid to move in the direction of the rotation axis of the rotating member, so that the dynamic pressure generated in the radial and thrust bearings is at the boundary of each. The air bubbles act toward each other and the bubbles are prevented from staying in this portion.

Another recording disk driving motor of the present invention is a stationary member, a rotating member on which at least one recording disk is mounted that is rotatable relative to the stationary member, and the rotating member. A rotor magnet fixed to the
A stator disposed on the stationary member for generating a rotational driving force in cooperation with the rotor magnet; a radial bearing portion for generating a supporting force for supporting a radial load by rotation of the rotating member; and a thrust bearing portion to produce a support force for supporting the thrust direction load by the rotation of the rotary member, the recording disk drive motor comprising a lubricating fluid that is held in the radial bearing portion and said thrust bearing portion, the Formed on stationary member
Up and down in the axial direction of the air intervening part that communicates with the communication hole for outside air communication
A pair of the radial bearing parts, and the radial part
The lubricating fluid held in the bearing
The amber in the axial direction to generate the dynamic pressure
Lance herringbone shaped groove for radial dynamic pressure generation
The lubricating fluid held in the thrust bearing
Generates dynamic pressure that moves the rotary member toward the axis of rotation.
The thrust dynamic pressure generating groove and the radial bearing
Retained by the lubricating fluid and the thrust bearing portion
A lubricating fluid continuously retained between the lubricating fluid,
And characterized in that it comprises a.

As described above, by forming a pair of radial bearing portions in the axial direction, a communication hole communicating between the radial bearing portion and the outside air is opened in order to discharge bubbles accumulated between the upper and lower radial bearing portions to the outside of the bearing. However, a sufficient bearing span can be ensured in the radial bearing portion, and the rotation accuracy of the motor can be further improved.

The term "outside air" as used herein refers to the atmosphere outside the minute gap of the radial bearing portion, which may be inside or outside the motor or inside or outside the device incorporating the motor. Further, it does not matter whether the pressure of the outside air is atmospheric pressure or not.

The dynamic pressure generating groove formed in the thrust bearing portion has a spiral shape or a herringbone shape that is unbalanced in the radial direction, so that the lubricating fluid is directed toward the rotating shaft center of the rotating member. A dynamic pressure to move can be generated.

The magnetic bias means that the rotating member is attracted or repelled by the magnetic force with respect to the stationary member to obtain an urging force in its acting direction. The magnetic bias is opposed to the rotor magnet in the axial direction, for example. This can be realized by disposing a magnetic member at the position of the stationary member or by disposing magnets magnetized with the same or different polarities at the portions of the stationary member and the rotating member that face each other in the axial direction. In the recording disk drive motor of the present invention, the load bearing force in the thrust direction is enhanced by magnetically biasing the rotating member in the axial direction.

The rotating member is integrally formed in a disk-shaped portion, a cylindrical portion extending in the axial direction from the outer peripheral portion of the disk-shaped portion and fixed to the inner peripheral portion of the rotor magnet, and a substantially central portion of the disc-shaped portion. The stationary member is provided with a sleeve member having a hollow portion which is opposed to the shaft member in the radial direction with a minute gap and has a hollow portion open at both ends in the axial direction, and the lubricating fluid is provided with the shaft member and the sleeve member. The radial bearing portion is constituted by being held in a minute gap between the radial bearing portion and the.

In this case, the disk-shaped portion of the rotating member of the motor constitutes a part of the thrust bearing portion, so that the motor can be made thin and a sufficient area of the portion functioning as the thrust bearing portion can be secured. You can
The rotation accuracy of the motor is improved. Further, since it is not easily affected by errors in the accuracy and strength of the respective members constituting the thrust bearing portion and the fastening portions such as the disc-shaped portion and the shaft member, the process control becomes easy and the productivity of the motor can be improved. At the same time, the minute gap between the thrust bearing portions can be set small (narrow) within the allowable range of the surface accuracy of the lower surface of the disk-shaped portion of the rotary member that constitutes the thrust bearing portion and the axially upper end surface of the sleeve member. Therefore, the bearing rigidity of the thrust bearing portion can be increased and the thrust load supporting force can be improved.

The thrust bearing portion is provided with a thrust plate projecting outward in the radial direction at one end of the shaft member, and a thrust plate at one end of the sleeve member facing the outer peripheral surface of the thrust plate. An annular step portion to be included is formed, and one end of the hollow portion of the sleeve member is sealed by a cover member, and the step portion, the cover member, and the thrust plate are formed to face each other in the axial direction. It is also possible to configure by holding the lubricating fluid in at least a part of the minute gap.

The axially unbalanced herringbone dynamic pressure generating groove formed in the radial bearing portion is formed by combining a pair of spiral grooves in the axial direction. In this case, the thrust is used. By setting the axial dimension of the spiral groove located on the bearing side to one half or less of the axial dimension of the other spiral groove, air bubbles are retained at the boundary between the radial bearing section and the thrust bearing section. It is possible to obtain a sufficient radial load bearing force while preventing this.

Further, the recording disk drive device of the present invention is
By using the recording disk drive motor described above, the same effects as those of the recording disk drive motor according to the first to sixth aspects can be obtained.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a recording disk drive device and a recording disk drive motor according to the present invention will be described with reference to the drawings, but the present invention is limited to the respective embodiments shown below. is not.

FIG. 1 is a vertical cross-sectional view schematically showing the structure of a main part of a recording disk drive device of the present invention.

In FIG. 1, this recording disk drive device includes a base member 202 for supporting a recording disk drive motor, and an upper lid portion 206 surrounding the recording disk drive motor together with the base member 202 to form a clean space 204 inside. And a clamp member 212 fixed to the rotor hub of the recording disk drive motor by a screw 210 to hold a recording disk 208 such as a hard disk held by the rotor hub of the recording disk drive motor. .

Next, an embodiment of a recording disk drive motor used in the recording disk drive device shown in FIG. 1 will be described with reference to FIGS. 2A, 2B and 3.

FIG. 2A shows a first recording disk drive motor used in the recording disk drive apparatus of the present invention.
2B is a vertical cross-sectional view schematically showing the configuration of a main part of the embodiment of FIG. 2, and FIG. 2B shows a herringbone-shaped groove formed in the radial bearing portion of the recording disk drive motor shown in FIG. It is sectional drawing shown.

In FIG. 2 (a), the recording disk drive motor 1 includes a substantially disc-shaped upper wall portion 2a and a cylindrical peripheral wall portion 2b which hangs downward from an outer peripheral edge portion of the upper wall portion 2a.
And a flange portion 2c that projects radially outward from the lower end portion of the outer peripheral surface of the peripheral wall portion 2b and mounts the recording disk 208 shown by the two-dot chain line in FIG. 2A, One end of the rotor hub 2 is externally fitted and fixed to the center of the upper wall 2a of the rotor hub 2, and the shaft 4 forms a part of a rotating member, and a hollow cylindrical support member 6 rotatably supports the shaft 4. A disk-shaped cover 8 fitted to the lower end of the inner periphery of the support member 6, a holding cylinder 10 as a holding body for holding the support member 6, a bracket 12 including the holding cylinder 10, and a rotor hub 2. Upper wall 2a and shaft 4
And a lubricating fluid 14 such as a lubricating oil held by capillary action in a minute gap formed between the support member 6 and the cover 8,
A radial bearing portion 18 that generates a radial load supporting pressure by the action of a herringbone-shaped groove 16 formed on the inner peripheral surface of the support member 6 that faces the outer peripheral surface of the shaft 4 in the radial direction.
And the upper wall portion 2 that axially opposes the upper end surface of the support member 6.
Thrust bearing portion 22 for generating thrust load supporting pressure by the action of spiral groove 20 formed on the lower surface of a
And the motor coil 24 arranged on the outer peripheral side of the holding cylinder 10.
And a rotor magnet 26 fixed to the inner peripheral surface of the peripheral wall portion 2b of the rotor hub 2 for rotating the rotor hub 2 and the shaft 4 in the support member 6 and the cover 8 in cooperation with the motor coil 24. is doing. Bracket 1
2 is fixed to the base member 202 shown in FIG.

The herringbone-shaped groove 16 formed in the radial bearing portion 18 is formed by connecting spiral grooves 16a and 16b in opposite directions to each other as shown in FIG. 2 (b). Fig. 2 when rotating
As shown by an arrow A in (a), the thrust bearing portion 22
It is unbalanced in the axial direction so as to generate a dynamic pressure that moves the lubricating fluid 14 toward. Further, the spiral groove 20 formed in the thrust bearing portion 22 moves the lubricating fluid 14 in the axial direction of the shaft 4 as indicated by an arrow B in FIG. 2A when the rotor hub 2 and the shaft 4 rotate. It is designed to generate dynamic pressure.

In this case, the herringbone-shaped groove 16 formed in the radial bearing portion 18 has the axial dimension of the spiral groove 16a located on the thrust bearing portion 22 side relative to the axial dimension of the other spiral groove 16b. It is possible to prevent air bubbles from staying by generating a low pressure portion near the boundary between the radial bearing portion 18 and the thrust bearing portion 22 while obtaining a sufficient radial load supporting force by setting the amount to 1/2 or less.

The support member 6 is formed of a metal material such as copper or copper alloy or stainless steel, and a communication passage 28 for connecting the radial bearing portion 18 to the outside air is provided at the axial end portion of the radial bearing portion 18. It is formed at one end. The communication passage 28 has at least the first communication passage 28 a formed in the axial direction on the inner peripheral surface of the holding cylinder 10 holding the support member 6 so as to open to the upper end surface of the holding cylinder 10 and at least the radial bearing portion 18. A second communication passage 28b is formed in the lower end surface of the support member 6 in the radial direction so as to open at one axial end portion and connect the first communication passage 28a and the radial bearing portion 18 to each other. The radial bearing portion 18 is open to the outside air via the communication passage 28, and the bubbles mixed in the lubricating fluid 14 during the filling of the lubricating fluid 14 or the rotation of the motor are used to let the outside of the bearing pass through this hole. The discharge of the lubricating oil 14 prevents the lubricating fluid 14 from leaking to the outside of the bearing due to thermal expansion of the bubbles due to the temperature rise of the motor. In addition, in FIG.
Although only one communication passage 28 is shown, a plurality of communication passages 28 may be formed in the circumferential direction, for example.

On the lower surface of the upper wall portion 2a of the rotor hub 2, there is a circumferential projection 2d which faces the outer peripheral surface of the support member 6 with a gap.
Is formed, and a taper-shaped seal portion 30 is provided at the outer end of the thrust bearing portion 22 in the radial direction so that the inner peripheral surface of the circumferential protrusion 2d and the support member 6 cooperate to form a seal structure. . The tapered seal portion 30 is provided with the circumferential projection 2
The gap between d and the outer peripheral surface of the support member 6 is composed of an inclined surface formed on the outer peripheral surface of the support member 6 so as to expand downward in the axial direction. The surface tension of the lubricating fluid 14 held in the portion 22 and the external pressure are balanced, and the lubricating fluid 14 is prevented from leaking to the outside of the bearing. Further, the tapered seal portion 30 may be formed of an inclined surface formed on the upper end surface of the support member 6 so that the minute gap of the thrust bearing portion 22 expands outward in the radial direction. In addition,
In order to prevent the occurrence of a so-called oil migration phenomenon in which the lubricating fluid 14 leaks to the outside of the bearing through the inner peripheral surface of the circumferential protrusion 2d or the outer peripheral surface of the support member 6 that constitutes the tapered seal portion 30, the tapered shape is required. It is desirable to apply an oil repellent made of, for example, a fluorine-based material to the seal portion 30.

An annular notch 4a is formed at the lower end of the shaft 4 in the axial direction, and the annular notch 4 is formed.
A ring-shaped member 32 that projects radially outward from the outer peripheral surface of the shaft 4 is fixed to a, and an annular recess 6a is formed on the inner peripheral surface of the support member 56 that corresponds to this ring-shaped member 32. The structure for preventing the shaft 4 from coming off is configured by fitting the ring-shaped member 32 and the annular recess 6a together. By having the retaining structure in the minute gap as described above, the play in the axial direction of the rotor hub 2 is reduced, the movable amount of the rotor hub 2 is limited even when a shock is applied to the motor, and the recording mounted on the rotor hub 2 is performed. It is possible to prevent the disk 208 and the head (not shown) that reads and writes information from the recording disk 208 from coming into contact with each other and damaging them.

The ring-shaped member 32 is fixed so as to protrude somewhat downward in the axial direction from the lower end portion of the shaft 4, and the minute gap between the end surface of the shaft 4 and the cover 8 is the minute gap of other portions. Lubricating fluid 1 set relatively larger than
4 functions as a reservoir. The lubricating fluid 14 stored in the reservoir is supplied when the amount of the lubricating fluid 14 in the bearing decreases, and the function of the bearing can be stably maintained for a long period of time.

With the above structure, the rotor hub 2 and the shaft 4 are rotationally driven in the support member 6 and the cover 8 by energizing the motor coil 24. At this time, in the thrust bearing portion 22, the upper wall of the rotor hub 2 is rotated. The lubricating fluid 14 in the gap between the portion 2a and the support member 6 generates thrust load supporting pressure due to the action of the spiral groove 20 due to the rotation of the rotor hub 2, and acts to float the rotor hub 2 and the shaft 4. Further, in the radial bearing portion 18,
The lubricating fluid 14 in the gap between the shaft 4 and the support member 6 is
The rotation of the shaft 4 generates a radial load supporting pressure by the action of the herringbone-shaped groove 16 and acts to align the shaft 4.

At this time, a magnetic biasing force is applied to the rotor hub 2 and the shaft 4 in the direction of the base member 12, and the thrust load supporting pressure is balanced and balanced.

As described above, the thrust bearing portion 22 is formed between the rotor hub 2 and the support member 6, and the rotor hub 2 itself located above the motor 1 constitutes the thrust bearing portion 22. The thrust bearing portion 22 can hold the posture of No. 2 and the minute gap formed between the outer peripheral surface of the shaft 4 and the inner peripheral surface of the support member 6 constituting the radial bearing portion 18 is made relatively large. Therefore, it is possible to reduce the processing man-hours of these members that require precise processing. In addition, since the thrust bearing portion 22 is located above the motor 1, the rotor hub 2 is not rotated during rotation.
Even if the posture of the thrust bearing portion 22 changes, the thrust bearing portion 22 is formed over a relatively wide range radially outward from the rotation axis of the shaft 4, so the thrust bearing portion 2
A restoring moment is likely to occur in 2 and it does not take time to recover the posture.

Further, since the upper wall portion 2a of the rotor hub 2 constitutes a part of the thrust bearing portion 22 and the configuration of the radial bearing 18 can be simplified, the motor 1 can be made compact and thin. It becomes possible and the cost of the motor can be reduced.

Further, the thrust bearing portion 22 is attached to the rotor hub 2
The rotor hub 2 and the shaft 4 which are provided between the upper wall portion 2a and the upper end surface of the support member 6 and in which the thrust bearing portion 22 is generated.
Since it is configured to balance the levitation force of the rotating member with a magnetic bias, it suffices to configure the thrust bearing to act only in one axial direction, and reduce the number of bearing components that require precise processing. Therefore, the process can be easily controlled, and the cost of the recording disk drive device can be reduced.

FIG. 3 is a vertical cross-sectional view schematically showing the structure of a bearing portion of a second embodiment of a recording disk drive motor used in the recording disk drive apparatus of the present invention. The same reference numerals are given to members having the same effects as those of the above-mentioned constituent members, and the description thereof will be omitted.

The recording disk drive motor 50 shown in FIG. 3 has substantially the same structure as that of the first embodiment of the present invention described above, but in the recording disk drive motor 50 of the second embodiment of the present invention. Is a shaft 54 whose one end is externally fitted and fixed to a substantially central portion of an upper wall portion 52a of the rotor hub 52, a hollow cylindrical support member 56 which rotatably supports the shaft 54, and the other of the shafts 54. A disk-shaped thrust plate 60 protruding radially outward from the outer peripheral surface of the shaft 54 fixed to the end portion of the shaft 54, and a step portion 56a formed on the inner peripheral surface of the support member 56 corresponding to the thrust plate 60. Between the disk-shaped cover 58, the shaft 54, the support member 56, the thrust plate 60, and the step portion 56a, which are fitted to the lower end of the inner periphery of the support member 56 so as to close the step portion 56a. A lubricating fluid 64 such as a lubricating oil held by a capillary phenomenon in the formed minute gap, and a herringbone-shaped groove 66 formed on the inner peripheral surface of the support member 56 radially opposed to the outer peripheral surface of the shaft 54, The thrust load is generated by the action of the pair of radial bearings 68, 69 which generate a radial load supporting force by the action of 67 and the action of the spiral groove 70 formed on the upper surface of the thrust plate 60 axially opposed to the horizontal plane of the step 56a. And a thrust bearing portion 72 that generates a supporting force.

Of the herringbone-shaped grooves 66, 67 formed in the radial bearings 68, 69, the thrust bearing 7
The radial bearing 69 located on the second side is axially arranged so that when the rotor hub 52 and the shaft 54 rotate, a dynamic pressure that moves the lubricating fluid 64 toward the thrust bearing 72 is generated as indicated by an arrow C in FIG. It is unbalanced. Further, the spiral groove 70 formed in the thrust bearing portion 72 has a dynamic pressure that moves the lubricating fluid 64 in the axial direction of the shaft 54 as shown by an arrow D in FIG. 3 when the rotor hub 52 and the shaft 54 rotate. Is to occur. The herringbone groove 66 formed in the radial bearing portion 68 is
It is formed in a state of being balanced in the axial direction so that a dynamic pressure for moving the lubricating fluid 64 in the direction of the center of is generated.

In this case, the herringbone-shaped groove 67 formed in the radial bearing portion 69 divides the axial dimension of the spiral groove located on the thrust bearing portion 72 side into two halves with respect to the axial dimension of the other spiral groove. By setting the ratio to 1 or less, it is possible to prevent a low pressure portion from being generated near the boundary portion between the radial bearing portion 69 and the thrust bearing portion 72 and to retain air bubbles while obtaining a sufficient radial load supporting force.

The support member 56 includes a radial bearing portion 66,
A first communication hole 74a opening between 67 is formed, and an annular recess 54a is formed at a position of the shaft 54 facing the opening of the first communication hole 74a, and the annular recess 54a and the support member 56 are formed. A first gas interposition part 76 in which air intervenes is formed between the first gas interposition part 76 and the inner peripheral surface. In addition, a second communication hole 74b opened between the thrust plate 60 and the cover 58 is formed, and the thrust plate 6 is formed.
On the lower surface side of 0, the second air interposition part 7 is provided between the second air interposition part 7 and the cover 58.
8 is formed. The first communication hole 74a and the second communication hole 74b communicate with the outside air via the ventilation hole 74c.

At this time, the first gas interposition part 76 and the second gas interposition part 76
The air held in the gas intervening portion 78 and the surface tension of the lubricating fluid 64 are balanced by the external pressure, and when the lubricating fluid 64 decreases due to evaporation or the like, the second gas interposing portion 78 expands. Since the lubricating fluid 64 existing in the portion other than the bearing portion is replenished to the bearing portion, the lubricating fluid 64 is always held in the bearing portion, and the reliability of the motor can be improved.

Further, by providing the radial bearing portions 68, 69 separated from each other in the axial direction, it is possible to sufficiently secure the bearing span of the radial bearings 68, 69 acting on the shaft 54 as a bearing, and improve the bearing rigidity. The stability of rotation can be improved.

In the above-described embodiments of the present invention, the recording disk drive device of the type in which the bracket 12 of the recording disk drive motor is attached to the base member 202 of the recording disk drive device has been described as an example. The base member 202 of the drive unit is the bracket 12
It goes without saying that the present invention can be applied to a so-called base-integrated recording disk drive having the function of 1.

[0044] As the fluid is interposed in the radial bearing portions 19,20,50 and the thrust bearing portion 24, 54, lubricating oil, appropriately selected based on the required load heavy supporting pressure and viscosity, etc. of a magnetic fluid, etc. Is.

Further, in the present embodiment, the recording disk drive motor provided with the thrust bearing acting in only one direction in the axial direction has been described as an example, but the thrust bearing acting in the vertical direction in the axial direction is provided. Needless to say, the present invention can be applied to a recording disk driving motor. Further, the dynamic pressure generating groove formed in the thrust bearing portion may have a herringbone shape. In that case, the herringbone-shaped groove formed in the thrust bearing portion located on the radial bearing portion side is the axial center of the shaft. It is necessary to form a dynamic pressure that moves the lubricating fluid in the direction.

[0046]

According to the recording disk drive motor and the recording disk drive apparatus of the present invention, a herringbone that is unbalanced in the axial direction is generated in the radial bearing so as to generate a dynamic pressure for moving the lubricating fluid toward the thrust bearing. Sufficient radial load support by forming a dynamic pressure generating groove in the shape and forming a dynamic pressure generating groove in the thrust bearing so that the lubricating fluid moves in the direction of the rotation axis of the rotating member. It is possible to prevent bubbles from accumulating at the boundary between the radial bearing portion and the thrust bearing portion while obtaining force.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view schematically showing a configuration of a main part of a recording disk drive device of the present invention.

FIG. 2A is a vertical cross-sectional view showing a schematic main configuration of a recording disk drive motor according to the first embodiment of the present invention, and FIG. 2B is a herringbone groove formed in a radial bearing portion. FIG.

FIG. 3 is a longitudinal sectional view showing a schematic main configuration of a bearing portion of a recording disk drive motor according to a second embodiment of the present invention.

[Explanation of symbols]

1,50 Recording disk drive motor 2,52 rotor hub 2a, 52a Upper wall part 2b peripheral wall 4,54 shaft 6,56 Support member 14,64 Lubricating fluid 18a, 68, 69 radial bearing 22,72 Thrust bearing part 24 motor coil 26 rotor magnet 208 recording disc

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G11B 19/20 F16C 17/10 F16C 33/10 H02K 7/08 H02K 21/22

Claims (8)

(57) [Claims] 1. A stationary member and a relative member with respect to the stationary member.
Is equipped with at least one rotatable recording disk
Rotating member and a rotor magnet fixed to the rotating member.
Together with the rotor magnet to generate a rotational driving force.
The stator disposed on the stationary member for
To support the radial load by rotating the rolling member
Of the rotating member and the radial bearing that generates the supporting force of
Support force to support the thrust load by rolling
The thrust bearing part, the radial bearing part and the
And a lubricating fluid held in the thrust bearing portion.
In recording disk drive motor,The lubricating fluid retained in the radial bearing is
Axial direction that generates dynamic pressure that moves toward the strike bearing
Unbalanced herringbone radial dynamic pressure
Generating groove, The lubricating fluid retained in the thrust bearing portion is
A spring that generates dynamic pressure that moves the member toward the axis of rotation.
Last dynamic pressure generation groove, The lubricating fluid and the lubricant retained in the radial bearing portion
It is continuous with the lubricating fluid held in the last bearing
And held by a lubricating fluid, Characterized by
Recording disk drive motor. 2. A stationary member and a relative member to the stationary member.
Is equipped with at least one rotatable recording disk
Rotating member and a rotor magnet fixed to the rotating member.
Together with the rotor magnet to generate a rotational driving force.
The stator disposed on the stationary member for
To support the radial load by rotating the rolling member
Of the rotating member and the radial bearing that generates the supporting force of
Support force to support the thrust load by rolling
The thrust bearing part, the radial bearing part and the
And a lubricating fluid held in the thrust bearing portion.
In recording disk drive motor,Communicating with a communication hole formed in the stationary member for communicating with the outside air
A pair of the radiators, which are formed on the upper and lower portions in the axial direction of the air interposition portion.
Al bearing part, The lubricating fluid retained in the radial bearing is
Axial direction that generates dynamic pressure that moves toward the strike bearing
Radially shaped herringbone that is unbalanced Al dynamic pressure
Generating groove, The lubricating fluid retained in the thrust bearing portion is
A spring that generates dynamic pressure that moves the member toward the axis of rotation.
Last dynamic pressure generation groove, The lubricating fluid and the lubricant retained in the radial bearing portion
It is continuous with the lubricating fluid held in the last bearing
And held by a lubricating fluid, Characterized by
Recording disk drive motor. 3. The recording disk drive motor according to claim 1, wherein the rotating member is biased in the axial direction by a magnetic force. 4. The rotating member includes a disc-shaped portion, a cylindrical portion extending in the axial direction from an outer peripheral portion of the disc-shaped portion, and a rotor magnet fixedly attached to an inner peripheral portion of the disc-shaped portion. The stationary member comprises a sleeve member having a hollow portion that is open at both ends in the axial direction and faces the shaft member with a minute gap in the radial direction. The recording disk drive motor according to claim 1, 2 or 3, wherein a lubricating fluid is held in the minute gap to configure the radial bearing portion. 5. An upper end portion of the sleeve member opposes a lower surface of the disk-shaped portion in the axial direction with a minute gap, and the lubricating fluid is held in the minute gap to form the thrust bearing portion. Claim 1 characterized in that
The recording disk drive motor described in 2, 3, or 4. 6. A thrust plate protruding outward in the radial direction is provided at one end of the shaft member, and the thrust plate is provided at one end of the sleeve member facing the outer peripheral surface of the thrust plate. Is formed, and one end of the hollow portion of the sleeve member is sealed by a cover member, and the step portion and the cover member are respectively in the axial direction with the thrust plate. The recording according to claim 1, 2, 3 or 4, wherein the thrust bearing portion is configured such that the lubricating fluid is opposed to each other through a minute gap and is held in at least a part of the minute gap. Disk drive motor. 7. The axially unbalanced herringbone-shaped dynamic pressure generating groove formed in the radial bearing portion is formed by combining a pair of spiral grooves in the axial direction, and is combined in the axial direction. Of the pair of spiral grooves formed, the axial dimension of the spiral groove located on the thrust bearing side is formed to be half or less than the axial dimension of the other spiral groove. The recording disk drive motor according to any one of claims 1 to 6. 8. The recording disk drive motor according to claim 1, a base plate on which the recording disk drive motor is mounted, and a recording disk mounted on the recording disk drive motor. And a recording head for reading and writing information.