JP2006283906A - Fluid dynamic pressure bearing motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To individually and separately circulate lubricating agent such as oil, etc., to a pair of radial fluid dynamic bearings and a pair of thrust fluid dynamic pressure bearings. <P>SOLUTION: A fluid dynamic pressure bearing motor 10A is provided with the pair of radial fluid dynamic pressure bearings 38 and 39 and the pair of thrust fluid dynamic pressure bearings 40 and 41. Each radial fluid dynamic pressure bearing of the pair of radial fluid dynamic pressure bearings 38 and 39, and each thrust fluid dynamic pressure bearing of the pair of radial fluid dynamic pressure bearings 40 and 41 are provided with long-sized communication passages 42 and 43 in the axial direction and first to third thrust communication passages 44, 47 and 48 in the radial direction as a communication means to circulate lubricating agent 33 without passing through the fluid dynamic pressure bearing other than each fluid dynamic pressure bearing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fluid dynamic bearing motor including a pair of radial fluid dynamic pressure bearing portions and a pair of thrust fluid dynamic pressure bearing portions when a hard disk or a polygon mirror is mounted and rotated at high speed. .

  Generally, a fluid dynamic pressure bearing is used as a bearing in a motor that is mounted with a hard disk or a polygon mirror and is driven to rotate at high speed.

  In general, the fluid dynamic pressure bearing described above is paired with an interval along the shaft direction corresponding to the longitudinal direction of the shaft between the cylindrical shaft (shaft) and the center hole of the annularly formed sleeve. And a pair of thrust fluid dynamic pressure bearing portions are provided between the end of the sleeve or the end of the shaft and the ring-shaped thrust plate, and a pair of radial fluid dynamic bearings are provided. The pressure bearing portion and the pair of thrust fluid dynamic pressure bearing portions are filled with a lubricant such as oil.

  In this type of fluid dynamic pressure bearing, when either the shaft side or the sleeve side is configured as the stator side and the other side is configured as the rotor side, a pair of radial fluid dynamic pressure bearing portions are arranged on the rotor side via a lubricant. And a pair of thrust fluid dynamic pressure bearing portions that support a thrust load on the rotor side via a lubricant, and a pair of radial fluid dynamic pressure bearing portions and a pair of thrust fluid dynamic pressure bearing portions Are called fluid dynamic pressure bearings.

At this time, there are a structural configuration in which the shaft (axis) side is fixed and the sleeve side is rotated, and a structural configuration in which the sleeve side is fixed and the shaft (shaft) side is rotated. When the rotating side is rotated at a high speed, the lubricant is moved by the dynamic pressure grooves formed in the pair of radial fluid dynamic pressure bearing portions and the pair of thrust fluid dynamic pressure bearing portions using a herringbone shape or the like. The pressure is generated and the rotation side is lifted with respect to the fixed side by this lubricant so that it can be rotated without contact and can be rotated with high accuracy at high speed. In order to circulate the lubricant when a dynamic pressure difference occurs, a long shaft direction communication passage (long in the shaft direction and having upper and lower ends communicating with a pair of thrust fluid dynamic pressure bearing portions ( Vertical communication passage) and A radial direction communication path (horizontal communication path) that is provided in a radial direction orthogonal to the shaft direction, with one end communicating with a pair of radial fluid dynamic bearings and the other end communicating with an intermediate portion of the shaft direction communication path. ) (See, for example, Patent Document 1 and Patent Document 2).
Japanese Patent No. 3558708 (page 3-4, FIG. 1) USP 4,254,961 (FIG. 2)

FIG. 31 is a longitudinal sectional view showing an example of a conventional fluid dynamic pressure bearing,
FIG. 32 is a longitudinal sectional view showing another example of a conventional fluid dynamic pressure bearing.

  First, the conventional fluid dynamic pressure bearing 100 shown in FIG. 31 is disclosed in the above-mentioned Patent Document 1 (Japanese Patent No. 3558708). explain.

  As shown in FIG. 31, in the conventional fluid dynamic pressure bearing 100 of the conventional example, the shaft main body portion 101a of the stationary shaft 101 formed in a columnar shape is inserted through an oil 103 into a center hole 102a of a sleeve 102 formed in an annular shape. By fitting, the rotating sleeve 102 is rotatably supported by the stationary shaft 101. At this time, the stationary shaft 101 has a shaft body portion 101a having a relatively large diameter, tapered portions 101b and 101c formed in a tapered shape above and below the shaft body portion 101a, and a small diameter above and below the tapered portions 101b and 101c. The shaft end portions 101d and 101e are connected to each other.

  In addition, a pair of cover members 104 and 105 functioning as ring-shaped thrust plates are fitted into a pair of circular recesses 102b and 102c formed in a circular recess on the upper and lower end sides of the rotating sleeve 102, and a pair of A pair of end plates 106 and 107 disposed above and below the cover members 104 and 105 are fixed to the upper and lower shaft end portions 101 d and 101 e of the stationary shaft 101.

  In addition, a pair of gaps are provided between the outer peripheral surface of the shaft main body portion 101a of the stationary shaft 101 and the inner peripheral surface of the central hole 102a of the rotary sleeve 102 in the shaft direction corresponding to the longitudinal direction of the shaft main body portion 101a. Radial fluid dynamic pressure bearing portions 108 and 109 are provided, and each of the pair of radial fluid dynamic pressure bearing portions 108 and 109 has herringbone-shaped radial fluid dynamic pressure grooves (not shown) on the outer periphery of the shaft main body portion 101a. It is formed on the inner peripheral surface of the center hole 102 a of the surface or the rotating sleeve 102.

  A pair of thrust fluid dynamic pressure bearing portions 110 and 111 are provided between the upper and lower ends of the shaft main body portion 101 a of the stationary shaft 101 and the lower and upper surfaces of the pair of cover members 104 and 105. The pair of thrust fluid dynamic pressure bearing portions 110 and 111 have herringbone-shaped thrust fluid dynamic pressure grooves (not shown) formed on the lower and upper surfaces of the pair of cover members 104 and 105.

  The pair of shaft direction communication passages (vertical communication passages) 112 and 113 are symmetrically provided on the left and right sides of the shaft main body 101a of the stationary shaft 101 so as to communicate with the pair of thrust fluid dynamic pressure bearing portions 110 and 111. It is suspended vertically.

  Further, one radial direction communication passage (lateral communication passage) 114 communicates at one end side between the pair of radial fluid dynamic pressure bearing portions 108 and 109 in the central portion of the shaft main body portion 101a of the stationary shaft 101 in the shaft direction. In addition, the other end side is provided horizontally so as to communicate with an intermediate portion between the pair of shaft direction communication passages 112 and 113.

  In the conventional fluid dynamic pressure bearing 100 configured as described above, when the rotary sleeve 102 rotates at a high speed, the pair of radial fluid dynamic pressure bearing portions 108 and 109 and the pair of thrust fluid dynamic pressure bearing portions 110 and 111 are changed to each other. A dynamic pressure is generated in the oil 103 by the formed radial fluid dynamic pressure grooves (not shown) and the thrust fluid dynamic pressure grooves (not shown). At this time, the radial fluid dynamic pressure grooves and the thrust fluids are generated. A dynamic pressure difference is generated in the oil 103 due to a manufacturing error of the dynamic pressure groove, and the oil 103 flows from a high pressure value toward a low value according to the dynamic pressure difference. 103 is refluxed in the direction of the arrow.

  That is, only the right side of the shaft 101 will be described. The oil 103 flows downward in the upper radial fluid dynamic pressure bearing portion 108 to the inner peripheral side of the radial communication path 114 formed at the central portion in the shaft direction. Later, it flows upward in the shaft direction communication passage 113 and flows back to the upper thrust fluid dynamic pressure bearing portion 110, and flows upward in the lower radial fluid dynamic pressure bearing portion 109 and then flows in the radial direction communication passage 114. Is directed to the inner peripheral side and then flows downward in the shaft direction communication passage 113 to return to the lower thrust fluid dynamic bearing portion 111.

  As a result, the life of the pair of radial fluid dynamic pressure bearing portions 108 and 109 and the pair of thrust fluid dynamic pressure bearing portions 110 and 111 is prolonged without the oil 103 being partially deteriorated, and can be used stably over a long period of time. The effect is disclosed.

  Next, another conventional fluid dynamic pressure bearing 200 shown in FIG. 32 is disclosed in Patent Document 2 (USP 4,254,961) described above. Will be briefly described.

  In the conventional fluid dynamic pressure bearing 200 shown in FIG. 32, 201 is a cylindrical shaft, 202 is an annular sleeve, 203 is an outer peripheral surface 201a of the shaft 201 and a central portion of the sleeve 202. The oil is interposed between the central hole 202a formed through the hole, 204 is a ring-shaped hub fitted in the central portion of the outer peripheral surface 202b of the sleeve 202, and 205 and 206 are the outer periphery of the sleeve 202. A pair of permanent magnets fitted on the top and bottom of the surface 202b and provided on the top and bottom of the hub 204, and 207 and 208 are a pair of first washers provided on the top and bottom of the pair of permanent magnets 205 and 206 in a ring shape. .

  Reference numerals 209 and 210 denote a pair of ring-shaped thrust plates fixed to the top and bottom of the shaft 201 in a pair of circular recesses 202c and 202d formed in a circular concave shape on the upper and lower end sides of the sleeve 202, 211 and 212, respectively. Are a pair of second washers fixed to the shaft 201 above and below the pair of ring-shaped thrust plates 209 and 210, and 213 and 214 are screwed into the pair of first washers 207 and 208, respectively. It is a pair of plugs that cover the pair of second washers 211 and 212 while facing the ends.

  A pair of radial fluid dynamic pressure bearing portions 215 is provided between the outer peripheral surface 201 a of the shaft 201 and the inner peripheral surface of the center hole 102 a of the sleeve 202 with a gap in the shaft direction corresponding to the longitudinal direction of the shaft 201. 216 is provided.

  A pair of thrust fluid dynamic pressure bearing portions 217 and 218 are provided between the end portions of the circular recesses 201c and 201d of the sleeve 202 and the lower and upper surfaces of the pair of ring-shaped thrust plates 209 and 210, respectively. Yes.

  Further, on the left and right sides of the sleeve 202, a pair of shaft direction communication paths (vertical communication paths) 219, 220 are vertically elongated so as to communicate with the pair of thrust fluid dynamic pressure bearing portions 217, 218. It is.

  Further, a radial direction communication passage (lateral communication passage) 221 communicates at one end side between the pair of radial fluid dynamic pressure bearing portions 215 and 216 at the central portion in the shaft direction in the sleeve 202 and a pair of shafts at the other end side. It is laterally arranged so as to communicate with an intermediate portion of the direction communication passages 219 and 220.

  In another conventional fluid dynamic bearing 200 configured as described above, when the shaft 201 is set on the stator side (fixed side) and the sleeve 202 is set on the rotor side (rotation side), the sleeve 202 side is When rotating at high speed, dynamic pressure is generated in the oil 203 by the pair of radial fluid dynamic pressure bearing portions 215, 216 and the pair of thrust fluid dynamic pressure bearing portions 217, 218. Since a dynamic pressure difference is generated in the oil 203 due to the manufacturing error, the oil 203 can be recirculated through the pair of shaft direction communication paths 219 and 220 and the radial direction communication path 221 as in the case of FIG. It is obtained.

  By the way, in the conventional fluid dynamic pressure bearing 100 shown in FIG. 31, a pair of radial fluid dynamic pressure bearing portions 108 and 109 and a pair of thrust fluid dynamic pressure bearing portions 110 and 111 are used to recirculate oil 103. Shaft direction communication passages (vertical communication passages) 112 and 113 and one radial direction communication passage (horizontal communication passage) 114 are provided in the shaft 101, and the conventional fluid dynamic pressure shown in FIG. In the bearing 200, a pair of radial fluid dynamic pressure bearing portions 215, 216 and a pair of thrust fluid dynamic pressure bearing portions 217, 218 are provided with a pair of shaft direction communication passages (vertical communication passages) 219, 220 and the like. Although one radial direction communication passage (lateral communication passage) 221 is provided in the sleeve 202, in any of the fluid dynamic pressure bearings 100 and 200, Even if the processing accuracy of each radial fluid dynamic pressure groove (not shown) formed in the pair of radial fluid dynamic pressure bearings is increased, there is a slight difference in processing accuracy such as cylindricity and groove shape. A slight difference occurs in the pressure value, and also occurs in each thrust fluid dynamic pressure groove (not shown) formed in the pair of thrust fluid dynamic pressure bearings due to differences in processing accuracy such as perpendicularity and groove shape. A slight difference occurs in the dynamic pressure value.

  Accordingly, as described above, the communication path of the upper radial fluid dynamic pressure bearing portion includes the radial direction communication path (lateral communication path) formed between the pair of radial fluid dynamic pressure bearing portions and the shaft direction communication path. (Longitudinal communication path) and return to the upper radial fluid dynamic pressure bearing part via the upper thrust fluid dynamic pressure bearing part, while the communication path of the lower radial fluid dynamic pressure bearing part is a pair of radial fluids The lower radial fluid dynamic pressure passes through the lower thrust fluid dynamic bearing through the radial communication passage (horizontal communication passage) and the shaft communication passage (vertical communication passage) formed between the dynamic pressure bearing portions. Return to the bearing.

  Therefore, the flow of oil due to the difference in the dynamic pressure of the oil generated in the upper or lower radial fluid dynamic pressure bearing portion is problematic because it affects the upper or lower thrust fluid dynamic pressure bearing portion.

  In any case, in a bearing using a fluid dynamic pressure bearing, since there is a difference in the generation of each dynamic pressure, it is necessary to balance each dynamic pressure generation section. In this case, a pair of radial fluid dynamic pressure bearing sections In addition, a fluid dynamic bearing motor including a communication passage means capable of circulating a lubricant such as oil individually with respect to a pair of thrust fluid dynamic pressure bearing portions is desired.

The present invention has been made in view of the above problems, and the invention according to claim 1 includes a shaft that is pivotally attached to a central hole of a sleeve formed in an annular shape,
Electromagnetic driving means for rotating the rotor side relative to the stator side when either the shaft side or the sleeve side is configured as a stator side and the other side is configured as a rotor side;
A pair of radial fluid dynamic pressure bearing portions that are provided at intervals in the shaft direction corresponding to the longitudinal direction of the shaft and that support a radial load on the rotor side via a lubricant;
A pair of thrust fluid dynamic pressure bearings provided on one end side in the shaft direction or on each end side in the shaft direction and supporting a thrust load on the rotor side via the lubricant In a fluid dynamic pressure bearing motor comprising:
The radial fluid dynamic pressure bearing portions of the pair of radial fluid dynamic pressure bearing portions and the thrust fluid dynamic pressure bearing portions of the pair of thrust fluid dynamic pressure bearing portions are fluid dynamic pressures other than the fluid dynamic pressure bearing portions themselves. The fluid dynamic bearing motor is characterized in that communication passage means for circulating the lubricant without passing through the bearing portion is provided.

The invention according to claim 2 is the fluid dynamic bearing motor according to claim 1,
The radial fluid dynamic pressure grooves of the pair of radial fluid dynamic pressure bearing portions are provided on either the inner peripheral surface of the center hole of the sleeve or the outer peripheral surface of the shaft, and the pair of thrust fluid dynamic pressure bearing portions Each thrust fluid dynamic pressure groove is opposed to the end portion in the shaft direction of the sleeve or the end portion in the shaft direction of the ring-shaped thrust plate opposed to the end portion in the shaft direction of the sleeve or the large diameter portion formed in the shaft. A fluid dynamic pressure bearing motor is provided on any one of the ring-shaped thrust plates.

Furthermore, the invention according to claim 3 is the fluid dynamic bearing motor according to claim 1 or 2,
The communication passage means is provided in a radial direction at an intermediate portion in the shaft direction, and one end side communicates between the pair of radial fluid dynamic pressure bearing portions. And a first radial direction communication path whose other end side communicates with an intermediate portion of the shaft direction communication path, and one end side is provided on the pair of radial fluid dynamic pressure bearing parts side in the radial direction above and below the shaft direction. And communicated with the upper and lower parts positioned above and below the pair of radial fluid dynamic pressure bearing parts, and each end side communicated with the upper and lower parts of the shaft direction communication path, and between each one end side and each other side The fluid dynamic pressure bearing motor has at least second and third radial direction communication passages communicating with the thrust fluid dynamic pressure bearing portions.

  The fluid dynamic pressure bearing motor according to the present invention includes a pair of radial fluid dynamic pressure bearing portions and a pair of thrust fluid dynamic pressure bearing portions when a hard disk or a polygon mirror is mounted and rotated at high speed. In particular, each radial fluid dynamic pressure bearing portion of the pair of radial fluid dynamic pressure bearing portions and each thrust fluid dynamic pressure bearing portion of the pair of thrust fluid dynamic pressure bearing portions are other than each fluid dynamic pressure bearing portion itself. Since the communication passage means for circulating the lubricant without using the fluid dynamic pressure bearing portion is provided, each communication passage means functions to cancel the imbalance of the dynamic pressure pump balance. The flow of oil due to the difference in the dynamic pressure of the oil generated in the radial fluid dynamic pressure bearing does not affect the upper or lower thrust fluid dynamic pressure bearing, and the lubricant can be returned in an appropriate amount. Runode, can be improved in performance and reliability of the fluid dynamic bearing motor.

  Hereinafter, an embodiment of a fluid dynamic bearing motor according to the present invention will be described in detail in the order of Embodiment 1 to Embodiment 12 with reference to FIGS.

  The fluid dynamic bearing motor according to the present invention is configured to be mounted on a hard disk or a polygon mirror so as to be driven to rotate at a high speed. In particular, a pair of radials described in Examples 1 to 12 described below. Any structure may be used as long as it includes any one of the fluid dynamic pressure bearings including the fluid dynamic pressure bearing portion and the pair of thrust fluid dynamic pressure bearing portions, in particular, the pair of radial fluid dynamic pressure bearing portions. Each radial fluid dynamic pressure bearing portion and each thrust fluid dynamic pressure bearing portion of the pair of thrust fluid dynamic pressure bearing portions circulate the lubricant without passing through any fluid dynamic pressure bearing portion other than each fluid dynamic pressure bearing portion itself. Each of the communication path means is provided.

  In the following, an example will be described in which a hard disk is attached to the fluid dynamic bearing motor according to the present invention, and the hard disk is rotationally driven at high speed with high accuracy in a magnetic disk drive (HDD).

  At this time, in the fluid dynamic pressure bearing motors of Examples 1 to 12 according to the present invention, when the structure form in which the shaft (shaft) side is fixed and the sleeve side is rotated is adopted, the structure form of the fluid dynamic pressure bearing Are different for each embodiment, and will be described in detail with respect to the first embodiment, but only the differences between the second embodiment and the second embodiment with respect to the first embodiment and / or other embodiments will be described. To do.

  In the fluid dynamic bearing motor according to the present invention, it is possible to adopt a structure in which the sleeve side is fixed and the shaft (shaft) side is rotated, but the illustration is omitted here.

1A is a longitudinal sectional view showing a fluid dynamic bearing motor of Example 1 according to the present invention, and FIG.
FIG. 2 is a longitudinal sectional view showing, in an enlarged manner, a fluid dynamic pressure bearing, which is a main part of Example 1, in the fluid dynamic pressure bearing motor of Example 1 according to the present invention,
3 (A) to 3 (E) are enlarged perspective views showing examples in which the shape of the ring-shaped thrust plate is changed in the fluid dynamic pressure bearing shown in FIG.
4A to 4C are cross-sectional views showing examples in which the shape of the shaft direction communication path is changed in the fluid dynamic pressure bearing shown in FIG. 2 along the roll line of FIG. is there.

  As shown in FIG. 1, the fluid dynamic bearing motor 10A according to the first embodiment of the present invention is installed in a magnetic disk drive (not shown) and is mounted with at least one hard disk HD. The fluid dynamic pressure bearing 30A including a pair of radial fluid dynamic pressure bearing portions 38 and 39 and a pair of thrust fluid dynamic pressure bearing portions 40 and 41 constituting the main part of Example 1 is configured to be able to rotate at high speed with high accuracy. ing.

  The fluid dynamic bearing motor 10A according to the first embodiment of the present invention described above is roughly composed of a stator S that is fixedly installed on the shaft (shaft) side and a rotor R that is rotationally driven on the sleeve side.

  First, on the stator S side, a motor base 11 serving as a base is cut into a circular concave cup shape using an aluminum die-cast material, and a cylindrical shaft 12 is formed at the central portion of the bottom surface 11a of the motor base 11. It is planted by press-fitting vertically upward. At this time, the shaft 12 is usually made of martensite, ferrite, or austenitic stainless steel, but the outer peripheral surface 12a has a surface coating such as electroless nickel plating for the purpose of improving wear resistance. The film is attached with a thickness of about 50 μm.

  A ring-shaped recess 11b is formed concentrically with the shaft 12 and has a large diameter above the bottom surface 11a of the motor base 11, and a plurality of stator cores 13 using silicon steel plates are laminated in the ring-shaped recess 11b. The stator core 13 is coated with an insulating coating by electrodeposition coating, powder coating, or the like, and the coil 14 is wound in, for example, three phases.

  And the winding terminal 14a of the coil 14 is soldered to the flexible printed wiring board 15 attached to the back surface of the bottom surface 11a of the motor base 11 through the through hole 11a1 formed in the bottom surface 11a of the motor base 11, and the connector 16 is connected. To a drive circuit of a magnetic disk drive device (not shown).

  Next, on the rotor R side, the hub 17 is cut into a substantially cylindrical shape using an aluminum material, and the flange portion 17b is formed below the cylindrical outer peripheral surface 17a to have a larger diameter than the outer peripheral surface 17a. At least one hard disk HD is mounted on the flange portion 17b. Here, two hard disks HD are mounted on the flange portion 17b via spacers 18.

Further, a central hole 17c is formed in the central portion of the hub 17 so as to penetrate the large diameter, and an annular outer sleeve constituting a part of a fluid dynamic pressure bearing 30A described later in the central hole 17c. 31 and the outer peripheral surface 32a of the annular inner sleeve 32 is inserted into the center hole 31b serving as the inner peripheral surface of the outer sleeve 31, so that both the sleeves 31 and 32 are connected to the hub 17. It is integrated. In this state, the outer peripheral surface 12a of the shaft 12 is axially attached via a lubricant 33 such as oil in the center hole 32b which is the inner peripheral surface of the inner sleeve 32. Also, the flange portion 17b formed below the hub 17 A circular concave portion 17d is formed on the back surface of the circular concave portion with a large diameter, and a rotor yoke 19 formed in a ring shape by applying nickel plating to an iron material on the inner peripheral surface of the circular concave portion 17d is bonded with an adhesive. Furthermore, the magnet 20 with electrodeposition coating is adhered to the inner peripheral surface of the rotor yoke 19 with an adhesive.

  The flange portion 17b formed below the hub 17 enters the ring-shaped recess portion 11b of the motor base 11 described above with a gap in the radial direction from above, and the inner periphery of the flange portion 17b of the hub 17 The rotor yoke 19 and the magnet 20 bonded to the surface are opposed to the stator core 13 and the coil 14 fixed in the ring-shaped recess 11b of the motor base 11. At this time, the rotor yoke 19 and the magnet 20 bonded to the inner peripheral surface of the flange portion 17b of the hub 17 and the stator core 13 and the coil 14 fixed in the ring-shaped recess 11b of the motor base 11 are connected to the rotor S with respect to the stator S side. Electromagnetic drive means for rotating the side.

  When the motor 10A is assembled, a pair of ring-shaped thrust plates 34 and 35 constituting a part of a fluid dynamic pressure bearing 30A described later are in contact with the upper and lower ends in the shaft direction in the inner sleeve 32, and A pair of ring-shaped counter plates 36 and 37 that are fixed to the upper and lower parts of the shaft 12 by press-fitting or the like and constitute a part of a fluid dynamic pressure bearing 30A described later are formed at upper and lower ends of the outer sleeve 31, respectively. The pair of ring-shaped counter plates 36 and 37 are fitted in the circular recesses 31 c and 31 d and are slidably contacted above and below the pair of ring-shaped thrust plates 34 and 35 fixed to the shaft 12.

  At this time, the lubricant 33 is provided between the outer peripheral surface 12a of the shaft 12 and the center hole 32b of the inner sleeve 32, and between the upper and lower ends of the inner sleeve 32 and the pair of ring-shaped thrust plates 34, 35. However, by forming the tapered portions 12b and 12c at the upper and lower portions of the shaft 12 facing the inner peripheral surfaces of the pair of upper and lower ring-shaped counter plates 36 and 37, for example, only the lower portion of the shaft 12 is formed. 1B will be described with reference to the enlarged view of the portion A shown in FIG. 1B. A part of the gap is formed between the inner peripheral surface of the center hole 37b of the lower ring-shaped counter plate 37 and the tapered portion 12c of the shaft 12. Since it narrows, the capillary 33 prevents the lubricant 33 from leaking downward. Similarly, the inner peripheral surface of the center hole 36b (FIG. 2) of the upper ring-shaped counter plate 36 is prevented. Lubricant 33 is prevented from leaking upward between the tapered portion 12b of the shaft 12.

  The screw hole 12d formed in the upper end portion of the shaft 12 is formed to fix the motor 10A via a top plate (not shown), and the shaft 12 is coated with a surface coating such as electroless nickel plating. When applied, the female thread tap may be cut after plating.

  After the motor 10A is assembled as described above, when each phase of the coil 14 attached to the motor base 11 on the stator S side is energized, the rotor yoke 19 and the magnet 20 attached to the hub 17 on the coil 14 and rotor R side are connected. The hard disk HD attached to the hub 17 is rotationally driven at high speed and with high accuracy by a fluid dynamic pressure bearing 30A described later, and the rotational speed at this time is 7200 r / min.

  Here, the fluid dynamic pressure bearing 30A, which is a main part of the first embodiment, will be described in detail with reference to FIG. First, as shown in an enlarged view in FIG. 2, the fluid dynamic pressure bearing 30 </ b> A, which is the main part of the first embodiment, is between the outer peripheral surface 12 a of the shaft 12 and the inner peripheral surface of the center hole 32 b of the inner sleeve 32. A pair of radial fluid dynamic pressure bearing portions 38, 39 provided on the one side with predetermined axial lengths L1, L2 at intervals along the shaft direction corresponding to the longitudinal direction of the shaft 12 respectively. A pair of thrust fluid dynamic pressure bearings provided on either side between each radial fluid dynamic pressure groove, the upper and lower ends of the inner sleeve 32, and the lower and upper surfaces of the pair of ring-shaped thrust plates 34A, 35A A long shaft provided at least one or more along the shaft direction on either side between the thrust fluid dynamic pressure grooves of the portions 40 and 41 and the outer sleeve 31 and the inner sleeve 32 The communication passages (vertical communication passages) 42, 43 and the inner sleeve 32 are provided in a radial direction at an intermediate portion in the shaft direction, and one end side communicates between the pair of radial fluid dynamic bearing portions 38, 39 and the other end side A radial direction communication path (horizontal communication path) 44 communicating with an intermediate portion of the shaft direction communication paths 42 and 43 and a pair of ring-shaped thrust plates 34A and 35A are provided in the radial direction, and each one end side is connected to each center hole 34b, Positioned above and below the pair of radial fluid dynamic pressure bearing portions 38, 39 on the side of the pair of radial fluid dynamic pressure bearing portions 38, 39 via the bottomed recesses 34c, 35c formed on the inner peripheral surface side of 35b. A pair of radial communication paths (lateral communication paths) 45 that communicate with the upper and lower parts of the shaft and that communicate with the upper and lower parts of the shaft direction communication paths 42 and 43 through the outer peripheral gaps 47 and 48 on the other end side. It is composed of a 46.

  More specifically, the fluid dynamic pressure bearing 30A, which is a main part of the first embodiment, is unitized by integrally fitting the inner sleeve 32 to the outer sleeve 31 by press fitting, caulking, bonding, welding, or the like. And can be assembled easily.

  Although illustration is omitted here, it is also possible to form the inner sleeve as a simple sleeve without providing the outer sleeve, and to fit the outer peripheral surface of the sleeve into the center hole (17c) of the hub (17). However, if the outer sleeve is provided, the fluid dynamic pressure bearing 30A can be unitized and assembled with high accuracy.

  Accordingly, the outer sleeve 31 is formed in an annular shape using an aluminum material that is the same material as the hub 17. At this time, the outer sleeve 31 penetrates between the circular recesses 31c and 31d formed in the upper and lower ends concentrically with the outer peripheral surface 31a fitted into the center hole 17c of the hub 17. Is formed.

  In addition, the inner sleeve 32 is formed of the center hole 31b of the outer sleeve 31 using brass (C3602) or the like having good workability with respect to each of the radial fluid dynamic pressure grooves of a pair of radial fluid dynamic pressure bearing portions 38 and 39 described below. It is formed in an annular shape with a length shorter than the length. At this time, the inner sleeve 32 is formed such that the central hole 32b is formed concentrically with the outer peripheral surface 32a fitted into the central hole 31b of the outer sleeve 31, and is formed on the inner peripheral surface of the central hole 32a. A pair of radial fluid dynamic pressure bearing portions 38, 39 are formed with predetermined axial lengths L1, L2 at intervals while being along the shaft 12.

  Here, the pair of radial fluid dynamic pressure bearing portions 38 and 39 formed at intervals on the inner peripheral surface of the center hole 32a of the inner sleeve 32 is a herringbone or the like in order to generate dynamic pressure in the radial direction. Each radial fluid dynamic pressure groove is formed by a ray-lay step or the like, and in the first embodiment, for example, a herringbone that is bent in a “letter shape” is formed. And a pair of radial fluid dynamic-pressure bearing parts 38 and 39 can rotate the rotor R side non-contact with respect to a radial direction by supporting the radial load by the side of the rotor R via the lubricant 33. .

  At this time, the pair of radial fluid dynamic pressure bearing portions 38 and 39 may be formed on the outer peripheral surface 12a of the shaft 12. However, it is preferable that the rotor R is formed on the inner peripheral surface of the center hole 32a of the inner sleeve 32 after assembly. The rotation accuracy on the side becomes good.

  Accordingly, the pair of radial fluid dynamic pressure bearing portions 38, 39 may be provided on either the inner peripheral surface of the center hole 32 a of the inner sleeve 32 or the outer peripheral surface 12 a of the shaft 12.

  For the convenience of illustration, the pair of radial fluid dynamic pressure bearing portions 38, 39 provided on the inner peripheral surface of the center hole 32a of the inner sleeve 32 is different from the inner peripheral surface of the center hole 32a of the inner sleeve 32. The herringbone patterns bent in the shape of "" on the outer peripheral surface 12a of 12 are shown in the following figures.

  The pair of ring-shaped thrust plates 34 and 35 that are in contact with the upper and lower ends in the shaft direction in the inner sleeve 32 and are fitted to the upper and lower sides of the shaft 12 are made of nickel-plated copper alloy material or stainless steel material. In the first embodiment, a pair of ring thrust plates 34A and 35A shown in FIG. 3A described later are applied.

  The pair of ring-shaped thrust plates 34 and 35 are formed so as to be concentric with the outer peripheral surfaces 34a and 35a through the center holes 34b and 35b, and the outer peripheral surface 12a of the shaft 12 is inserted into the respective center holes 34b and 35b. The upper and lower parts are fitted.

  In addition, the pair of ring-shaped thrust plates 34 and 35 are provided with a pair of thrust fluid dynamic pressure bearing portions 40 and 41 on the surface side facing the upper and lower ends of the inner sleeve 32. Each thrust fluid dynamic pressure groove is formed in the pressure bearing portions 40 and 41 by a herringbone or a Rayleigh step in order to generate dynamic pressure in the thrust direction. In the first embodiment, each thrust fluid dynamic pressure groove is illustrated in FIG. 6 (A) and 6 (B) are enlarged by etching or stamping with a herringbone bent in a “character shape”. The pair of thrust fluid dynamic pressure bearing portions 40 and 41 can rotate the rotor R side in a non-contact manner with respect to the shaft direction by supporting the thrust load on the rotor R side via the lubricant 33. .

  In the first embodiment, as described above, the pair of thrust fluid dynamic pressure bearing portions 40 and 41 is provided on the surface side facing the upper and lower ends of the inner sleeve 32 in the pair of ring-shaped thrust plates 34 and 35. Although provided, in each embodiment described later, a pair of thrust fluid dynamic pressure bearing portions 40, 41 may be provided on the upper and lower surfaces (both surfaces) of the pair of ring-shaped thrust plates 34, 35 as needed.

  At this time, the pair of thrust fluid dynamic pressure bearing portions 40 and 41 may be provided at the upper and lower ends of the inner sleeve 32, but the workability is better when the pair is provided on the pair of ring-shaped thrust plates 34 and 35. It is.

  Accordingly, the pair of thrust fluid dynamic pressure bearing portions 40 and 41 may be provided at either one of the pair of ring-shaped thrust plates 34 and 35 or the upper and lower end portions of the inner sleeve 32.

  Further, as shown in an enlarged view of FIG. 3, the pair of ring-shaped thrust plates 34 and 35 is applied with any one of the shapes (A) to (E) according to each embodiment. In the first embodiment, as described above, the pair of ring-shaped thrust plates 34A and 34B formed in the shape shown in FIG.

  Further, when the pair of ring-shaped thrust plates 34 and 35 are fixed to the shaft 12 as in the first embodiment and the second to eighth embodiments described later, the diameters of the outer peripheral surfaces 34a and 35a are the inner sleeve 32 ( 2) is formed so as to be slightly smaller than the inner diameter of the center hole 32b, and the inner diameters of the center holes 34b and 35b can be fitted to the shaft 12, while as in Examples 9 to 12 described later. When the inner sleeve 32 is fixed in the center hole 32b, the diameters of the outer peripheral surfaces 34a and 35a are formed so as to fit into the center hole 32b of the inner sleeve 32, and the inner diameters of the center holes 34b and 35b are set to the shaft 12. The diameter is slightly larger than the diameter.

  Here, as shown in FIG. 3A, in the pair of ring-shaped thrust plates 34A, 35A, a pair of radial communication passages (horizontal communication passages) 45, 46 penetrates symmetrically 180 degrees in the radial direction. The bottomed recesses 34c and 35c are formed on the inner peripheral surface side of the center holes 34b and 35b on the side facing the upper and lower ends of the inner sleeve 32 (FIG. 2). It is formed in a concave shape symmetrical to 180 degrees so as to communicate with the radial direction communication passages 45 and 46 (FIG. 2).

  At this time, the pair of radial communication paths (lateral communication paths) 45 and 46 formed in the pair of ring-shaped thrust plates 34A and 35A has a pair of ends on the side of the center holes 34b and 35b as shown in FIG. It communicates with the pair of radial dynamic pressure bearing portions 38 and 39 via bottomed recesses 34c and 35c formed on the inner peripheral surface side of the ring-shaped thrust plates 34A and 35A, and the other end on the outer peripheral surface 34a and 35a side. 2 communicates with the shaft direction communication passages 42 and 43 through the outer circumferential gaps 47 and 48 of the pair of ring-shaped thrust plates 34A and 35A, as shown in FIG. Is set to about 0.3 mm square in cross-sectional area.

  Although not shown here, a plurality of radial communication paths are formed radially from the center holes 34b, 35b side of the pair of ring-shaped thrust plates 34A, 35A toward the outer peripheral surfaces 34a, 35a. Also good.

  Further, as shown in FIG. 3B, the pair of ring-shaped thrust plates 34B and 35B has a pair of radial communication passages (lateral communication passages) 45 and 46 penetrating symmetrically by 180 degrees in the radial direction. In addition, through recesses 34d and 35d are formed in a concave shape symmetrically by 180 degrees on the inner peripheral surface side of the center holes 34b and 35b.

  Further, as shown in FIG. 3C, in the pair of ring-shaped thrust plates 34C and 35C, through-recesses 34e and 35e are formed in a concave shape symmetrically by 180 degrees on the inner peripheral surface side of the center holes 34b and 35b. .

  Further, as shown in FIG. 3D, the pair of ring-shaped thrust plates 34D, 35D has a pair of radial communication paths (lateral communication paths) 45, 46 penetrating symmetrically by 180 degrees in the radial direction. The bottomed recesses 34f and 35f are formed in a concave shape symmetrically by 180 degrees on the outer peripheral surfaces 34a and 35a side.

  Further, as shown in FIG. 3 (E), the pair of ring-shaped thrust plates 34E and 35E are concentric with the outer peripheral surfaces 34a and 35a, and the center holes 34b and 35b are penetrated so as to be simply ring-shaped. It is only formed.

  Returning to FIG. 2 again, the pair of ring-shaped counter plates 36 and 37 fitted to the circular recesses 31c and 31d formed at the upper and lower ends of the outer sleeve 31 are made of nickel-plated copper alloy material or stainless steel material. Are formed concentrically with the outer peripheral surfaces 36a and 37a so as to penetrate through the center holes 36b and 37b to form a ring-shaped flat plate, and the center holes 36b and 37b are provided at the upper and lower ends of the shaft 12, respectively. The taper portions 12b and 12c are formed to face each other with a slight gap.

  Further, at least one or more shaft direction communication paths (vertical communication paths) are provided between the outer sleeve 31 and the inner sleeve 32 so as to extend in the shaft direction. A pair of shaft direction communication paths (vertical communication paths) 42 and 43 are provided on the left and right sides that are 180 degrees symmetrical about the shaft 12. The upper and lower end portions of the pair of shaft direction communication passages 42 and 43 communicate with the pair of thrust fluid dynamic pressure bearing portions 40 and 41 and the outer peripheral clearance 47 of the pair of ring-shaped thrust plates 34A and 35A. , 48 communicate with radial communication passages 45, 46 provided in the ring-shaped thrust plates 34A, 35A.

  At this time, the pair of shaft direction communication passages 42 and 43 adopts one of the shapes shown in FIGS.

  That is, in the example shown in FIG. 4A, a pair of shaft direction communication passages 42 and 43 are formed by processing a semicircular concave groove on the inner peripheral surface side of the center hole 31b of the outer sleeve 31 symmetrically by 180 degrees. After the formation, the outer peripheral surface 32a of the inner sleeve 32 is fitted into the center hole 31b of the outer sleeve 31 and assembled.

  In the example shown in FIG. 4B, a D-cut is applied to the outer peripheral surface 32a of the inner sleeve 32 symmetrically by 180 degrees so that the center hole 31b of the outer sleeve 31 and the D-cut portion of the outer peripheral surface 32a of the inner sleeve 32 A pair of shaft direction communication passages 42 and 43 are formed between them.

  Further, in the example shown in FIG. 4C, after forming a pair of shaft direction communication paths 42 and 43 by processing a semicircular concave groove 180 degrees symmetrically on the outer peripheral surface 32a side of the inner sleeve 32, The outer peripheral surface 32a of the inner sleeve 32 is fitted into the center hole 31b of the outer sleeve 31 and assembled.

  In the first embodiment, as shown in FIG. 2, the pair of shaft direction communication passages 42 and 43 are formed in a straight line shape perpendicular to the shaft direction. The directional communication passages (42, 43) may be formed in a spiral shape (spiral shape) along the inner peripheral surface of the center hole 31 b of the outer sleeve 31 or the outer peripheral surface 31 a of the inner sleeve 32.

  Therefore, the shape and processing of at least one shaft direction communication path (42, 43) can be freely selected on the outer sleeve 31 side or the inner sleeve 32 side.

  Furthermore, at least one radial communication path (lateral communication path) 44 is provided in the radial direction in the intermediate portion of the inner sleeve 32 in the shaft direction. A plurality of radials may be provided at this position. The above-described radial communication passage 44 has one end communicating with a pair of radial fluid dynamic pressure bearing portions 38 and 39 and the other end communicating with at least one intermediate portion of one or more shaft communication passages (42, 43). is doing.

  Next, the operation of the fluid dynamic pressure bearing 30A, which is the main part of the first embodiment configured as described above, will be described with reference to FIGS.

FIGS. 5A to 5G are diagrams schematically illustrating the operation of a pair of radial fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are essential portions of the first embodiment.
FIGS. 6A to 6F are diagrams schematically illustrating the operation of a pair of thrust fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are the main portions of the first embodiment.

  First, as shown in FIG. 5A, a pair of radial fluid dynamics provided on either side between the shaft 12 and the inner sleeve 32 in the fluid dynamic pressure bearing 30 </ b> A that is a main part of the first embodiment. As described above, the pressure bearing portions 38 and 39 are formed with herringbones bent in, for example, a “shape” as each radial fluid dynamic pressure groove, and each radial fluid is rotated when the rotor R (FIG. 1) is rotated. Although the dynamic pressure value generated in the lubricant 33 (FIGS. 1 and 2) by the dynamic pressure groove is set to be the same in design, the cylinder is not affected even if the processing accuracy of each radial fluid dynamic pressure groove is increased. Since there is a slight difference in processing accuracy such as degree and groove shape, a slight difference (dynamic pressure difference) occurs in the generated dynamic pressure value, and the lubricant 33 is in a direction from a higher dynamic pressure value to a lower direction according to the dynamic pressure difference. To compensate for the lack of lubricant 33 By circulating the lubricant 33, it is necessary to feed back the appropriate amount of the lubricant 33.

  Along with the above, the dynamic pressure value generated at the upper bent portion 38a of the herringbone bent in a “letter shape” in the upper radial fluid dynamic pressure bearing portion 38 is indicated by a, and the dynamic pressure value generated at the lower bent portion 38b. Is indicated by b, and the dynamic pressure value generated in the entire upper radial fluid dynamic pressure bearing portion 38 is indicated by A.

Similarly, the dynamic pressure value generated at the upper bent portion 39c of the herringbone bent in a “character shape” in the lower radial fluid dynamic pressure bearing portion 39 is indicated by c, and the dynamic pressure value generated at the lower bent portion 39d is indicated by c. In addition to d, B represents a dynamic pressure value generated in the entire lower radial fluid dynamic bearing portion 39.

  Here, when the inner sleeve 32 side rotates, as shown in FIG. 5B, in the above-described dynamic pressure values a to d, the generation of the dynamic pressure values is a> b and c = d. In this case, the lubricant 33 exiting through the upper radial fluid dynamic pressure bearing 38 is directed to the outer peripheral side through the radial communication passage 44 provided at the intermediate portion in the inner sleeve 32 as indicated by an arrow. Thereafter, the gas flows upward in a long shaft direction communication path 43 provided between the outer sleeve 31 and the inner sleeve 32 and the outer peripheral clearance 47 of the upper ring-shaped thrust plate 34A, and further, the upper ring After flowing in the radial direction communication passage 45 provided in the inner thrust plate 34A toward the inner peripheral side, it flows downward through a bottomed recess 34c formed on the inner peripheral surface side of the upper ring-shaped thrust plate 34A. Circulated back to the upper side of the radial fluid dynamic pressure bearing portion 38. In this case, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and a pair of upper and lower ring-shaped thrust plates 34A, It circulates without passing through a pair of thrust fluid dynamic pressure bearing portions 40, 41 formed in 35A.

  Further, as shown in FIG. 5C, when the generation of each dynamic pressure value is a <b and c = d, the lubricant that has left the upper side through the radial fluid dynamic bearing 38 is provided. Reference numeral 33 denotes an upper ring shape after flowing upward through a bottomed recess 34c formed on the inner peripheral surface side of the upper ring-shaped thrust plate 34A with the direction of the arrow reversed to that of FIG. The radial communication passage 45 provided in the thrust plate 34A is directed to the outer peripheral side, and then flows downward through the outer circumferential clearance 47 of the upper ring-shaped thrust plate 34A and the long shaft direction communication passage 43. Then, it circulates so as to flow toward the inner peripheral side through the radial direction communication passage 44 provided at the intermediate portion in the inner sleeve 32 and return to the upper radial fluid dynamic pressure bearing portion 38. In this case as well, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and a pair of upper and lower ring thrust plates 34A. , 35A circulate without passing through the pair of thrust fluid dynamic bearing portions 40, 41.

  Further, as shown in FIG. 5D, when the generation of each dynamic pressure value is c> d and a = b, the lubrication that exits here through the lower radial fluid dynamic bearing portion 39. The agent 33 is provided in the lower ring-shaped thrust plate 35A after flowing downward through the bottomed recess 35c formed on the inner peripheral surface side of the lower ring-shaped thrust plate 35A as indicated by an arrow. The radial communication path 46 is directed to the outer peripheral side, and then flows upward through the outer circumferential gap 48 of the lower ring-shaped thrust plate 35A and the long shaft direction communication path 43, and further inside the inner sleeve 32. It circulates so as to flow in the radial direction communication passage 44 provided in the intermediate portion toward the inner peripheral side and return to the lower radial fluid dynamic pressure bearing portion 39. In this case, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and a pair of upper and lower ring thrust plates 34A. , 35A circulate without passing through the pair of thrust fluid dynamic bearing portions 40, 41.

  Further, as shown in FIG. 5E, when the generation of each dynamic pressure value is c <d and a = b, the lubrication that has exited here through the lower radial fluid dynamic pressure bearing portion 39. 5D, the direction of the arrow is opposite to that shown in FIG. 5D, and the radial direction communication passage 44 provided at an intermediate portion in the inner sleeve 32 is directed to the outer peripheral side. After flowing downwardly through the passage 43 and the outer peripheral gap 48 of the lower ring-shaped thrust plate 35A, and further after moving the radial communication passage 46 provided in the lower ring-shaped thrust plate 35A toward the inner peripheral side It circulates so that it flows upward through a bottomed recess 35c formed on the inner peripheral surface side of the lower ring-shaped thrust plate 35A and returns to the lower radial fluid dynamic bearing portion 39. In this case as well, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and a pair of upper and lower ring thrust plates 34A. , 35A circulate without passing through the pair of thrust fluid dynamic bearing portions 40, 41.

  Accordingly, in the example of FIGS. 5B to 5E, the lubricant 33 that has exited here through one radial fluid dynamic pressure bearing portion 38 (or 39) is transferred to the other radial fluid dynamic pressure bearing portion 39 ( Or 38) and can be circulated without the pair of thrust fluid dynamic pressure bearing portions 40, 41 formed on the pair of upper and lower ring-shaped thrust plates 34A, 35A. Can be returned.

  Further, FIGS. 5 (F) and 5 (G) show the circulation path of the lubricant 33 by the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39. FIG.

  As shown in FIG. 5F, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A> B), the pair of radial fluid dynamic pressure bearings The lubricating oil 33 exiting here through the portions 38 and 39 flows downward through the bottomed recess 35c formed on the inner peripheral surface side of the lower ring-shaped thrust plate 35A as indicated by the arrow. A radial direction communication passage 46 provided in the lower ring-shaped thrust plate 35A flows toward the outer peripheral side, and thereafter, an outer peripheral clearance 48 of the lower ring-shaped thrust plate 35A, a long shaft-direction communication passage 43, and the like. It flows upward through the outer circumferential clearance 47 of the upper ring-shaped thrust plate 34A, and further flows upward through the radial communication passage 45 provided in the upper ring-shaped thrust plate 34A toward the inner circumferential side. Circulating the ring-like thrust plate 34A bottomed recess 34c formed in the inner peripheral surface side of the flow downward to return to the pair of radial fluid dynamic pressure bearing portion 38, 39.

  Further, as shown in FIG. 5G, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A <B), the pair of radial fluid dynamics The lubricating oil 33 exiting through the pressure bearing portions 38 and 39 is formed on the inner peripheral surface side of the upper ring-shaped thrust plate 34A with the direction of the arrow reversed to that of FIG. After flowing upward in the bottom recess 34c, it flows in the radial direction communication path 45 provided in the upper ring-shaped thrust plate 34A toward the outer peripheral side, and thereafter, the outer circumferential gap 47 of the upper ring-shaped thrust plate 34A and It flows downward through the long shaft direction communication path 43 and the outer peripheral gap 48 of the lower ring-shaped thrust plate 35A, and further, a radial direction communication path 46 provided in the lower ring-shaped thrust plate 35A After flowing toward the peripheral side, it flows upward through a bottomed recess 35c formed on the inner peripheral surface side of the lower ring-shaped thrust plate 35A so as to return to the pair of radial fluid dynamic pressure bearing portions 38 and 39. Circulate.

  Next, as shown in FIGS. 6A and 6B, in the fluid dynamic pressure bearing 30A as the main part of the first embodiment, the upper and lower ends of the inner sleeve 32 and a pair of ring-shaped thrust plates 34A. , 35A, a pair of thrust fluid dynamic pressure bearing portions 40 (e, f), 41 (g, h) provided on either one side is, for example, as each thrust fluid dynamic pressure groove as described above. A herringbone that is bent in a “letter shape” is formed, and the dynamic pressure value generated in the lubricant 33 (FIGS. 1 and 2) by each thrust fluid dynamic pressure groove when the rotor R (FIG. 1) is rotated is designed. Although it is set to be the same above, even if the processing accuracy of each thrust fluid dynamic pressure groove is increased, there is a slight difference in the processing accuracy such as verticality and groove shape, so the generated dynamic pressure value A slight difference (dynamic pressure difference) occurs, and the lubricant 33 has a dynamic pressure corresponding to the dynamic pressure difference. Since flows from high direction to a lower direction, by circulating the lubricant 33 to compensate for the shortage of the lubricant 33, it is necessary to feed back the appropriate amount of the lubricant 33.

  Along with the above, the dynamic pressure value generated at the outer peripheral bent portion 40e of the herringbone bent in a “letter shape” in the upper thrust fluid dynamic pressure bearing portion 40 (e, f) is indicated by e, and the inner peripheral bent portion The dynamic pressure value generated at 40f is denoted by f.

Similarly, the dynamic pressure value generated at the outer peripheral bending portion 41g of the herringbone bent in a “letter shape” in the lower thrust fluid dynamic pressure bearing portion 41 (g, h) is indicated by g, and the inner peripheral bending portion 41h. The dynamic pressure value generated in is indicated by h.

  Here, when the inner sleeve 32 rotates, as shown in FIG. 6C, in the above-described dynamic pressure values e to h, the generation of the dynamic pressure values is e> f and g = h. In this case, the lubricant 33 exiting through the upper thrust fluid dynamic pressure bearing portion 40 flows upward in the outer circumferential gap 47 of the upper ring-shaped thrust plate 34A as indicated by the arrow, and thereafter And flows in a radial direction communication passage 45 provided in the upper ring-shaped thrust plate 34A toward the inner peripheral side, and further, a bottomed recess 34c formed on the inner peripheral surface side of the upper ring-shaped thrust plate 34A is directed downward. It circulates so that it may flow toward and return to the upper thrust fluid dynamic pressure bearing 40. In this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 disposed below the upper thrust fluid dynamic pressure bearing portion 40, and a pair of radial fluid dynamic pressure bearing portions. It circulates through 38,39.

  Further, as shown in FIG. 6D, when the generation of each dynamic pressure value is e <f and g = h, the lubricant that has left here through the upper thrust fluid dynamic pressure bearing portion 40. 33 flows upward in a bottomed recess 34c formed on the inner peripheral surface side of the upper ring-shaped thrust plate 34A with the direction of the arrow opposite to that in FIG. 6C, and then the upper side. The radial thrust passage 34 provided in the ring-shaped thrust plate 34A flows toward the outer peripheral side, and further flows downwardly through the outer peripheral clearance 47 of the upper ring-shaped thrust plate 34A. Cycle to return to 40. Also in this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 disposed below the upper thrust fluid dynamic pressure bearing portion 40, and a pair of radial fluid dynamic pressure bearing portions. It circulates through 38,39.

  Further, as shown in FIG. 6E, when the generation of each dynamic pressure value is g> h and e = f, the lubrication exiting through the lower thrust fluid dynamic pressure bearing 41 is provided. The agent 33 flows downward through the outer circumferential gap 48 of the lower ring-shaped thrust plate 35A as indicated by an arrow, and thereafter, the radial direction communication passage 46 provided in the lower ring-shaped thrust plate 35A It flows toward the inner peripheral side, and further flows upward through a bottomed recess 35c formed on the inner peripheral surface side of the lower ring-shaped thrust plate 35A so as to return to the lower thrust fluid dynamic pressure bearing portion 41. It circulates to. In this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 disposed above the lower thrust fluid dynamic pressure bearing portion 41, and a pair of radial fluid dynamic pressure bearing portions. It circulates through 38,39.

  Further, as shown in FIG. 6F, when the generation of each dynamic pressure value is g <h and e = f, the lubrication that has exited through the lower thrust fluid dynamic pressure bearing 41 is provided. The agent 33 flows downward in the bottomed recess 35c formed on the inner peripheral surface side of the lower ring-shaped thrust plate 35A with the direction of the arrow reversed with respect to FIG. The radial direction communication passage 46 provided in the lower ring-shaped thrust plate 35A flows toward the outer peripheral side, and further flows upward through the outer peripheral gap 48 of the lower ring-shaped thrust plate 35A to lower the lower thrust. It circulates back to the fluid dynamic bearing 41. Also in this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 disposed above the lower thrust fluid dynamic pressure bearing portion 41, and a pair of radial fluid dynamic pressure bearing portions. It circulates through 38,39.

  Accordingly, in the example of FIGS. 6C to 6F, the lubricant 33 that has exited here through one thrust fluid dynamic pressure bearing portion 40 (or 41) is transferred to the other thrust fluid dynamic pressure bearing portion 41 ( Alternatively, the lubricant 33 can be circulated without going through 40) and can be circulated without going through the pair of radial fluid dynamic pressure bearing portions 38, 39, so that the lubricant 33 can be returned in an appropriate amount.

  From the above, each radial fluid dynamic pressure bearing portion of the pair of radial fluid dynamic pressure bearing portions 38, 39 and each thrust fluid dynamic pressure bearing portion of the pair of thrust fluid dynamic pressure bearing portions 40, 41 are each fluid dynamic pressure bearing portion. The lubricant 33 can be circulated without using any fluid dynamic pressure bearing other than itself.

FIG. 7 is a longitudinal sectional view showing, in an enlarged manner, a fluid dynamic pressure bearing, which is a main part of Example 2, in the fluid dynamic pressure bearing motor of Example 2 according to the present invention,
FIGS. 8A to 8G are diagrams schematically illustrating the operation of a pair of radial fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are essential portions of the second embodiment,
FIGS. 9A to 9F are diagrams schematically showing the operation of a pair of thrust fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are the main portions of the second embodiment.

  As shown in an enlarged view in FIG. 7, in the fluid dynamic pressure bearing motor 10 </ b> B (not shown) according to the second embodiment of the present invention, the fluid dynamic pressure bearing 30 </ b> B, which is the main part of the second embodiment, A pair provided between the surface 12a and the inner peripheral surface of the center hole 32b of the inner sleeve 32 and having predetermined axial lengths L1 and L2, respectively, spaced along the shaft direction on either side. Each of the radial fluid dynamic pressure grooves of the radial fluid dynamic pressure bearing portions 38, 39, the upper and lower ends of the inner sleeve 32, and the pair of ring-shaped thrust plates 34A, 35A previously described with reference to FIG. The thrust fluid dynamic pressure grooves of the pair of thrust fluid dynamic pressure bearing portions 40, 41 provided on either one side between the lower surface and the upper surface are the same as those in the first embodiment described above.

  On the other hand, different points from the first embodiment will be described. In the fluid dynamic pressure bearing 30B, which is a main part of the second embodiment, a long shaft direction communication path (vertical communication path) 51 is formed in the shaft direction in the shaft 12. It is provided along. Further, a radial direction communication path (lateral communication path) 52 is provided in an intermediate portion in the shaft direction in the shaft 12, and one end side of the radial direction communication passage 52 communicates with the intermediate portion of the shaft direction communication path 51 and others. The end side communicates between the pair of radial fluid dynamic bearing portions 38 and 39. Further, a pair of radial communication paths (lateral communication paths) 53 and 54 are provided in the shaft 12 in the upper and lower portions in the shaft direction, and one end side of each of the pair of radial communication paths 53 and 54 is a shaft direction communication path. The other end side communicates with a pair of radial communication paths (lateral communication paths) 45 and 46 provided in a pair of upper and lower ring-shaped thrust plates 34A and 35A.

  At this time, the other end sides of the pair of radial communication paths 53 and 54 provided at the upper and lower parts in the shaft 12 are respectively formed on the inner peripheral surface sides of the pair of upper and lower ring-shaped thrust plates 34A and 35A. The pair of radial fluid dynamic pressure bearing portions 38 and 39 are also communicated with the upper and lower portions positioned above and below the pair of radial fluid dynamic pressure bearing portions 38 and 39 via the bottom recesses 34c and 35c.

  At this time, since the long shaft direction communication path 51 provided along the shaft direction in the shaft 12 is vertically drilled downward from the upper end of the shaft 12, the shaft direction communication path Since the upper part of 51 is open, in order to prevent the lubricant 33 from evaporating, a blocking plug 55 made of an elastic member is adhered to the upper part of the shaft direction communication path 51 with an adhesive, and the shaft direction communication path 51. The upper part of is closed.

  Here, operation | movement of a pair of radial fluid dynamic pressure bearing parts 38 and 39 among the fluid dynamic pressure bearings 30B used as the principal part of Example 2 is demonstrated using FIG.

  As shown in FIG. 8A, in the second embodiment, as in the first embodiment, the dynamics generated by the radial fluid dynamic pressure grooves 38a, 38b, 39c, 39d of the pair of radial fluid dynamic pressure bearing portions 38, 39 are the same. When a slight difference (dynamic pressure difference) occurs in the pressure values a to d, the lubricant 33 flows from the high pressure value toward the low pressure according to the dynamic pressure difference, so that the shortage of the lubricant 33 is compensated. It is necessary to circulate the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in the second embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 8B, in each of the above-described dynamic pressure values a to d, the generation of the dynamic pressure values is a> b, c = In the case of d, the lubricant 33 exiting through the upper radial fluid dynamic pressure bearing portion 38 enters the radial communication passage 52 provided at the intermediate portion in the shaft 12 as indicated by an arrow. It goes to the circumferential side, and then flows upward in the long shaft direction communication passage 51 provided in the shaft 12, and further, the radial direction communication passage 53 provided in the upper portion in the shaft 12 toward the outer periphery side. Circulates so as to flow downward through the bottomed recess 34c formed on the inner peripheral surface side of the upper ring-shaped thrust plate 34A and back to the upper radial fluid dynamic bearing portion 38. In this case, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and a pair of upper and lower ring-shaped thrust plates 34A, The pair of thrust fluid dynamic pressure bearing portions 40 and 41 formed in 35A is not interposed.

  Further, as shown in FIG. 8C, when the generation of each dynamic pressure value is a <b and c = d, the lubricant that has left here through the upper radial fluid dynamic bearing portion 38. Since 33 circulates in a direction opposite to that shown in FIG. 8B, the fluid dynamic pressure bearing portions 39, 40, and 41 are not interposed here.

  Further, as shown in FIG. 8D, when the generation of each dynamic pressure value is c> d and a = b, the lubrication that has exited through the lower radial fluid dynamic bearing portion 39 is provided. The agent 33 flows downward in a bottomed recess 35c formed on the inner peripheral surface side of the lower ring-shaped thrust plate 35A as indicated by an arrow and is provided in a lower portion in the shaft 12 in the radial direction communication path. 54 is directed to the inner peripheral side, and then flows upward in a long shaft direction communication path 51 provided in the shaft 12, and further, a radial direction communication path 52 provided in an intermediate portion in the shaft 12 is It circulates so that it may flow toward the side and return to the lower radial fluid dynamic pressure bearing portion 39. In this case, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and a pair of upper and lower ring thrust plates 34A. , 35A, a pair of thrust fluid dynamic bearing portions 40, 41 are not interposed.

  Further, as shown in FIG. 8E, when the occurrence of each dynamic pressure value is c <d and a = b, the lubrication that has exited through the lower radial fluid dynamic bearing portion 39 is provided. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 8D described above, the other fluid dynamic pressure bearing portions 38, 40, and 41 are not interposed here.

  Accordingly, in the example of FIGS. 8B to 8E, the lubricant 33 that has exited here through one radial fluid dynamic pressure bearing portion 38 (or 39) is transferred to the other radial fluid dynamic pressure bearing portion 39 ( Or 38) and can be circulated without the pair of thrust fluid dynamic pressure bearing portions 40, 41 formed on the pair of upper and lower ring-shaped thrust plates 34A, 35A. Can be returned.

  Further, FIGS. 8F and 8G show the circulation path of the lubricant 33 by the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39. FIG.

  As shown in FIG. 8F, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A> B), the pair of radial fluid dynamic pressure bearings The lubricating oil 33 passing through the portions 38 and 39 flows downward in a bottomed recess 35c formed on the inner peripheral surface side of the lower ring-shaped thrust plate 35A as indicated by an arrow, and is a lower part in the shaft 12. The radial direction communication passage 54 provided in the shaft 12 is directed toward the inner peripheral side, and thereafter, the long shaft direction communication passage 51 provided in the shaft 12 flows upward, and further provided in an upper portion of the shaft 12. A pair of radial fluid dynamic pressure bearing portions 38 flowing downward in a bottomed recess 34c formed on the inner peripheral surface side of the upper ring-shaped thrust plate 34A after flowing in the radial direction communication passage 53 toward the outer peripheral side, Return to 39 Sea urchin circulating.

  As shown in FIG. 8G, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A <B), the pair of radial fluid dynamics The lubricating oil 33 passing through the pressure bearing portions 38 and 39 flows in the opposite direction to the above FIG. 8F and circulates.

  Next, operations of the pair of thrust fluid dynamic pressure bearing portions 40 and 41 in the fluid dynamic pressure bearing 30B, which is a main part of the second embodiment, will be described with reference to FIG.

  As shown in FIGS. 9A and 9B, in the second embodiment, as in the first embodiment, a pair of thrust fluid dynamic pressure bearing portions 40 (e, e) formed on a pair of upper and lower ring-shaped thrust plates 34A, 35A. When a slight difference (dynamic pressure difference) is generated in the dynamic pressure values e to h generated by the thrust fluid dynamic pressure grooves 40e, 40f, 41g, and 41h of f) and 41 (g, h), the lubricant 33 has a dynamic pressure difference. Accordingly, it is necessary to return the appropriate amount of the lubricant 33 by circulating the lubricant 33 in order to compensate for the insufficient amount of the lubricant 33.

  Therefore, in the second embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 9C, in each of the dynamic pressure values e to h described above, the generation of the dynamic pressure values is e> f, g = In the case of h, the lubricant 33 exiting through the upper thrust fluid dynamic pressure bearing 40 is formed on the inner peripheral surface side of the upper ring-shaped thrust plate 34A as indicated by an arrow. It flows upward in the bottom recess 34c, and then flows in the radial direction communication passage 45 formed in the upper ring-shaped thrust plate 34A toward the outer peripheral side, and further, the outer peripheral gap 47 of the upper ring-shaped thrust plate 34A. Is circulated so as to return downward to the upper thrust fluid dynamic pressure bearing 40. In this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 disposed below the upper thrust fluid dynamic pressure bearing portion 40, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  Further, as shown in FIG. 9D, when the generation of each dynamic pressure value is e <f and g = h, the lubricant that has left here through the upper thrust fluid dynamic pressure bearing portion 40. Since 33 circulates in the opposite direction with respect to FIG. 9 (C) described above, the other fluid dynamic pressure bearing portions 38, 39, and 41 are not interposed here.

  Further, as shown in FIG. 9 (E), when the generation of each dynamic pressure value is g> h and e = f, the lubrication exiting through the lower thrust fluid dynamic bearing portion 41 is provided. The agent 33 flows downward through the outer peripheral gap 48 of the lower ring-shaped thrust plate 35A as indicated by an arrow, and thereafter the radial direction communication passage 46 formed in the lower ring-shaped thrust plate 35A. It flows toward the inner peripheral side, and further flows upward through a bottomed recess 35c formed on the inner peripheral surface side of the lower ring-shaped thrust plate 35A so as to return to the lower thrust fluid dynamic pressure bearing portion 41. It circulates to. In this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 disposed above the lower thrust fluid dynamic pressure bearing portion 41, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  Further, as shown in FIG. 9F, when the generation of each dynamic pressure value is g <h and e = f, the lubrication that has exited through the lower thrust fluid dynamic pressure bearing 41 is provided. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 9 (E), the fluid dynamic pressure bearing portions 38, 39, and 40 are not interposed here.

  Accordingly, in the example of FIGS. 9C to 9F, the lubricant 33 that has exited here through one thrust fluid dynamic pressure bearing portion 40 (or 41) is transferred to the other thrust fluid dynamic pressure bearing portion 41 ( Alternatively, the lubricant 33 can be circulated without going through 40) and can be circulated without going through the pair of radial fluid dynamic pressure bearing portions 38, 39, so that the lubricant 33 can be returned in an appropriate amount.

FIG. 10 is a longitudinal sectional view showing, in an enlarged manner, a fluid dynamic pressure bearing, which is a main part of Example 3, in the fluid dynamic pressure bearing motor of Example 3 according to the present invention.
FIGS. 11A to 11G are diagrams schematically illustrating the operation of a pair of radial fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are essential portions of the third embodiment,
FIGS. 12A to 12F are diagrams schematically illustrating the operation of a pair of thrust fluid dynamic pressure bearings among the fluid dynamic pressure bearings that are the main parts of the third embodiment.

  As shown in an enlarged view in FIG. 10, in the fluid dynamic pressure bearing motor 10 </ b> C (not shown) according to the third embodiment of the present invention, the fluid dynamic pressure bearing 30 </ b> C, which is the main part of the third embodiment, has an outer periphery of the shaft 12. A pair provided between the surface 12a and the inner peripheral surface of the center hole 32b of the inner sleeve 32 and having predetermined axial lengths L1 and L2, respectively, spaced along the shaft direction on either side. The radial fluid dynamic pressure bearing portions 38 and 39 of each of the radial fluid dynamic pressure grooves and the outer sleeve 31 and the inner sleeve 32 are provided with at least one or more along the shaft direction on either side. Shaft-direction communication passages (vertical communication passages) 42 and 43, and an intermediate portion in the shaft direction in the inner sleeve 32, which is provided in the radial direction, and has one end side between the pair of radial fluid dynamic pressure bearing portions 38 and 39. Through and the other end is the same for the first embodiment described in the radial direction communicating channel (Yokoren passage) 44 Togasaki communicating with the intermediate portion of the shaft direction communicating channel 42, 43.

  On the other hand, different points from the first embodiment will be described. In the fluid dynamic pressure bearing 30C, which is the main part of the third embodiment, the thrust fluid dynamic pressure grooves of the pair of thrust fluid dynamic bearing portions 40, 41 are inner sleeves. 32 is provided on either side between the upper and lower end portions of 32 and the lower and upper surfaces of the pair of ring-shaped thrust plates 34E and 35E described above with reference to FIG. Further, a pair of radial communication paths (lateral communication paths) 56 and 57 are provided in the upper and lower portions of the inner sleeve 32 in the shaft direction, and one end of each of the pair of radial communication paths 56 and 57 is a pair of radials. The corner portions 32c and 32d formed at the upper and lower portions positioned above and below the pair of radial fluid dynamic pressure bearing portions 38 and 39 on the fluid dynamic pressure bearing portions 38 and 39 and at the upper and lower ends on the inner peripheral side of the inner sleeve 32, respectively. The other end side communicates with the upper and lower parts of the shaft direction communication passages 42 and 43, respectively.

  Here, operation | movement of a pair of radial fluid dynamic pressure bearing parts 38 and 39 among the fluid dynamic pressure bearings 30C used as the principal part of Example 3 is demonstrated using FIG.

  As shown in FIG. 11A, in the third embodiment as well as in the first and second embodiments, the radial fluid dynamic pressure grooves 38a, 38b, 39c, and 39d of the pair of radial fluid dynamic pressure bearing portions 38 and 39 generate each other. When a slight difference (dynamic pressure difference) occurs between the dynamic pressure values a to d, the lubricant 33 flows from the high pressure value toward the low direction according to the dynamic pressure difference. In order to compensate, it is necessary to circulate the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in the third embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 11B, in each of the above-described dynamic pressure values a to d, the generation of the dynamic pressure values is a> b, c = In the case of d, the lubricant 33 that has exited through the upper radial fluid dynamic pressure bearing portion 38 passes through the radial communication path 44 provided at the intermediate portion in the inner sleeve 32 as indicated by an arrow. It goes to the outer peripheral side, and then flows upward in a long shaft direction communication path 43 provided between the outer sleeve 31 and the inner sleeve 32, and is further provided in a radial direction provided at an upper portion in the inner sleeve 32. It circulates so as to flow through the communication path 56 toward the inner peripheral side and return to the upper radial fluid dynamic pressure bearing portion 38. In this case, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and a pair of upper and lower ring-shaped thrust plates 34E, The pair of thrust fluid dynamic pressure bearing portions 40 and 41 formed in 35E is not interposed.

  Further, as shown in FIG. 11C, when the occurrence of each dynamic pressure value is a <b and c = d, the lubricant that has exited here through the upper radial fluid dynamic bearing portion 38. Since 33 circulates in the opposite direction with respect to FIG. 11 (B) described above, the other fluid dynamic pressure bearing portions 39, 40, 41 are not interposed here.

  Further, as shown in FIG. 11D, when the generation of each dynamic pressure value is c> d and a = b, the lubrication exiting through the lower radial fluid dynamic bearing portion 39 is provided. As indicated by the arrow, the agent 33 moves to the outer peripheral side through the radial communication path 57 provided in the lower part of the inner sleeve 32, and then flows upward through the long shaft communication path 43. Then, it circulates so as to flow in the radial direction communication passage 44 provided at the intermediate portion in the inner sleeve 32 toward the inner peripheral side and to return to the lower radial fluid dynamic pressure bearing portion 39. In this case, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and a pair of upper and lower ring thrust plates 34E. , 35E is not interposed with a pair of thrust fluid dynamic pressure bearing portions 40, 41.

  Further, as shown in FIG. 11 (E), when the occurrence of each dynamic pressure value is c <d and a = b, the lubrication that has exited through the lower radial fluid dynamic bearing portion 39 is provided. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 11D described above, the other fluid dynamic pressure bearing portions 38, 40, and 41 are not interposed here.

  Accordingly, in the example of FIGS. 11B to 11E, the lubricant 33 that has exited here through one radial fluid dynamic pressure bearing portion 38 (or 39) is transferred to the other radial fluid dynamic pressure bearing portion 39 ( Or 38) and can be circulated without the pair of thrust fluid dynamic pressure bearing portions 40, 41 formed on the pair of upper and lower ring-shaped thrust plates 34E, 35E. Can be returned.

  Further, FIGS. 11 (F) and 11 (G) show the circulation path of the lubricant 33 by the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39. FIG.

  As shown in FIG. 11F, in the third embodiment, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A> B), The lubricating oil 33 passing through the radial fluid dynamic bearings 38 and 39 is directed to the outer peripheral side through a radial communication path 57 provided at a lower portion in the inner sleeve 32 as indicated by an arrow. Flows upward in the directional communication passage 43, and further flows in a radial direction communication hole 56 provided in an upper portion of the inner sleeve 32 toward the inner peripheral side to return to the pair of radial fluid dynamic pressure bearing portions 38, 39. Circulate like so.

  In addition, as shown in FIG. 11G, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A <B), the pair of radial fluid dynamics The lubricating oil 33 passing through the pressure bearing portions 38 and 39 flows and circulates in the opposite direction with respect to FIG.

  Next, operations of the pair of thrust fluid dynamic pressure bearing portions 40 and 41 in the fluid dynamic pressure bearing 30C, which is a main part of the third embodiment, will be described with reference to FIG.

  As shown in FIGS. 12A and 12B, each of the pair of thrust fluid dynamic pressure bearing portions 40 (e, f), 41 (g, h) formed on the pair of upper and lower ring-shaped thrust plates 34E, 35E. When a slight difference (dynamic pressure difference) is generated in the dynamic pressure values e to h generated by the thrust fluid dynamic pressure grooves 40e, 40f, 41g, and 41h, the lubricant 33 decreases from the higher dynamic pressure value according to the dynamic pressure difference. Since it flows in the direction, it is necessary to circulate the lubricant 33 in order to compensate for the insufficient amount of the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in the third embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 12C, in each of the dynamic pressure values e to h described above, the generation of the dynamic pressure values is e> f, g = In the case of h, the lubricant 33 that has exited through the upper thrust fluid dynamic pressure bearing portion 40 has a corner portion 32c formed on the inner peripheral upper portion of the inner sleeve 32 downward as shown by an arrow. After that, the radial direction communication passage 56 provided in the upper part in the inner sleeve 32 is directed to the outer peripheral side, and further flows upward in the shaft direction communication passage 43 to be the upper thrust fluid dynamic pressure bearing portion. Cycle to return to 40. In this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 disposed below the upper thrust fluid dynamic pressure bearing portion 40, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  Further, as shown in FIG. 12D, when the generation of each dynamic pressure value is e <f and g = h, the lubricant that has left here through the upper thrust fluid dynamic pressure bearing portion 40. Since 33 circulates in a direction opposite to that shown in FIG. 12C, the fluid dynamic pressure bearing portions 38, 39, 41 are not interposed here.

  Further, as shown in FIG. 12E, when the generation of each dynamic pressure value is g> h and e = f, the lubrication that has exited through the lower thrust fluid dynamic pressure bearing portion 41 is provided. The agent 33 flows upward in the corner portion 32d formed in the lower inner periphery of the inner sleeve 32 as indicated by the arrow, and then passes through the radial communication path 57 provided in the lower portion in the inner sleeve 32 to the outer periphery. Further, it circulates so as to flow downward in the shaft direction communication path 43 and return to the lower thrust fluid dynamic bearing portion 41. In this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 disposed above the lower thrust fluid dynamic pressure bearing portion 41, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  Also, as shown in FIG. 12 (F), when the generation of each dynamic pressure value is g <h and e = f, the lubrication that exits here through the lower thrust fluid dynamic pressure bearing portion 41. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 12 (E) described above, the fluid dynamic pressure bearing portions 38, 39, and 40 are not interposed here.

  Accordingly, in the example of FIGS. 12C to 12F, the lubricant 33 that has exited here through one thrust fluid dynamic pressure bearing portion 40 (or 41) is transferred to the other thrust fluid dynamic pressure bearing portion 41 ( Alternatively, the lubricant 33 can be circulated without going through 40) and can be circulated without going through the pair of radial fluid dynamic pressure bearing portions 38, 39, so that the lubricant 33 can be returned in an appropriate amount.

FIGS. 13A to 13G are diagrams schematically illustrating the operation of a pair of radial fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are essential portions of the fourth embodiment,
FIGS. 14A to 14F are diagrams schematically showing the operation of a pair of thrust fluid dynamic pressure bearings among the fluid dynamic pressure bearings that are the main part of the fourth embodiment.

  In a fluid dynamic pressure bearing motor 10D (not shown) according to the fourth embodiment of the present invention, as shown in FIG. 13A, the fluid dynamic pressure bearing 30D, which is the main part of the fourth embodiment, has an outer periphery of the shaft 12. A pair of radial fluid dynamic pressure bearing portions 38 each having a predetermined axial length with an interval along the shaft direction on either side between the surface and the inner peripheral surface of the inner sleeve 32. , 39 are the same as those of the first to third embodiments described above, and a long shaft direction communication path (longitudinal connection) provided in the shaft 12 along the shaft direction. 51), a radial direction communication path (lateral communication path) 52 provided in an intermediate portion in the shaft direction within the shaft 12, and a pair of radial direction communication paths provided in upper and lower portions in the shaft direction within the shaft 12 Horizontal communication passage) 53 54 is the same for the second embodiment described Togasaki. At this time, the upper portion of the long shaft direction communication path (longitudinal communication path) 51 provided along the shaft direction in the shaft 12 is for preventing evaporation of the lubricant 33 as in the second embodiment. The lid is closed by a closing plug 55 made of an elastic member.

  On the other hand, different points from the first and second embodiments will be described. In the fluid dynamic pressure bearing 30D, which is a main part of the fourth embodiment, the thrust fluid dynamic pressure grooves of the pair of thrust fluid dynamic pressure bearing portions 40 and 41 are provided. It is provided between the upper and lower ends of the inner sleeve 32 and the lower and upper surfaces of the pair of ring-shaped thrust plates 34E and 35E previously described with reference to FIG. In addition, a pair of radial communication paths (lateral communication paths) 56 and 57 are provided at the upper and lower parts in the inner sleeve 32, and one end side of the pair of radial communication paths 56 and 57 is the upper and lower parts in the shaft 12. The other end side communicates with a short outer circumferential gap 58, 59 formed along the shaft direction on the outer circumferential upper and lower portions of the inner sleeve 32.

  Further, one end side of the pair of radial communication passages 53 and 54 provided at the upper and lower portions in the shaft 12 is a pair of radial fluid dynamic pressure bearing portions 38 and 39 on the side of the pair of radial fluid dynamic pressure bearing portions 38. , 39 communicates with the upper and lower parts located above and below.

  Here, operation | movement of a pair of radial fluid dynamic pressure bearing parts 38 and 39 among the fluid dynamic pressure bearings 30D used as the principal part of Example 4 is demonstrated using FIG.

  As shown in FIG. 13A, in the fourth embodiment as well as in the first to third embodiments, the radial fluid dynamic pressure grooves 38a, 38b, 39c, and 39d of the pair of radial fluid dynamic pressure bearing portions 38 and 39 generate each other. When a slight difference (dynamic pressure difference) occurs between the dynamic pressure values a to d, the lubricant 33 flows from the high pressure value toward the low direction according to the dynamic pressure difference. In order to compensate, it is necessary to circulate the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in the fourth embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 13B, in each of the above-described dynamic pressure values a to d, the generation of the dynamic pressure values is a> b, c = In the case of d, the lubricant 33 exiting through the upper radial fluid dynamic pressure bearing portion 38 enters the radial communication passage 52 provided at the intermediate portion in the shaft 12 as indicated by an arrow. It goes to the circumferential side, and then flows upward in the long shaft direction communication passage 51 provided in the shaft 12, and further, the radial direction communication passage 53 provided in the upper portion in the shaft 12 toward the outer periphery side. And circulates back to the upper radial fluid dynamic bearing portion 38. In this case, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and a pair of upper and lower ring-shaped thrust plates 34E, The pair of thrust fluid dynamic pressure bearing portions 40 and 41 formed in 35E is not interposed.

  Further, as shown in FIG. 13C, when the generation of each dynamic pressure value is a <b, c = d, the lubricant that has left here through the upper radial fluid dynamic bearing portion 38. Since 33 circulates in a direction opposite to that shown in FIG. 13B, the fluid dynamic pressure bearing portions 39, 40, and 41 are not interposed here.

  Further, as shown in FIG. 13D, when the generation of each dynamic pressure value is c> d and a = b, the lubrication that exits here through the lower radial fluid dynamic bearing portion 39. As indicated by the arrow, the agent 33 is directed toward the inner circumferential side of the radial communication path 54 provided in the lower portion of the shaft 12, and then the upper shaft direction communication path 51 provided in the shaft 12 is moved upward. Furthermore, it circulates in a radial direction communication passage 52 provided at an intermediate portion in the shaft 12 so as to flow toward the outer peripheral side and return to the lower radial fluid dynamic pressure bearing portion 39. In this case, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and a pair of upper and lower ring thrust plates 34E. , 35E is not interposed with a pair of thrust fluid dynamic pressure bearing portions 40, 41.

  Further, as shown in FIG. 13 (E), when the occurrence of each dynamic pressure value is c <d and a = b, the lubrication that exits here through the lower radial fluid dynamic bearing portion 39. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 13D described above, the other fluid dynamic pressure bearing portions 38, 40, and 41 are not interposed here.

  Accordingly, in the example of FIGS. 13B to 13E, the lubricant 33 that has exited through one radial fluid dynamic pressure bearing portion 38 (or 39) is transferred to the other radial fluid dynamic pressure bearing portion 39 ( Or 38) and can be circulated without the pair of thrust fluid dynamic pressure bearing portions 40, 41 formed on the pair of upper and lower ring-shaped thrust plates 34E, 35E. Can be returned.

  Further, FIGS. 13 (F) and 13 (G) show the circulation path of the lubricant 33 by the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39. FIG.

  As shown in FIG. 13F, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A> B), the pair of radial fluid dynamic pressure bearings The lubricating oil 33 passing through the portions 38 and 39 is directed to the radial communication path 54 provided in the lower part of the shaft 12 toward the inner peripheral side as indicated by an arrow, and thereafter, the long oil provided in the shaft 12 is used. The shaft direction communication path 51 flows upward, and further flows in the radial direction communication path 53 provided in the upper portion of the shaft 12 toward the outer peripheral side so as to return to the pair of radial fluid dynamic pressure bearing portions 38 and 39. It circulates to.

  In addition, as shown in FIG. 13G, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A <B), the pair of radial fluid dynamics The lubricating oil 33 passing through the pressure bearing portions 38 and 39 flows in the reverse direction with respect to FIG.

  Next, operations of the pair of thrust fluid dynamic pressure bearing portions 40 and 41 in the fluid dynamic pressure bearing 30D which is a main part of the fourth embodiment will be described with reference to FIG.

  As shown in FIGS. 14A and 14B, in the fourth embodiment, as in the third embodiment, a pair of thrust fluid dynamic pressure bearing portions 40 (e, e) formed on a pair of upper and lower ring-shaped thrust plates 34E, 35E. When a slight difference (dynamic pressure difference) is generated in the dynamic pressure values e to h generated by the thrust fluid dynamic pressure grooves 40e, 40f, 41g, and 41h of f) and 41 (g, h), the lubricant 33 has a dynamic pressure difference. Accordingly, it is necessary to return the appropriate amount of the lubricant 33 by circulating the lubricant 33 in order to compensate for the insufficient amount of the lubricant 33.

  Therefore, in the fourth embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 14C, in each of the dynamic pressure values e to h described above, the generation of the dynamic pressure values is e> f, g = In the case of h, the lubricant 33 that has exited through the upper thrust fluid dynamic pressure bearing portion 40 has a corner portion 32c formed on the inner peripheral upper portion of the inner sleeve 32 downward as shown by an arrow. After that, the radial direction communication path 56 provided in the upper part of the inner sleeve 32 is directed to the outer peripheral side, and further flows upward in the outer peripheral gap 58 provided in the upper outer peripheral part of the inner sleeve 32. And circulates back to the upper thrust fluid dynamic bearing 40. In this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 disposed below the upper thrust fluid dynamic pressure bearing portion 40, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  Further, as shown in FIG. 14D, when the generation of each dynamic pressure value is e <f, g = h, the lubricant that has left here through the upper thrust fluid dynamic pressure bearing portion 40. Since 33 flows and circulates in the opposite direction with respect to FIG. 14C described above, the other fluid dynamic pressure bearing portions 38, 39, 41 are not interposed here.

  Further, as shown in FIG. 14E, when the generation of each dynamic pressure value is g> h and e = f, the lubrication exiting through the lower thrust fluid dynamic pressure bearing portion 41 is provided. The agent 33 flows upward in the corner portion 32d formed in the lower inner periphery of the inner sleeve 32 as indicated by the arrow, and then passes through the radial communication path 57 provided in the lower portion in the inner sleeve 32 to the outer periphery. Further, it circulates so as to flow downward in the outer peripheral clearance 59 provided in the lower outer peripheral portion of the inner sleeve 32 and return to the lower thrust fluid dynamic pressure bearing portion 41. In this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 disposed above the lower thrust fluid dynamic pressure bearing portion 41, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  Further, as shown in FIG. 14F, when the generation of each dynamic pressure value is g <h and e = f, the lubrication that has exited through the lower thrust fluid dynamic pressure bearing portion 41 is provided. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 14 (E), the fluid dynamic pressure bearing portions 38, 39, and 40 are not interposed here.

  Accordingly, in the example of FIGS. 14C to 14F, the lubricant 33 that has exited here through one thrust fluid dynamic pressure bearing portion 40 (or 41) is transferred to the other thrust fluid dynamic pressure bearing portion 41 ( Alternatively, the lubricant 33 can be circulated without going through 40) and can be circulated without going through the pair of radial fluid dynamic pressure bearing portions 38, 39, so that the lubricant 33 can be returned in an appropriate amount.

FIGS. 15A to 15G are diagrams schematically illustrating the operation of a pair of radial fluid dynamic pressure bearings among the fluid dynamic pressure bearings that are essential parts of the fifth embodiment,
FIGS. 16A to 16F are schematic views for explaining the operation of a pair of thrust fluid dynamic bearings among the fluid dynamic pressure bearings that are the main part of the fifth embodiment.

  In a fluid dynamic bearing motor 10E (not shown) according to the fifth embodiment of the present invention, as shown in FIG. 15A, the fluid dynamic bearing 30E, which is the main part of the fifth embodiment, has an outer periphery of the shaft 12. A pair of radial fluid dynamic pressure bearing portions 38 each having a predetermined axial length with an interval along the shaft direction on either side between the surface and the inner peripheral surface of the inner sleeve 32. , 39 are the same as those of the first to fourth embodiments described above, and a long shaft direction communication path (longitudinal connection) provided in the shaft 12 along the shaft direction. 51), a radial direction communication path (lateral communication path) 52 provided in an intermediate portion in the shaft direction within the shaft 12, and a pair of radial direction communication paths provided in upper and lower portions in the shaft direction within the shaft 12 Horizontal communication passage) 53 It described 54 Togasaki the same for Examples 2 and 4. At this time, the upper portion of the long shaft direction communication path (longitudinal communication path) 51 provided along the shaft direction in the shaft 12 prevents evaporation of the lubricant 33 as in the second and fourth embodiments. It is closed with a closing plug 55 made of an elastic member.

  Further, one end side of the pair of radial communication passages 53 and 54 provided at the upper and lower parts in the shaft 12 is a pair of radial fluid dynamic pressure bearing portions 38 and 39 side, and the pair of radial fluid dynamic pressure bearing portions 38. , 39 communicates with the upper and lower parts located above and below.

  On the other hand, different points from the first, second, and fourth embodiments will be described. In the fluid dynamic pressure bearing 30E that is a main part of the fifth embodiment, the inner sleeve 32 is in contact with the upper end portion in the shaft direction and above the shaft 12. Only the ring-shaped thrust plate 34B described above with reference to FIG. 3B is fixed to the portion, and the ring-shaped thrust plate is not fixed to the lower portion of the shaft 12. Along with this, by forming each thrust fluid dynamic pressure groove by herringbone or a Rayleigh step on the upper and lower surfaces (both sides) of the upper ring-shaped thrust plate 34B, the upper ring-shaped counter plate 36 and the upper ring-shaped thrust plate 34B An upper thrust fluid dynamic pressure bearing portion 40 ′ is provided between the ring-shaped thrust plate 34 B and the lower thrust fluid dynamic pressure between the upper ring-shaped thrust plate 34 B and the upper end portion of the inner sleeve 32. A bearing portion 41 'is provided. Further, a radial communication path (lateral communication path) 45 is provided in the upper ring-shaped thrust plate 34B, and a radial communication path 53 in which one end side of the radial communication path 45 is provided at an upper portion in the shaft 12 is provided. And the other end is in communication with the outer peripheral gap 47 of the ring-shaped thrust plate 34B.

  Here, operation | movement of a pair of radial fluid dynamic pressure bearing parts 38 and 39 among the fluid dynamic pressure bearings 30E used as the principal part of Example 5 is demonstrated using FIG.

  As shown in FIG. 15A, in the fifth embodiment as well as in the first to fourth embodiments, the radial fluid dynamic pressure grooves 38a, 38b, 39c, and 39d of the pair of radial fluid dynamic pressure bearing portions 38 and 39 generate each other. When a slight difference (dynamic pressure difference) occurs between the dynamic pressure values a to d, the lubricant 33 flows from the high pressure value toward the low direction according to the dynamic pressure difference. In order to compensate, it is necessary to circulate the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in the fifth embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 15B, in each of the dynamic pressure values a to d described above, the generation of the dynamic pressure values is a> b, c = In the case of d, the lubricant 33 exiting through the upper radial fluid dynamic pressure bearing portion 38 enters the radial communication passage 52 provided at the intermediate portion in the shaft 12 as indicated by an arrow. It goes to the circumferential side, and then flows upward in the long shaft direction communication passage 51 provided in the shaft 12, and further, the radial direction communication passage 53 provided in the upper portion in the shaft 12 toward the outer periphery side. And circulates back to the upper radial fluid dynamic bearing portion 38. In this case, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and also on the upper ring-shaped thrust plate 34B. The pair of thrust fluid dynamic pressure bearing portions 40 'and 41' formed on the lower surface is not interposed.

  Further, as shown in FIG. 15C, when the generation of each dynamic pressure value is a <b and c = d, the lubricant that has exited through the upper radial fluid dynamic bearing portion 38 is shown. Since 33 flows and circulates in the opposite direction with respect to FIG. 15 (B), it does not pass through other fluid dynamic pressure bearing portions 39, 40 ′, 41 ′.

  Further, as shown in FIG. 15D, when the generation of each dynamic pressure value is c> d and a = b, the lubrication that has exited through the lower radial fluid dynamic bearing portion 39 is provided. As indicated by the arrow, the agent 33 is directed toward the inner circumferential side of the radial communication path 54 provided in the lower portion of the shaft 12, and then the upper shaft direction communication path 51 provided in the shaft 12 is moved upward. Furthermore, it circulates in a radial direction communication passage 52 provided at an intermediate portion in the shaft 12 so as to flow toward the outer peripheral side and return to the lower radial fluid dynamic pressure bearing portion 39. In this case, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and the upper ring-shaped thrust plate 34B The pair of thrust fluid dynamic bearing portions 40 ′ and 41 ′ formed on the upper and lower surfaces are not interposed.

  Further, as shown in FIG. 15E, when the occurrence of each dynamic pressure value is c <d and a = b, the lubrication that has exited through the lower radial fluid dynamic bearing portion 39 is provided. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 15D described above, the other fluid dynamic bearing portions 38, 40 ′, 41 ′ are not interposed here either.

  Therefore, in the example of FIGS. 15B to 15E, the lubricant 33 that has exited here through one radial fluid dynamic pressure bearing portion 38 (or 39) is transferred to the other radial fluid dynamic pressure bearing portion 39 ( Or 38) and can be circulated without the pair of thrust fluid dynamic bearing portions 40 'and 41' formed on the upper and lower surfaces of the upper ring-shaped thrust plate 34B. The agent 33 can be returned.

  Further, FIGS. 15 (F) and 15 (G) show the circulation path of the lubricant 33 by the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39. FIG.

  As shown in FIG. 15F, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A> B), the pair of radial fluid dynamic pressure bearings The lubricating oil 33 passing through the portions 38 and 39 is directed to the radial communication path 54 provided in the lower part of the shaft 12 toward the inner peripheral side as indicated by an arrow, and thereafter, the long oil provided in the shaft 12 is used. The shaft direction communication path 51 flows upward, and further flows in the radial direction communication path 53 provided in the upper portion of the shaft 12 toward the outer peripheral side so as to return to the pair of radial fluid dynamic pressure bearing portions 38 and 39. It circulates to.

  As shown in FIG. 15G, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A <B), the pair of radial fluid dynamics The lubricating oil 33 passing through the pressure bearing portions 38 and 39 flows in the reverse direction with respect to FIG.

  Next, the operation of the pair of thrust fluid dynamic bearing portions 40 ′ and 41 ′ in the fluid dynamic bearing 30 </ b> E that is a main part of the fifth embodiment will be described with reference to FIG. 16.

  As shown in FIGS. 16A and 16B, a pair of thrust fluid dynamic bearing portions 40 ′ (e, f), 41 ′ (g, h) When a slight difference (dynamic pressure difference) occurs in the dynamic pressure values e to h generated by the thrust fluid dynamic pressure grooves 40e, 40f, 41g, and 41h, the lubricant 33 has a dynamic pressure value corresponding to the dynamic pressure difference. Since the flow flows from the high direction to the low direction, it is necessary to circulate the lubricant 33 in order to compensate for the shortage of the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in the fifth embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 16C, in each of the dynamic pressure values e to h described above, the generation of the dynamic pressure values is e> f, g = In the case of h, the lubricant 33 that has exited through the upper thrust fluid dynamic pressure bearing portion 40 'passes through the recess 34d formed on the inner peripheral surface of the ring-shaped thrust plate 34B as indicated by the arrow. After that, it flows in the radial direction communication passage 45 provided in the ring-shaped thrust plate 34B toward the outer peripheral side, and further flows in the outer peripheral gap 47 of the ring-shaped thrust plate 34B upward. It circulates back to the upper thrust fluid dynamic pressure bearing 40 '. In this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 ′ disposed below the upper thrust fluid dynamic pressure bearing portion 40 ′, and a pair of radial fluid dynamic pressures. The bearings 38 and 39 are not interposed.

  In addition, as shown in FIG. 16D, when the generation of each dynamic pressure value is e <f, g = h, the lubrication exiting here through the upper thrust fluid dynamic pressure bearing portion 40 ′. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 16C, the fluid dynamic pressure bearing portions 38, 39, and 41 ′ are not interposed here.

  Further, as shown in FIG. 16E, when the generation of each dynamic pressure value is g> h and e = f, it exits through the lower thrust fluid dynamic bearing portion 41 ′. The lubricant 33 flows upward in the through recess 34d formed on the inner peripheral surface of the ring-shaped thrust plate 34B as indicated by an arrow, and thereafter, the radial communication path 45 provided in the ring-shaped thrust plate 34B. Is further circulated so as to flow downward in the outer circumferential clearance 47 of the ring-shaped thrust plate 34B and return to the lower thrust fluid dynamic bearing portion 41 ′. In this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 ′ disposed above the lower thrust fluid dynamic pressure bearing portion 41 ′, and a pair of radial fluid dynamic pressures. The bearings 38 and 39 are not interposed.

  Further, as shown in FIG. 16F, when the generation of each dynamic pressure value is g <h and e = f, it exits through the lower thrust fluid dynamic pressure bearing portion 41 ′. Since the lubricant 33 circulates in a direction opposite to that shown in FIG. 16 (E), it does not pass through the other fluid dynamic pressure bearing portions 38, 39, 40 ′.

  Accordingly, in the example of FIGS. 16C to 16F, the lubricant 33 that has exited here through one thrust fluid dynamic pressure bearing portion 40 ′ (or 41 ′) is transferred to the other thrust fluid dynamic pressure bearing portion. Since it can circulate without going through 41 '(or 40') and can circulate without going through a pair of radial fluid dynamic bearing parts 38 and 39, lubricant 33 can be returned in an appropriate amount.

FIGS. 17A to 17G are diagrams schematically illustrating the operation of a pair of radial fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are essential portions of the sixth embodiment,
FIGS. 18A to 18D are diagrams schematically showing the operation of a pair of thrust fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are the main portions of the sixth embodiment.

  In the fluid dynamic pressure bearing motor 10F (not shown) of the sixth embodiment according to the present invention, as shown in FIG. 17A, the fluid dynamic pressure bearing 30F, which is the main part of the sixth embodiment, has an outer periphery of the shaft 12. A pair of radial fluid dynamic pressure bearing portions 38, 39 provided with a predetermined axial length at a distance along the shaft direction on either side between the surface and the inner peripheral surface of the inner sleeve 32 Each of the radial fluid dynamic pressure grooves and at least one or more long shaft direction communication paths (vertical communication paths) provided along the shaft direction on either side between the outer sleeve 31 and the inner sleeve 32 43, an inner sleeve 32 provided at an intermediate portion in the shaft direction, one end communicating with the pair of radial fluid dynamic pressure bearing portions 38 and 39 and the other end communicating with the intermediate portion of the shaft direction communication passage 43. It is the same for Al direction communicating channel (Yokoren passage) 44 Example described Togasaki 1,3.

  On the other hand, different points from the first and third embodiments will be described. In the fluid dynamic pressure bearing 30F, which is the main part of the sixth embodiment, the ring described above with reference to FIG. Only the cylindrical thrust plate 34B is fixed, and the ring-shaped thrust plate is not fixed to the lower portion of the shaft 12. Along with this, by forming each thrust fluid dynamic pressure groove by herringbone or a Rayleigh step on the upper and lower surfaces (both sides) of the upper ring-shaped thrust plate 34B, the upper ring-shaped counter plate 36 and the upper ring-shaped thrust plate 34B An upper thrust fluid dynamic pressure bearing portion 40 ′ is provided between the ring-shaped thrust plate 34 B and the lower thrust fluid dynamic pressure between the upper ring-shaped thrust plate 34 B and the upper end portion of the inner sleeve 32. The point that the bearing portion 41 ′ is provided is the same as in the fifth embodiment.

  In addition, a radial communication path (lateral communication path) 45 is provided in the upper ring-shaped thrust plate 34B, and a through recess formed in one end side of the radial communication path 45 on the inner peripheral surface of the ring-shaped thrust plate 34B. The upper radial fluid dynamic pressure bearing portion 38 is connected to an upper portion located above the radial fluid dynamic pressure bearing portion 38 via the upper end 34d, and the other end side is connected to the ring-shaped thrust plate 34B via an outer peripheral gap 47. It communicates with the upper part of the shaft direction communication passage 43. Further, a radial communication passage (lateral communication passage) 57 is provided at a lower portion in the inner sleeve 32, and one end side of the radial communication passage 57 is on the radial fluid dynamic pressure bearing portion 39 side on the lower side. The other end side communicates with a lower part of the shaft direction communication path 43 and communicates with a lower part located below the hydrodynamic bearing portion 39.

  Here, operation | movement of a pair of radial fluid dynamic pressure bearing parts 38 and 39 among the fluid dynamic pressure bearings 30F used as the principal part of Example 6 is demonstrated using FIG.

  As shown in FIG. 17A, in the sixth embodiment, as in the first to fifth embodiments, a slight difference (dynamic pressure difference) between the dynamic pressure values a to d generated by the pair of radial fluid dynamic pressure bearing portions 38 and 39 is obtained. ) Occurs, the lubricant 33 flows in the direction from the high dynamic pressure value to the low direction according to the dynamic pressure difference. Therefore, the lubricant 33 is circulated to compensate for the insufficient amount of the lubricant 33, and an appropriate amount is obtained. It is necessary to return the lubricant 33.

  Therefore, in the sixth embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 17B, the generation of each dynamic pressure value is a> b, c = In the case of d, the lubricant 33 that has exited through the upper radial fluid dynamic pressure bearing portion 38 passes through the radial communication path 44 provided at the intermediate portion in the inner sleeve 32 as indicated by an arrow. It goes to the outer peripheral side, and then flows upward through the long shaft direction communication path 43 and the outer peripheral clearance 47 of the upper ring-shaped thrust plate 34B, and further, the radial direction communication path 45 in the ring-shaped thrust plate 34B. Is directed to the inner peripheral side, and then flows downward through a through recess 34d formed on the inner peripheral surface of the ring-shaped thrust plate 34B so as to return to the upper radial fluid dynamic bearing portion 38. In this case, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and also on the upper ring-shaped thrust plate 34B. The pair of thrust fluid dynamic pressure bearing portions 40 'and 41' formed on the lower surface is not interposed.

  In addition, as shown in FIG. 17C, when the generation of each dynamic pressure value is a <b and c = d, the lubricant that has exited here through the upper radial fluid dynamic bearing portion 38. Since 33 flows and circulates in the opposite direction with respect to FIG. 17B, it does not pass through the other fluid dynamic pressure bearing portions 39, 40 ′, 41 ′.

  Further, as shown in FIG. 17D, when the generation of each dynamic pressure value is c> d and a = b, the lubrication that exits here through the lower radial fluid dynamic bearing portion 39. As indicated by the arrow, the agent 33 moves to the outer peripheral side through the radial communication path 57 provided in the lower part of the inner sleeve 32, and then flows upward through the long shaft communication path 43. Then, it circulates so as to flow in the radial direction communication passage 44 provided at the intermediate portion in the inner sleeve 32 toward the inner peripheral side and to return to the lower radial fluid dynamic pressure bearing portion 39. In this case, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and the upper ring-shaped thrust plate 34B The pair of thrust fluid dynamic bearing portions 40 ′ and 41 ′ formed on the upper and lower surfaces are not interposed.

  Further, as shown in FIG. 17E, when the generation of each dynamic pressure value is c <d and a = b, the lubrication exiting through the lower radial fluid dynamic bearing portion 39 is provided. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 17D described above, the other fluid dynamic pressure bearing portions 38, 40 ′, 41 ′ are not interposed here either.

  Accordingly, in the example of FIGS. 17B to 17E, the lubricant 33 that has exited here through one radial fluid dynamic pressure bearing portion 38 (or 39) is transferred to the other radial fluid dynamic pressure bearing portion 39 ( Or 38) and can be circulated without the pair of thrust fluid dynamic bearing portions 40 'and 41' formed on the upper and lower surfaces of the upper ring-shaped thrust plate 34B. The agent 33 can be returned.

  Further, FIGS. 17 (F) and 17 (G) show the circulation path of the lubricant 33 by the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39. FIG.

  As shown in FIG. 17 (F), when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A> B), the pair of radial fluid dynamic pressure bearings The lubricating oil 33 passing through the portions 38 and 39 is directed toward the outer peripheral side through the radial direction communication passage 57 provided at the lower portion in the inner sleeve 32 as indicated by the arrow. The inner circumferential surface of the ring-shaped thrust plate 34B flows upward through the outer circumferential clearance 47 of the upper ring-shaped thrust plate 34B, and further travels toward the inner circumferential side of the radial communication path 45 in the ring-shaped thrust plate 34B. It circulates in such a way that it flows downward through the through recess 34d and returns to the pair of radial fluid dynamic bearing portions 38, 39.

  In addition, as shown in FIG. 17G, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A <B), the pair of radial fluid dynamics The lubricating oil 33 passing through the pressure bearing portions 38 and 39 flows in the reverse direction with respect to FIG.

  Next, operations of the pair of thrust fluid dynamic pressure bearing portions 40 ′ and 41 ′ in the fluid dynamic pressure bearing 30 </ b> F that is a main part of the sixth embodiment will be described with reference to FIG. 18.

  As shown in FIGS. 18A to 18D, in Example 6, a pair of thrust fluid dynamic pressure bearing portions 40 ′ (e, f), 41 ′ formed on the upper and lower surfaces of the upper ring-shaped thrust plate 34B. When a slight difference (dynamic pressure difference) occurs in the dynamic pressure values e to h generated by (g, h), the lubricant 33 flows from a high pressure value toward a low direction according to the dynamic pressure difference. In order to compensate for the shortage of the lubricant 33, it is necessary to circulate the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in Example 6, when the inner sleeve 32 side rotates, as shown in FIG. 18A, in each of the dynamic pressure values e to h described above, the generation of the dynamic pressure values is e> f, g = In the case of h, the lubricant 33 exiting here through the upper thrust fluid dynamic pressure bearing portion 40 'passes through the inner peripheral surface of the upper ring-shaped thrust plate 34B as shown by the arrow. The concave portion 34d flows downward, and thereafter, the radial communication path 45 in the ring-shaped thrust plate 34B is directed to the outer peripheral side, and further, the outer peripheral clearance 47 of the ring-shaped thrust plate 34B is flowed upward to enter the upper side. Circulation returns to the thrust fluid dynamic bearing 40 '. In this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 ′ disposed below the upper thrust fluid dynamic pressure bearing portion 40 ′, and a pair of radial fluid dynamic pressures. The bearings 38 and 39 are not interposed.

  Further, as shown in FIG. 18B, when the generation of each dynamic pressure value is e <f, g = h, the lubrication that has exited here through the upper thrust fluid dynamic pressure bearing portion 40 ′. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 18A, it does not pass through the other fluid dynamic pressure bearing portions 38, 39, 41 ′.

  Further, as shown in FIG. 18C, when the generation of each dynamic pressure value is g> h and e = f, it exits through the lower thrust fluid dynamic bearing portion 41 ′. The lubricant 33 flows upward through a through recess 34d formed in the inner peripheral surface of the upper ring-shaped thrust plate 34B as indicated by an arrow, and thereafter, the radial communication path 45 in the ring-shaped thrust plate 34B. Is further circulated so as to return to the lower thrust fluid dynamic pressure bearing portion 41 ′ by flowing downward through the outer peripheral clearance 47 of the ring-shaped thrust plate 34B. In this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 ′ disposed above the lower thrust fluid dynamic pressure bearing portion 41 ′, and a pair of radial fluid dynamic pressures. The bearings 38 and 39 are not interposed.

  Further, as shown in FIG. 18D, when the generation of each dynamic pressure value is g <h and e = f, it exits through the lower thrust fluid dynamic bearing portion 41 ′. Since the lubricant 33 circulates in the opposite direction with respect to FIG. 18C, the lubricant 33 does not pass through the other fluid dynamic pressure bearing portions 38, 39, 40 ′.

  Accordingly, in the example of FIGS. 18A to 18D, the lubricant 33 that has exited here through one thrust fluid dynamic pressure bearing portion 40 ′ (or 41 ′) becomes the other thrust fluid dynamic pressure bearing portion. Since it can circulate without going through 41 '(or 40') and can circulate without going through a pair of radial fluid dynamic bearing parts 38 and 39, lubricant 33 can be returned in an appropriate amount.

19 (A) to 19 (G) are diagrams schematically illustrating the operation of a pair of radial fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are essential portions of the seventh embodiment,
FIGS. 20A to 20D are diagrams schematically illustrating the operation of a pair of thrust fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are the main portions of the seventh embodiment.

  In the fluid dynamic bearing motor 10G (not shown) of the seventh embodiment according to the present invention, as shown in FIG. 19A, the fluid dynamic bearing 30G, which is the main part of the seventh embodiment, has an outer periphery of the shaft 12. A pair of radial fluid dynamic pressure bearing portions 38 provided with a predetermined axial length and spaced along the shaft direction on either side between the surface and the inner peripheral surface of the inner sleeve 32; Each of the 39 radial fluid dynamic pressure grooves is the same as in the first to sixth embodiments described above, and a long shaft direction communication path (longitudinal communication path) provided in the shaft 12 along the shaft direction. ) 51, a radial direction communication path (lateral communication path) 52 provided in an intermediate portion in the shaft direction in the shaft 12, and a pair of radial direction communication paths (horizontal communication paths) provided in upper and lower portions in the shaft direction in the shaft 12. Communication path) 53, 4 is the same for Example 2, 4 and 5 as described Togasaki. At this time, the upper portion of the long shaft direction communication path (longitudinal communication path) 51 provided along the shaft direction in the shaft 12 evaporates the lubricant 33 as in the second, fourth, and fifth embodiments. It is closed by a closing plug 55 made of an elastic member for prevention.

  On the other hand, different points from the first, second, fourth, and fifth embodiments will be described. In the fluid dynamic pressure bearing 30G, which is a main part of the seventh embodiment, FIG. Only the ring-shaped thrust plate 34 </ b> C described above is fixed, and the ring-shaped thrust plate is not fixed to the lower portion of the shaft 12. Along with this, by forming each thrust fluid dynamic pressure groove by herringbone or a Rayleigh step on the upper and lower surfaces (both sides) of the upper ring-shaped thrust plate 34C, the upper ring-shaped counter plate 36 and the upper ring-shaped thrust plate 34C An upper thrust fluid dynamic pressure bearing portion 40 ′ is provided between the ring-shaped thrust plate 34 C and the lower thrust fluid dynamic pressure between the upper ring-shaped thrust plate 34 C and the upper end portion of the inner sleeve 32. A bearing portion 41 'is provided.

  Further, an inner circumferential gap 32 d is formed between the upper portion of the inner sleeve 32 and the shaft 12, and the inner circumferential gap 32 d communicates with a radial direction communication path 53 provided in the upper portion of the shaft 12. . In addition, a radial direction communication path (lateral communication path) 56 is provided in an upper portion of the inner sleeve 32 so as to communicate with the inner peripheral gap 32 d, and the other end side of the radial direction communication path 56 is an upper portion of the inner sleeve 32. It communicates with an outer peripheral gap 58 provided at the outer peripheral portion.

  Further, an inner circumferential clearance 36c is formed between the upper ring-shaped counter plate 36 and the shaft 12, and the radial communication path 36d and the shaft communication path 36e are orthogonal to each other so as to communicate with the inner clearance 36c. The inner circumferential clearance 36 c communicates with a through recess 34 e formed on the inner circumferential surface of the ring-shaped thrust plate 34 C, and the shaft direction communication path 36 e communicates with an outer circumferential clearance 47 of the ring-shaped counter plate 36.

  Here, operation | movement of a pair of radial fluid dynamic pressure bearing parts 38 and 39 among the fluid dynamic pressure bearings 30G used as the principal part of Example 7 is demonstrated using FIG.

  As shown in FIG. 19A, in the seventh embodiment, as in the first to sixth embodiments, a slight difference (dynamic pressure difference) between the dynamic pressure values a to d generated by the pair of radial fluid dynamic pressure bearing portions 38 and 39 is obtained. ) Occurs, the lubricant 33 flows in the direction from the high dynamic pressure value to the low direction according to the dynamic pressure difference. Therefore, the lubricant 33 is circulated to compensate for the insufficient amount of the lubricant 33, and an appropriate amount is obtained. It is necessary to return the lubricant 33.

  Therefore, in the seventh embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 19B, the generation of each dynamic pressure value is a> b, c = In the case of d, the lubricant 33 exiting through the upper radial fluid dynamic pressure bearing portion 38 enters the radial communication passage 52 provided at the intermediate portion in the shaft 12 as indicated by an arrow. It goes to the circumferential side, and then flows upward in the long shaft direction communication passage 51 provided in the shaft 12, and further, the radial direction communication passage 53 provided in the upper portion in the shaft 12 toward the outer periphery side. And circulates back to the upper radial fluid dynamic bearing portion 38. In this case, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and also on the upper ring-shaped thrust plate 34C. The pair of thrust fluid dynamic pressure bearing portions 40 'and 41' formed on the lower surface is not interposed.

  Further, as shown in FIG. 19C, when the generation of each dynamic pressure value is a <b and c = d, the lubricant that has exited here through the upper radial fluid dynamic bearing portion 38. Since 33 circulates in a direction opposite to that shown in FIG. 19B, the fluid dynamic pressure bearing portions 39, 40 ′, and 41 ′ are not interposed here.

  Further, as shown in FIG. 19D, when the generation of each dynamic pressure value is c> d and a = b, the lubrication that exits here through the lower radial fluid dynamic bearing portion 39. As indicated by the arrow, the agent 33 is directed toward the inner circumferential side of the radial communication path 54 provided in the lower portion of the shaft 12, and then the upper shaft direction communication path 51 provided in the shaft 12 is moved upward. Furthermore, it circulates in a radial direction communication passage 52 provided at an intermediate portion in the shaft 12 so as to flow toward the outer peripheral side and return to the lower radial fluid dynamic pressure bearing portion 39. In this case, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and the upper ring-shaped thrust plate 34C. The pair of thrust fluid dynamic bearing portions 40 ′ and 41 ′ formed on the upper and lower surfaces are not interposed.

  Further, as shown in FIG. 19 (E), when the occurrence of each dynamic pressure value is c <d and a = b, the lubrication that exits here through the lower radial fluid dynamic bearing portion 39. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 19D described above, the other fluid dynamic pressure bearing portions 38, 40 ′, 41 ′ are not interposed here either.

  Accordingly, in the example of FIGS. 19B to 19E, the lubricant 33 that has exited here through one radial fluid dynamic pressure bearing portion 38 (or 39) is transferred to the other radial fluid dynamic pressure bearing portion 39 ( Or, it can circulate without going through 38) and circulate without going through the pair of thrust fluid dynamic pressure bearing portions 40 ', 41' formed on the upper and lower surfaces of the upper ring-shaped thrust plate 34C.

  Further, FIGS. 19 (F) and 19 (G) show the circulation path of the lubricant 33 by the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39. FIG.

  As shown in FIG. 19F, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A> B), the pair of radial fluid dynamic pressure bearings The lubricating oil 33 passing through the portions 38 and 39 is directed to the radial communication path 54 provided in the lower part of the shaft 12 toward the inner peripheral side as indicated by an arrow, and thereafter, the long oil provided in the shaft 12 is used. The shaft direction communication path 51 flows upward, and further flows in the radial direction communication path 53 provided in the upper portion of the shaft 12 toward the outer peripheral side so as to return to the pair of radial fluid dynamic pressure bearing portions 38 and 39. It circulates to.

  Further, as shown in FIG. 19G, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A <B), the pair of radial fluid dynamics The lubricating oil 33 passing through the pressure bearing portions 38 and 39 flows in the reverse direction with respect to FIG.

  Next, operations of the pair of thrust fluid dynamic pressure bearing portions 40 ′ and 41 ′ in the fluid dynamic pressure bearing 30 </ b> G that is a main part of the seventh embodiment will be described with reference to FIG. 20.

  As shown in FIGS. 20A to 20D, a pair of thrust fluid dynamic pressure bearing portions 40 ′ (e, f), 41 ′ (g, h) formed on the upper and lower surfaces of the upper ring-shaped thrust plate 34C. When there is a slight difference (dynamic pressure difference) between the dynamic pressure values e to h generated by the above, the lubricant 33 flows from the high pressure value toward the low direction according to the dynamic pressure difference, so the lack of the lubricant 33 In order to make up the amount, it is necessary to circulate the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in the seventh embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 20A, in each of the dynamic pressure values e to h described above, the generation of the dynamic pressure values is e> f, g = In the case of h, the lubricant 33 that has exited through the upper thrust fluid dynamic pressure bearing portion 40 ′ is formed on the inner peripheral surface of the upper ring-shaped counter plate 36 as indicated by an arrow. Flows upward in the circumferential gap 36c, then flows in the radial direction communication path 36d provided in the ring-shaped counter plate 36 toward the outer peripheral side, and further in the shaft direction provided in the upper ring-shaped counter plate 36. It circulates so as to flow downward in the communication passage 36e and return to the upper thrust fluid dynamic bearing portion 40 ′. In this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 ′ disposed below the upper thrust fluid dynamic pressure bearing portion 40 ′, and a pair of radial fluid dynamic pressures. The bearings 38 and 39 are not interposed.

  Further, as shown in FIG. 20B, when the generation of each dynamic pressure value is e <f, g = h, the lubrication that has exited here through the upper thrust fluid dynamic pressure bearing portion 40 ′. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 20A, the fluid dynamic pressure bearing portions 38, 39, and 41 ′ are not interposed here.

  Further, as shown in FIG. 20C, when the generation of each dynamic pressure value is g> h and e = f, it exits through the lower thrust fluid dynamic bearing portion 41 ′. The lubricant 33 flows downward through an inner peripheral gap 32d formed on the upper inner peripheral surface of the inner sleeve 32 as indicated by an arrow, and thereafter, a radial communication path provided at an upper portion in the inner sleeve 32. 56 flows toward the outer peripheral side, and further circulates so as to flow upward through an outer peripheral clearance 58 provided at the upper outer peripheral portion of the inner sleeve 32 and return to the lower thrust fluid dynamic bearing portion 41 ′. In this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 ′ disposed above the lower thrust fluid dynamic pressure bearing portion 41 ′, and a pair of radial fluid dynamic pressures. The bearings 38 and 39 are not interposed.

  Further, as shown in FIG. 20D, when the generation of each dynamic pressure value is g <h and e = f, it exits through the lower thrust fluid dynamic bearing portion 41 ′. Since the lubricant 33 flows and circulates in the opposite direction with respect to FIG. 20C, the fluid dynamic pressure bearing portions 38, 39, and 40 ′ are not interposed here.

  Accordingly, in the example of FIGS. 20A to 20D, the lubricant 33 that has exited here through one thrust fluid dynamic pressure bearing portion 40 ′ (or 41 ′) is transferred to the other thrust fluid dynamic pressure bearing portion. Since it can circulate without going through 41 '(or 40') and can circulate without going through a pair of radial fluid dynamic bearing parts 38 and 39, lubricant 33 can be returned in an appropriate amount.

FIGS. 21 (A) to (G) are diagrams schematically illustrating the operation of a pair of radial fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are essential portions of the eighth embodiment,
22A to 22D are diagrams schematically illustrating the operation of a pair of thrust fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are the main portions of the eighth embodiment.

  In the fluid dynamic pressure bearing motor 10H (not shown) of the eighth embodiment according to the present invention, as shown in FIG. 21A, the fluid dynamic pressure bearing 30H, which is the main part of the eighth embodiment, has an outer periphery of the shaft 12. A pair of radial fluid dynamic pressure bearing portions 38 each having a predetermined axial length with an interval along the shaft direction on either side between the surface and the inner peripheral surface of the inner sleeve 32. , 39, and a long shaft direction communication path (longitudinal communication path) 43 provided along the shaft direction on either side between the outer sleeve 31 and the inner sleeve 32; The inner sleeve 32 is provided in the radial direction at an intermediate portion in the shaft direction, one end communicates between the pair of radial fluid dynamic bearing portions 38 and 39, and the other end communicates with the intermediate portion of the shaft direction communication passage 43. It is the same for the radial direction communicating channel (Yokoren passage) 44 Example described Togasaki 1,3,6 to.

  In addition, a pair of radial communication paths (lateral communication paths) 56 and 57 are provided in the upper and lower portions of the inner sleeve 32 in the shaft direction, and one end side of the pair of radial communication paths 56 and 57 is a pair of radials. The fluid dynamic pressure bearing portions 38 and 39 communicate with the upper and lower portions positioned above and below the pair of radial fluid dynamic pressure bearing portions 38 and 39 and the other ends communicate with the upper and lower portions of the shaft direction communication passage 43. This is the same as the third embodiment.

  Further, only the ring-shaped thrust plate 34C described above with reference to FIG. 3C is fixed to the upper portion of the shaft 12, and the ring-shaped thrust plate is not fixed to the lower portion of the shaft 12. Along with this, by forming each thrust fluid dynamic pressure groove by herringbone or a Rayleigh step on the upper and lower surfaces (both sides) of the upper ring-shaped thrust plate 34C, the upper ring-shaped counter plate 36 and the upper ring-shaped thrust plate 34C An upper thrust fluid dynamic pressure bearing portion 40 ′ is provided between the ring-shaped thrust plate 34 C and the lower thrust fluid dynamic pressure between the upper ring-shaped thrust plate 34 C and the upper end portion of the inner sleeve 32. The point that the bearing portion 41 ′ is provided is the same as that of the seventh embodiment.

  Further, an inner circumferential clearance 36c is formed between the upper ring-shaped counter plate 36 and the shaft 12, and the radial communication path 36d and the shaft communication path 36e are orthogonal to each other so as to communicate with the inner clearance 36c. The inner circumferential clearance 36c communicates with a through recess 34e formed on the inner circumferential surface of the ring-shaped thrust plate 34C, and the shaft direction communication passage 36e communicates with an outer circumferential clearance 47 of the ring-shaped counter plate 36. Is the same as in Example 7.

  Here, an operation of the pair of radial fluid dynamic pressure bearing portions 38 and 39 in the fluid dynamic pressure bearing 30H which is a main portion of the eighth embodiment will be described with reference to FIG.

  As shown in FIG. 21A, in the eighth embodiment as well, in the same manner as in the first to seventh embodiments, a slight difference (dynamic pressure difference) between the dynamic pressure values a to d generated by the pair of radial fluid dynamic pressure bearing portions 38 and 39 is obtained. ) Occurs, the lubricant 33 flows in the direction from the high dynamic pressure value to the low direction according to the dynamic pressure difference. Therefore, the lubricant 33 is circulated to compensate for the insufficient amount of the lubricant 33, and an appropriate amount is obtained. It is necessary to return the lubricant 33.

  Therefore, in the eighth embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 21B, in each of the above-described dynamic pressure values a to d, the generation of the dynamic pressure values is a> b, c = In the case of d, the lubricant 33 that has exited through the upper radial fluid dynamic pressure bearing portion 38 passes through the radial communication path 44 provided at the intermediate portion in the inner sleeve 32 as indicated by an arrow. It goes to the outer peripheral side, and then flows upward in the long shaft direction communication path 43, and further flows in the radial direction communication path 56 provided in the upper part in the inner sleeve 32 toward the inner peripheral side and moves upward. It circulates back to the radial fluid dynamic pressure bearing portion 38. In this case, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and also on the upper ring-shaped thrust plate 34C. The pair of thrust fluid dynamic pressure bearing portions 40 'and 41' formed on the lower surface is not interposed.

  In addition, as shown in FIG. 21C, when the generation of each dynamic pressure value is a <b and c = d, the lubricant that has exited through the upper radial fluid dynamic bearing portion 38. Since 33 circulates in a direction opposite to that shown in FIG. 21B, the fluid dynamic pressure bearing portions 39, 40 ′ and 41 ′ are not interposed here.

  Further, as shown in FIG. 21D, when the generation of each dynamic pressure value is c> d and a = b, the lubrication that exits through the lower radial fluid dynamic bearing portion 39 is provided. As indicated by the arrow, the agent 33 moves to the outer peripheral side through the radial communication path 57 provided in the lower part of the inner sleeve 32, and then flows upward through the long shaft communication path 43. Then, it circulates so as to flow in the radial direction communication passage 44 provided at the intermediate portion in the inner sleeve 32 toward the inner peripheral side and to return to the lower radial fluid dynamic pressure bearing portion 39. In this case, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and the upper ring-shaped thrust plate 34C. The pair of thrust fluid dynamic bearing portions 40 ′ and 41 ′ formed on the upper and lower surfaces are not interposed.

  Further, as shown in FIG. 21E, when the generation of each dynamic pressure value is c <d and a = b, the lubrication that has exited through the lower radial fluid dynamic bearing portion 39 is provided. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 21 (D), the fluid dynamic pressure bearing portions 38, 40 ′, and 41 ′ are not interposed here.

  Accordingly, in the example of FIGS. 21B to 21E, the lubricant 33 that has exited here through one radial fluid dynamic pressure bearing portion 38 (or 39) is transferred to the other radial fluid dynamic pressure bearing portion 39 ( Or, it can circulate without going through 38) and circulate without going through the pair of thrust fluid dynamic pressure bearing portions 40 ', 41' formed on the upper and lower surfaces of the upper ring-shaped thrust plate 34C.

  Further, FIGS. 21 (F) and 21 (G) show the circulation path of the lubricant 33 by the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39. FIG.

  As shown in FIG. 21F, when the dynamic pressures A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A> B), the pair of radial fluid dynamic pressure bearing portions. As indicated by the arrows, the lubricating oil 33 passing through 38 and 39 is directed toward the outer peripheral side through the radial communication path 57 provided in the lower portion of the inner sleeve 32, and thereafter, the long shaft direction communication path 43 is moved upward. Furthermore, it circulates so as to flow toward the inner peripheral side through the radial communication path 56 provided in the upper portion of the inner sleeve 32 and return to the pair of radial fluid dynamic pressure bearing portions 38 and 39.

  In addition, as shown in FIG. 21G, when the dynamic pressures A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A <B), the pair of radial fluid dynamic pressures. The lubricating oil 33 passing through the bearing portions 38 and 39 flows in the reverse direction with respect to FIG.

  Next, operations of the pair of thrust fluid dynamic pressure bearing portions 40 ′ and 41 ′ in the fluid dynamic pressure bearing 30 </ b> H that is a main part of the eighth embodiment will be described with reference to FIG. 22.

  As shown in FIGS. 22A to 22D, a pair of thrust fluid dynamic pressure bearing portions 40 ′ (e, f), 41 ′ (g, h) formed on the upper and lower surfaces of the upper ring-shaped thrust plate 34C. When there is a slight difference (dynamic pressure difference) between the dynamic pressure values e to h generated by the above, the lubricant 33 flows from the high pressure value toward the low direction according to the dynamic pressure difference, so the lack of the lubricant 33 In order to make up the amount, it is necessary to circulate the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in the eighth embodiment, when the inner sleeve 32 side is rotated, as shown in FIG. 22A, in each of the dynamic pressure values e to h described above, the generation of the dynamic pressure values is e> f, g = In the case of h, the lubricant 33 that has exited through the upper thrust fluid dynamic pressure bearing portion 40 ′ is formed on the inner peripheral surface of the upper ring-shaped counter plate 36 as indicated by an arrow. Flows upward in the circumferential gap 36c, then flows in the radial direction communication path 36d provided in the ring-shaped counter plate 36 toward the outer peripheral side, and further in the shaft direction provided in the upper ring-shaped counter plate 36. It circulates so as to flow downward in the communication passage 36e and return to the upper thrust fluid dynamic bearing portion 40 ′. In this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 ′ disposed below the upper thrust fluid dynamic pressure bearing portion 40 ′, and a pair of radial fluid dynamic pressures. The bearings 38 and 39 are not interposed.

  Further, as shown in FIG. 22B, when the generation of each dynamic pressure value is e <f, g = h, the lubrication that has exited through the upper thrust fluid dynamic pressure bearing portion 40 ′. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 22 (A), it does not go through the other fluid dynamic bearing portions 38, 39, 41 ′.

  Further, as shown in FIG. 22C, when the generation of each dynamic pressure value is g> h and e = f, it exits through the lower thrust fluid dynamic bearing portion 41 ′. As indicated by the arrow, the lubricant 33 flows downward in a corner portion 32c formed on the inner periphery of the inner sleeve 32, and then passes through a radial communication path 56 provided in an upper portion of the inner sleeve 32. It circulates so as to flow toward the outer peripheral side and further flow upward in the shaft direction communication passage 43 and return to the lower thrust fluid dynamic bearing portion 41 ′. In this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 ′ disposed above the lower thrust fluid dynamic pressure bearing portion 41 ′, and a pair of radial fluid dynamic pressures. The bearings 38 and 39 are not interposed.

  Further, as shown in FIG. 22D, when the generation of each dynamic pressure value is g <h and e = f, it exits through the lower thrust fluid dynamic bearing portion 41 ′. Since the lubricant 33 circulates in the opposite direction with respect to FIG. 22 (C), it does not pass through the other fluid dynamic pressure bearing portions 38, 39, 40 ′.

  Accordingly, in the example of FIGS. 22A to 22D, the lubricant 33 that has exited through one thrust fluid dynamic pressure bearing portion 40 ′ (or 41 ′) is transferred to the other thrust fluid dynamic pressure bearing portion. Since it can circulate without going through 41 '(or 40') and can circulate without going through a pair of radial fluid dynamic bearing parts 38 and 39, lubricant 33 can be returned in an appropriate amount.

FIGS. 23A to 23G are diagrams schematically illustrating the operation of a pair of radial fluid dynamic bearings among the fluid dynamic bearings that are the main part of the ninth embodiment,
FIGS. 24A to 24D are diagrams schematically illustrating the operation of a pair of thrust fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are essential portions of the ninth embodiment.

  In the fluid dynamic bearing motor 10I (not shown) of the ninth embodiment according to the present invention, as shown in FIG. 23 (A), the fluid dynamic bearing 30I which is the main part of the ninth embodiment has a motor base 11 ( The shape of the shaft 12 fixed to FIG. 1) is formed in a stepped columnar shape unlike the first to eighth embodiments, and the shaft 12 is formed with a large diameter portion 12e along the longitudinal direction. In addition, small-diameter portions 12f and 12g smaller in diameter than the large-diameter portion 12e are formed on the upper and lower sides of the large-diameter portion 12e so as to protrude in a short length.

  Accordingly, the pair of ring-shaped thrust plates 34D and 35D described above with reference to FIG. 3D are opposed to the upper and lower ends in the shaft direction of the large-diameter portion 12e formed on the shaft 12, respectively. The outer peripheral surfaces of the pair of ring-shaped thrust plates 34D, 35D are fitted and fixed to the upper and lower inner peripheral surfaces of the inner sleeve 32, and the small diameter portions 12f, 12g formed on the upper and lower sides of the shaft 12 are fixed. The upper and lower pair of ring-shaped counter plates 36 and 37 are greatly different from the first to eighth embodiments described above in that the inner peripheral surfaces are fitted and fixed.

  The fluid dynamic pressure bearing 30I that is the main part of the above-described ninth embodiment is spaced along the shaft direction on either side between the outer peripheral surface of the large-diameter portion 12e of the shaft 12 and the inner peripheral surface of the inner sleeve 32. And each of the radial fluid dynamic pressure grooves of the pair of radial fluid dynamic pressure bearing portions 38 and 39 provided with predetermined lengths in the axial direction and upper and lower ends on the large diameter portion 12e side of the shaft 12. Each of the thrust fluid dynamic pressure grooves of the pair of thrust fluid dynamic pressure bearing portions 40, 41 provided on either side between the lower surface and the upper surface of the ring-shaped thrust plates 34D, 35D, and the shaft 12 A long shaft direction communication passage (vertical communication passage) 51 provided along the shaft direction in the large diameter portion 12e, and an intermediate portion in the shaft direction within the large diameter portion 12e of the shaft 12, with one end side being a shaft Direction communication A radial communication path (lateral communication path) 52 that communicates with the intermediate portion 51 and the other end communicates between the pair of radial fluid dynamic pressure bearing portions 38 and 39, and a radial within the pair of ring-shaped thrust plates 34D and 35D. Each end is communicated with the upper and lower parts of the shaft direction communication passage 51 via the inner circumferential gaps 49 and 50, and each other end is formed on each outer peripheral surface of the pair of ring-shaped thrust plates 34D and 35D. A pair of radial fluid dynamic pressure bearing portions 38, 39 is communicated with an upper and lower portion located above and below the pair of radial fluid dynamic pressure bearing portions 38, 39 via the bottomed recesses 34f, 35f. It consists of passages (horizontal communication passages) 45 and 46.

  In the ninth embodiment, a pair of upper and lower ring-shaped counter plates 36 and 37 are fixed to the small-diameter portions 12f and 12g formed on the upper and lower sides of the shaft 12 that is fixedly installed. Each thrust fluid dynamic pressure groove is formed on the upper and lower surfaces (both sides) of the plates 34D and 35D by herringbone or a ray-lay step.

  Here, operation | movement of a pair of radial fluid dynamic pressure bearing parts 38 and 39 among the fluid dynamic pressure bearings 30I used as the principal part of Example 9 is demonstrated using FIG.

  As shown in FIG. 23A, when a slight difference (dynamic pressure difference) occurs between the dynamic pressure values a to d generated by the pair of radial fluid dynamic pressure bearing portions 38 and 39, the lubricant 33 responds to the dynamic pressure difference. Therefore, in order to compensate for the shortage of the lubricant 33, it is necessary to circulate the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in the ninth embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 23B, in each of the above-described dynamic pressure values a to d, the occurrence of each dynamic pressure value is a> b, c = In the case of d, the lubricant 33 exiting through the upper radial fluid dynamic pressure bearing portion 38 enters the radial communication passage 52 provided at the intermediate portion in the shaft 12 as indicated by an arrow. It goes to the circumferential side, and then flows upward in the long shaft direction communication path 51 provided in the shaft 12 and the inner circumferential gap 49 of the upper ring-shaped thrust plate 34D, and further, the ring-shaped thrust plate 34D. After the radial direction communication passage 45 provided inside is directed to the outer peripheral side, it flows downward through a bottomed recess 34f formed on the outer peripheral surface of the ring-shaped thrust plate 34D and returns to the upper radial fluid dynamic pressure bearing portion 38. Sea urchin circulating. In this case, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and a pair of upper and lower ring thrust plates 34D, The pair of thrust fluid dynamic pressure bearing portions 40 and 41 formed in 35D is not interposed.

  Further, as shown in FIG. 23C, when the generation of each dynamic pressure value is a <b and c = d, the lubricant that has exited here through the upper radial fluid dynamic bearing portion 38. Since 33 circulates in a direction opposite to that shown in FIG. 23B, the fluid dynamic pressure bearing portions 39, 40, and 41 are not interposed here.

  Further, as shown in FIG. 23D, when the generation of each dynamic pressure value is c> d and a = b, the lubrication exiting through the lower radial fluid dynamic bearing portion 39 is provided. The agent 33 flows downward in a bottomed recess 35f formed on the outer peripheral surface of the lower ring-shaped thrust plate 35D as indicated by an arrow, and then the radial communication passage 46 provided in the ring-shaped thrust plate 35D. To the inner circumferential side, and then flows upward through the inner circumferential clearance 50 of the lower ring-shaped thrust plate 35D and the long shaft direction communication path 51 provided in the shaft 12, and further to the shaft 12 It circulates so as to flow toward the outer peripheral side through the radial direction communication passage 52 provided in the intermediate portion and to return to the lower radial fluid dynamic pressure bearing portion 39. In this case, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and a pair of upper and lower ring thrust plates 34D. , 35D, a pair of thrust fluid dynamic pressure bearing portions 40, 41 are not interposed.

  Further, as shown in FIG. 23 (E), when the generation of each dynamic pressure value is c <d and a = b, the lubrication that has exited through the lower radial fluid dynamic bearing portion 39 is provided. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 23D described above, the other fluid dynamic pressure bearing portions 38, 40, and 41 are not interposed here either.

  Accordingly, in the example shown in FIGS. 23B to 23E, the lubricant 33 exiting through the radial fluid dynamic pressure bearing portion 38 (or 39) of the one side is transferred to the other radial fluid dynamic pressure bearing portion 39 ( Or 38) and can be circulated without the pair of thrust fluid dynamic bearing portions 40, 41 formed on the pair of upper and lower ring-shaped thrust plates 34D, 35D. Can be returned.

  Further, FIGS. 23 (F) and 23 (G) show the circulation path of the lubricant 33 by the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39. FIG.

  As shown in FIG. 23F, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A> B), the pair of radial fluid dynamic pressure bearings The lubricating oil 33 passing through the portions 38 and 39 flows downward in the bottomed recess 35f formed on the outer peripheral surface of the lower ring-shaped thrust plate 35D as indicated by the arrow, and then enters the ring-shaped thrust plate 35D. The provided radial direction communication passage 46 is directed to the inner peripheral side, and thereafter, the inner circumferential clearance 50 of the lower ring-shaped thrust plate 35D and the long shaft direction communication passage 51 provided in the shaft 12 and the upper ring shape are provided. After flowing upward through the inner circumferential clearance 49 of the thrust plate 34D, and further toward the outer circumferential side of the radial communication path 45 provided in the ring-shaped thrust plate 34D, the ring-shaped thrust A bottomed recess 34f formed on the outer peripheral surface of the rates 34D flows downward circulated back to the pair of radial fluid dynamic bearing 38 and 39.

  Further, as shown in FIG. 23G, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A <B), the pair of radial fluid dynamics The lubricating oil 33 passing through the pressure bearing portions 38 and 39 flows in the opposite direction to the above FIG. 23 (F) and circulates.

  Next, the operation of the pair of thrust fluid dynamic pressure bearing portions 40 and 41 in the fluid dynamic pressure bearing 30I which is a main part of the ninth embodiment will be described with reference to FIG.

  As shown in FIGS. 24A to 24D, it is generated by a pair of thrust fluid dynamic pressure bearing portions 40 (e, f), 41 (g, h) formed on a pair of upper and lower ring thrust plates 34D, 35D. When a slight difference (dynamic pressure difference) occurs in the dynamic pressure values e to h, the lubricant 33 flows from the high pressure value toward the low direction according to the dynamic pressure difference, and therefore the deficiency of the lubricant 33 is reduced. In order to compensate, it is necessary to circulate the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in the ninth embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 24A, in each of the dynamic pressure values e to h described above, the generation of the dynamic pressure values is e> f, g = In the case of h, the lubricant 33 exiting here through the upper thrust fluid dynamic pressure bearing portion 40 is directed upward through the inner circumferential clearance 49 of the upper ring-shaped thrust plate 34D as indicated by an arrow. After that, the radial flow passage 45 formed in the ring-shaped thrust plate 34D flows toward the outer peripheral side, and further, the bottomed recess 34f formed on the outer peripheral surface of the ring-shaped thrust plate 34D moves downward. It circulates so as to flow back to the upper thrust fluid dynamic bearing portion 40. In this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 disposed below the upper thrust fluid dynamic pressure bearing portion 40, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  Further, as shown in FIG. 24B, when the occurrence of each dynamic pressure value is e <f, g = h, the lubricant that has left here through the upper thrust fluid dynamic pressure bearing portion 40. Since 33 flows and circulates in the opposite direction with respect to FIG. 24A described above, the other fluid dynamic pressure bearing portions 38, 39, and 41 are not interposed here.

  Also, as shown in FIG. 24C, when the generation of each dynamic pressure value is g> h and e = f, the lubrication that has left here through the lower thrust fluid dynamic pressure bearing 41 is used. The agent 33 flows downward through the inner circumferential gap 50 of the lower ring-shaped thrust plate 35D as indicated by an arrow, and thereafter, the radial communication path 46 formed in the lower ring-shaped thrust plate 35D. To the outer peripheral side, and further flows upward through a bottomed recess 35f formed on the outer peripheral surface side of the lower ring-shaped thrust plate 35D so as to return to the lower thrust fluid dynamic pressure bearing portion 41. Circulate. In this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 disposed above the lower thrust fluid dynamic pressure bearing portion 41, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  Further, as shown in FIG. 24D, when the generation of each dynamic pressure value is g <h and e = f, the lubrication that has exited through the lower thrust fluid dynamic pressure bearing 41 is provided. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 24C described above, the other fluid dynamic pressure bearing portions 38, 39, and 40 are not used here either.

  Accordingly, in the example of FIGS. 24A to 24D, the lubricant 33 that has exited here through one thrust fluid dynamic pressure bearing portion 40 (or 41) is transferred to the other thrust fluid dynamic pressure bearing portion 41 ( Alternatively, the lubricant 33 can be circulated without going through 40) and can be circulated without going through the pair of radial fluid dynamic pressure bearing portions 38, 39, so that the lubricant 33 can be returned in an appropriate amount.

FIGS. 25A to 25G are diagrams schematically illustrating the operation of a pair of radial fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are the main portions of the tenth embodiment,
FIGS. 26A to 26D are diagrams schematically illustrating the operation of a pair of thrust fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are the main portions of the tenth embodiment.

  In the fluid dynamic bearing motor 10J (not shown) of the tenth embodiment according to the present invention, as shown in FIG. 25 (A), the fluid dynamic bearing 30J that is the main part of the tenth embodiment has been described above. Similarly to the ninth embodiment, a pair of ring-shaped thrusts described above with reference to FIG. 3 (D) at the upper and lower ends of the large diameter portion 12e formed on the shaft 12 fixed to the motor base 11 (FIG. 1). The plates 34D and 35D are opposed to each other, and the outer peripheral surfaces of the pair of ring-shaped thrust plates 34D and 35D are fitted and fixed to the upper and lower inner peripheral surfaces of the inner sleeve 32, and the shaft 12 The inner peripheral surfaces of a pair of upper and lower ring-shaped counter plates 36 and 37 are fitted and fixed to the small-diameter portions 12f and 12g formed in FIG.

  In the fluid dynamic pressure bearing 30J, which is the main part of the above-described tenth embodiment, the distance between the outer peripheral surface of the large-diameter portion 12e of the shaft 12 and the inner peripheral surface of the inner sleeve 32 is set along the shaft direction on either side. And each of the radial fluid dynamic pressure grooves of the pair of radial fluid dynamic pressure bearing portions 38 and 39 provided with predetermined lengths in the axial direction and upper and lower ends on the large diameter portion 12e side of the shaft 12. Each of the thrust fluid dynamic pressure groove portions of the pair of thrust fluid dynamic pressure bearing portions 40, 41 provided on either side between the lower surface and the lower surface and the upper surface of the pair of ring-shaped thrust plates 34D, 35D, and a pair of rings A pair of radial communication paths (lateral communication paths) 45 and 46 provided in the radial direction in the cylindrical thrust plates 34D and 35D are the same as those of the ninth embodiment described above.

  On the other hand, different points from the ninth embodiment will be described. In the fluid dynamic pressure bearing 30J which is a main part of the tenth embodiment, the long shaft direction communication passage (vertical communication passage) 43 is formed by the outer sleeve 31 and the inner sleeve 32. And a radial communication path (lateral communication path) 44 is provided at an intermediate portion of the inner sleeve 32 in the shaft direction, and one end side is a pair of radial fluids. The fluid pressure bearing portions 38 and 39 communicate with each other and the other end communicates with an intermediate portion of the shaft direction communication passage 43. Further, a pair of radial communication passages (lateral communication passages) 56 and 57 are provided in the upper and lower portions of the inner sleeve 32 in the shaft direction, and one end of each of the pair of radial communication passages 56 and 57 is a pair of rings. Are connected to a pair of radial direction communication passages 45, 46 provided in the cylindrical thrust plates 34 D, 35 D, and the other end side is connected to the upper and lower portions of the shaft direction communication passage 43.

  In the tenth embodiment as well, a pair of upper and lower ring-shaped counter plates 36 and 37 are fixed to the small-diameter portions 12f and 12g formed on the upper and lower sides of the shaft 12 that is fixedly installed. Each thrust fluid dynamic pressure groove is formed on the upper and lower surfaces (both sides) of the plates 34D and 35D by herringbone or a ray-lay step.

  Furthermore, each one end side of a pair of radial direction communication paths 56 and 57 provided in the upper and lower parts in the inner sleeve 32 has a bottomed recess 34f formed on each outer peripheral surface of the pair of upper and lower ring-shaped thrust plates 34A and 35A. The pair of radial fluid dynamic pressure bearing portions 38 and 39 communicates with the upper and lower portions positioned above and below the pair of radial fluid dynamic pressure bearing portions 38 and 39 via 35f.

  Here, operation | movement of a pair of radial fluid dynamic pressure bearing parts 38 and 39 among the fluid dynamic pressure bearings 30J used as the principal part of Example 10 is demonstrated using FIG.

  As shown in FIG. 25 (A), in Example 10 as well as Example 9, there is a slight difference (dynamic pressure difference) between the dynamic pressure values a to d generated by the pair of radial fluid dynamic pressure bearing portions 38 and 39. When this occurs, the lubricant 33 flows from a high dynamic pressure value toward a low pressure according to the dynamic pressure difference. Therefore, the lubricant 33 is circulated to compensate for the insufficient amount of the lubricant 33, and an appropriate amount of lubrication is achieved. It is necessary to return the agent 33.

  Therefore, in the tenth embodiment, when the inner sleeve 32 side is rotated, as shown in FIG. 25 (B), the generation of each dynamic pressure value is a> b, c = In the case of d, the lubricant 33 that has exited through the upper radial fluid dynamic pressure bearing portion 38 passes through the radial communication path 44 provided at the intermediate portion in the inner sleeve 32 as indicated by an arrow. It goes to the outer peripheral side, and then flows upward in a long shaft direction communication path 43 provided between the outer sleeve 31 and the inner sleeve 32, and is further provided in a radial direction provided at an upper portion in the inner sleeve 32. After passing through the communication path 56 toward the inner peripheral side, it flows downward through a bottomed recess 34f formed on the outer peripheral surface of the ring-shaped thrust plate 34D and circulates so as to return to the upper radial fluid dynamic bearing portion 38. That. In this case, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and a pair of upper and lower ring thrust plates 34D, The pair of thrust fluid dynamic pressure bearing portions 40 and 41 formed in 35D is not interposed.

  Further, as shown in FIG. 25C, when the generation of each dynamic pressure value is a <b and c = d, the lubricant that has exited here through the upper radial fluid dynamic bearing portion 38. Since 33 circulates in a direction opposite to that shown in FIG. 25B, the fluid dynamic pressure bearing portions 39, 40, and 41 are not interposed here.

  Further, as shown in FIG. 25D, when the generation of each dynamic pressure value is c> d and a = b, the lubrication that exits here through the lower radial fluid dynamic bearing portion 39. The agent 33 is a radial communication path provided at a lower portion in the inner sleeve 32 after flowing downward through a bottomed recess 35f formed on the outer peripheral surface of the lower ring-shaped thrust plate 35D as indicated by an arrow. 57 is directed to the outer peripheral side, and thereafter flows through the long shaft direction communication path 43 upward, and further flows through the radial direction communication path 44 provided at an intermediate portion in the inner sleeve 32 toward the inner peripheral side. And circulate so as to return to the lower radial fluid dynamic pressure bearing 39. In this case, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and a pair of upper and lower ring thrust plates 34D. , 35D, a pair of thrust fluid dynamic pressure bearing portions 40, 41 are not interposed.

  Further, as shown in FIG. 25E, when the generation of each dynamic pressure value is c <d and a = b, the lubrication that has exited here through the lower radial fluid dynamic pressure bearing portion 39. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 25D described above, the other fluid dynamic pressure bearing portions 38, 40, and 41 are not interposed here.

  Accordingly, in the example of FIGS. 25B to 25E, the lubricant 33 that has exited here through one radial fluid dynamic pressure bearing portion 38 (or 39) is transferred to the other radial fluid dynamic pressure bearing portion 39 ( Or 38) and can be circulated without the pair of thrust fluid dynamic bearing portions 40, 41 formed on the pair of upper and lower ring-shaped thrust plates 34D, 35D. Can be returned.

  Further, FIGS. 25 (F) and 25 (G) show the circulation path of the lubricant 33 by the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39. FIG.

  As shown in FIG. 25 (F), when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A> B), the pair of radial fluid dynamic pressure bearings The lubricating oil 33 passing through the portions 38 and 39 flows downward in the bottomed recess 35f formed on the outer peripheral surface of the lower ring-shaped thrust plate 35D as indicated by the arrow, and then the lower portion in the inner sleeve 32 The radial direction communication passage 57 provided on the outer periphery of the inner sleeve 32 is directed to the outer peripheral side, and then flows upward through the long shaft direction communication passage 43. Further, a radial direction communication hole 56 provided in an upper portion of the inner sleeve 32 is provided. After going to the inner peripheral side, it flows downward through a bottomed recess 34f formed on the outer peripheral surface of the ring-shaped thrust plate 34D, and circulates so as to return to the pair of radial fluid dynamic pressure bearing portions 38, 39.

  In addition, as shown in FIG. 25G, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A <B), the pair of radial fluid dynamics The lubricating oil 33 passing through the pressure bearing portions 38 and 39 flows in the reverse direction with respect to FIG.

  Next, operations of the pair of thrust fluid dynamic pressure bearing portions 40 and 41 in the fluid dynamic pressure bearing 30J which is a main part of the tenth embodiment will be described with reference to FIG.

  As shown in FIGS. 26A to 26D, it is generated by a pair of thrust fluid dynamic pressure bearing portions 40 (e, f), 41 (g, h) formed on a pair of upper and lower ring thrust plates 34D, 35D. When a slight difference (dynamic pressure difference) occurs in the dynamic pressure values e to h, the lubricant 33 flows from the high pressure value toward the low direction according to the dynamic pressure difference, and therefore the deficiency of the lubricant 33 is reduced. In order to compensate, it is necessary to circulate the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in the tenth embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 26A, in each of the dynamic pressure values e to h described above, the generation of the dynamic pressure values is e> f, g = In the case of h, the lubricant 33 exiting here through the upper thrust fluid dynamic pressure bearing portion 40 is directed upward through the inner circumferential clearance 49 of the upper ring-shaped thrust plate 34D as indicated by an arrow. After that, the radial flow passage 45 formed in the ring-shaped thrust plate 34D flows toward the outer peripheral side, and further, the bottomed recess 34f formed on the outer peripheral surface of the ring-shaped thrust plate 34D moves downward. It circulates so as to flow back to the upper thrust fluid dynamic bearing portion 40. In this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 disposed below the upper thrust fluid dynamic pressure bearing portion 40, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  Further, as shown in FIG. 26B, when the generation of each dynamic pressure value is e <f, g = h, the lubricant that has left here through the upper thrust fluid dynamic pressure bearing portion 40. Since 33 circulates in a direction opposite to that shown in FIG. 26A, the fluid dynamic pressure bearings 38, 39, and 41 are not interposed here.

  In addition, as shown in FIG. 26C, when the generation of each dynamic pressure value is g> h and e = f, the lubrication that has exited through the lower thrust fluid dynamic pressure bearing portion 41 is provided. The agent 33 flows downward through the inner circumferential gap 50 of the lower ring-shaped thrust plate 35D as indicated by an arrow, and thereafter, the radial communication path 46 formed in the lower ring-shaped thrust plate 35D. To the outer peripheral side, and further flows upward through a bottomed recess 35f formed on the outer peripheral surface side of the lower ring-shaped thrust plate 35D so as to return to the lower thrust fluid dynamic pressure bearing portion 41. Circulate. In this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 disposed above the lower thrust fluid dynamic pressure bearing portion 41, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  In addition, as shown in FIG. 26D, when the generation of each dynamic pressure value is g <h and e = f, the lubrication that exits here through the lower thrust fluid dynamic pressure bearing portion 41. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 26C, the fluid dynamic pressure bearing portions 38, 39, and 40 are not interposed here.

  Accordingly, in the example of FIGS. 26A to 26D, the lubricant 33 that has exited here through one thrust fluid dynamic pressure bearing portion 40 (or 41) is transferred to the other thrust fluid dynamic pressure bearing portion 41 ( Alternatively, the lubricant 33 can be circulated without going through 40) and can be circulated without going through the pair of radial fluid dynamic pressure bearing portions 38, 39, so that the lubricant 33 can be returned in an appropriate amount.

FIGS. 27A to 27G are diagrams schematically illustrating the operation of a pair of radial fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are the main portions of the embodiment 11,
FIGS. 28A to 28D are diagrams schematically illustrating the operation of a pair of thrust fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are essential portions of the eleventh embodiment.

  In the fluid dynamic pressure bearing motor 10K (not shown) of the eleventh embodiment according to the present invention, as shown in FIG. 27A, the fluid dynamic pressure bearing 30K as the main part of the eleventh embodiment has been described above. Similar to the ninth and tenth embodiments, small diameter portions 12f and 12g smaller than the large diameter portion 12e are formed above and below the large diameter portion 12e of the shaft 12 fixed to the motor base 11 (FIG. 1), respectively. Unlike the ninth and tenth embodiments, the pair of ring-shaped thrust plates 34E and 35E described above with reference to FIG. 3 (E) are opposed to the upper and lower ends of the large-diameter portion 12e of the shaft 12, respectively. The outer peripheral surfaces of the pair of ring-shaped thrust plates 34E and 35E are fitted and fixed to the upper and lower inner peripheral surfaces of the inner sleeve 32, and are formed on the upper and lower portions of the shaft 12 as in the ninth and tenth embodiments. did Small-diameter portion 12f, 12 g on fitting the respective inner peripheral surfaces of the upper and lower pair of ring-shaped counterplate 37 engages with and is fixed.

  The fluid dynamic pressure bearing 30K, which is a main part of the above-described eleventh embodiment, is spaced along the shaft direction on either side between the outer peripheral surface of the large-diameter portion 12e of the shaft 12 and the inner peripheral surface of the inner sleeve 32. And each of the radial fluid dynamic pressure grooves of the pair of radial fluid dynamic pressure bearing portions 38 and 39 provided with predetermined lengths in the axial direction and upper and lower ends on the large diameter portion 12e side of the shaft 12. Each of the thrust fluid dynamic pressure grooves of the pair of thrust fluid dynamic pressure bearing portions 40, 41 provided on either one of the lower surface and the upper surface of the pair of ring-shaped thrust plates 34E, 35E, and the shaft 12 A long shaft direction communication passage (vertical communication passage) 51 provided along the shaft direction in the large diameter portion 12e, and an intermediate portion in the shaft direction within the large diameter portion 12e of the shaft 12, with one end side being a shaft Direction A radial direction communication path (lateral communication path) 52 that communicates with an intermediate portion of the path 51 and communicates between the pair of radial fluid dynamic pressure bearing portions 38 and 39 on the other end side, and a shaft direction within the large diameter portion 12e of the shaft 12 The one end communicates with the upper and lower parts of the shaft direction communication passage 51 and the other end side is provided with a pair of radial fluids via outer circumferential gaps 60 and 61 formed above and below the large-diameter portion 12e of the shaft 12. The dynamic pressure bearing portions 38 and 39 are configured by a pair of radial direction communication passages (lateral communication passages) 53 and 54 communicating with the upper and lower portions positioned above and below the pair of radial fluid dynamic pressure bearing portions 38 and 39. Yes.

  In the eleventh embodiment, a pair of upper and lower ring-shaped counter plates 36 and 37 are fixed to the small-diameter portions 12f and 12g formed on the upper and lower sides of the shaft 12 that is fixedly installed. Thrust fluid dynamic pressure grooves are formed on the upper and lower surfaces (both sides) of the plates 34E and 35E by herringbone or a ray-lay step.

  Here, operation | movement of a pair of radial fluid dynamic pressure bearing parts 38 and 39 among the fluid dynamic pressure bearings 30K used as the principal part of Example 11 is demonstrated using FIG.

  As shown in FIG. 27A, in the eleventh embodiment, as in the ninth and tenth embodiments, a slight difference (dynamic pressure difference) between the dynamic pressure values a to d generated by the pair of radial fluid dynamic pressure bearing portions 38 and 39 is obtained. ) Occurs, the lubricant 33 flows in the direction from the high dynamic pressure value to the low direction according to the dynamic pressure difference. Therefore, the lubricant 33 is circulated to compensate for the insufficient amount of the lubricant 33, and an appropriate amount is obtained. It is necessary to return the lubricant 33.

  Therefore, in Example 11, when the inner sleeve 32 side rotates, as shown in FIG. 27B, in each of the above-described dynamic pressure values a to d, the generation of the dynamic pressure values is a> b, c = In the case of d, the lubricant 33 exiting through the upper radial fluid dynamic pressure bearing portion 38 enters the radial communication passage 52 provided at the intermediate portion in the shaft 12 as indicated by an arrow. It goes to the circumferential side, and then flows upward in the long shaft direction communication passage 51 provided in the shaft 12, and further, the radial direction communication passage 53 provided in the upper portion in the shaft 12 toward the outer periphery side. After that, it circulates so as to return to the upper radial fluid dynamic bearing portion 38 through an outer peripheral gap 60 formed on the upper outer periphery of the shaft 12. In this case, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and a pair of upper and lower ring-shaped thrust plates 34E, The pair of thrust fluid dynamic pressure bearing portions 40 and 41 formed in 35E is not interposed.

  In addition, as shown in FIG. 27C, when the generation of each dynamic pressure value is a <b and c = d, the lubricant that has left here through the upper radial fluid dynamic bearing portion 38. Since 33 circulates in the opposite direction with respect to FIG. 27 (B) described above, the other fluid dynamic pressure bearing portions 39, 40, 41 are not interposed here either.

  In addition, as shown in FIG. 27D, when the generation of each dynamic pressure value is c> d and a = b, the lubrication that exits here through the lower radial fluid dynamic bearing portion 39. The agent 33 passes through the outer circumferential clearance 61 formed in the lower outer periphery of the shaft 12 as indicated by the arrow, and then goes to the radial direction communication path 54 provided in the lower portion of the shaft 12 toward the inner peripheral side. The lower radial fluid dynamic pressure bearing flows through the long shaft direction communication passage 51 provided in the upper portion and further flows in the radial direction communication passage 52 provided in the intermediate portion of the shaft 12 toward the outer peripheral side. Circulate to return to section 39. In this case, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and a pair of upper and lower ring thrust plates 34E. , 35E is not interposed with a pair of thrust fluid dynamic pressure bearing portions 40, 41.

  In addition, as shown in FIG. 27E, when the generation of each dynamic pressure value is c <d and a = b, the lubrication that has exited through the lower radial fluid dynamic bearing portion 39 is provided. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 27D described above, the other fluid dynamic pressure bearing portions 38, 40, 41 are not interposed here either.

  Accordingly, in the example of FIGS. 27B to 27E, the lubricant 33 that has exited here through one radial fluid dynamic pressure bearing portion 38 (or 39) is transferred to the other radial fluid dynamic pressure bearing portion 39 ( Or 38) and can be circulated without the pair of thrust fluid dynamic pressure bearing portions 40, 41 formed on the pair of upper and lower ring-shaped thrust plates 34E, 35E. Can be returned.

  Further, FIGS. 27 (F) and 27 (G) show the circulation path of the lubricant 33 by the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39. FIG.

  As shown in FIG. 27 (F), when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A> B), the pair of radial fluid dynamic pressure bearings The lubricating oil 33 passing through the portions 38 and 39 passes through the outer circumferential clearance 61 formed in the lower outer periphery of the shaft 12 as indicated by the arrow, and passes through the radial communication path 54 provided in the lower portion of the shaft 12 toward the inner peripheral side. After this, the long shaft direction communication passage 51 provided in the shaft 12 flows upward, and further, the radial direction communication passage 53 provided in the upper portion of the shaft 12 is directed to the outer peripheral side, and then the shaft 12. It circulates so that it may return to a pair of radial fluid dynamic pressure bearing parts 38 and 39 via the peripheral clearance 60 formed in the upper perimeter of the above.

  In addition, as shown in FIG. 27G, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A <B), the pair of radial fluid dynamics The lubricating oil 33 passing through the pressure bearing portions 38 and 39 flows in the reverse direction with respect to FIG.

  Next, operations of the pair of thrust fluid dynamic pressure bearing portions 40 and 41 in the fluid dynamic pressure bearing 30K as the main part of the eleventh embodiment will be described with reference to FIG.

  As shown in FIGS. 28 (A) to (D), it is generated by a pair of thrust fluid dynamic pressure bearing portions 40 (e, f), 41 (g, h) formed on a pair of upper and lower ring thrust plates 34E, 35E. When a slight difference (dynamic pressure difference) occurs in the dynamic pressure values e to h, the lubricant 33 flows from the high pressure value toward the low direction according to the dynamic pressure difference, and therefore the deficiency of the lubricant 33 is reduced. In order to compensate, it is necessary to circulate the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in Example 11, when the inner sleeve 32 side rotates, as shown in FIG. 28A, in each of the dynamic pressure values e to h described above, the generation of the dynamic pressure values is e> f, g = In the case of h, the lubricant 33 exiting through the upper thrust fluid dynamic pressure bearing 40 is directed downward in the shaft direction communication path 51 provided in the shaft 12 as indicated by an arrow. After this, the radial direction communication passage 53 provided in the upper part in the shaft 12 flows toward the outer peripheral side, and further flows upward in the outer peripheral clearance 60 formed in the upper outer periphery of the shaft 12 to raise the upper thrust. It circulates back to the fluid dynamic bearing 40. In this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 disposed below the upper thrust fluid dynamic pressure bearing portion 40, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  In addition, as shown in FIG. 28B, when the generation of each dynamic pressure value is e <f, g = h, the lubricant that has left here through the upper thrust fluid dynamic pressure bearing portion 40. Since 33 circulates in a direction opposite to that shown in FIG. 28A, the fluid dynamic pressure bearing portions 38, 39, and 41 are not interposed here.

  In addition, as shown in FIG. 28C, when the generation of each dynamic pressure value is g> h and e = f, the lubrication that exits through the lower thrust fluid dynamic pressure bearing portion 41 is provided. The agent 33 flows upward in the shaft direction communication path 51 provided in the shaft 12 as indicated by an arrow, and thereafter, the radial direction communication path 54 provided in a lower portion in the shaft 12 is directed toward the outer peripheral side. Furthermore, it circulates so as to flow downward in the outer peripheral clearance 61 formed on the upper outer periphery of the shaft 12 and return to the lower thrust fluid dynamic pressure bearing portion 41. In this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 disposed above the lower thrust fluid dynamic pressure bearing portion 41, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  In addition, as shown in FIG. 28D, when the generation of each dynamic pressure value is g <h and e = f, the lubrication that exits here through the lower thrust fluid dynamic pressure bearing portion 41. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 28C, the fluid dynamic pressure bearing portions 38, 39, and 40 are not interposed here.

  Accordingly, in the example of FIGS. 28A to 28D, the lubricant 33 that has exited here through one thrust fluid dynamic pressure bearing portion 40 (or 41) is transferred to the other thrust fluid dynamic pressure bearing portion 41 ( Alternatively, the lubricant 33 can be circulated without going through 40) and can be circulated without going through the pair of radial fluid dynamic pressure bearing portions 38, 39, so that the lubricant 33 can be returned in an appropriate amount.

29 (A) to 29 (G) are diagrams schematically illustrating the operation of a pair of radial fluid dynamic pressure bearing portions among the fluid dynamic pressure bearings that are essential portions of the twelfth embodiment,
FIGS. 30A to 30D are diagrams schematically illustrating the operation of a pair of thrust fluid dynamic pressure bearings among the fluid dynamic pressure bearings that are essential parts of the twelfth embodiment.

  In the fluid dynamic bearing motor 10L (not shown) according to the twelfth embodiment of the present invention, as shown in FIG. 29 (A), the fluid dynamic bearing 30L, which is the main part of the twelfth embodiment, is described above. Similarly to the eleventh embodiment, the pair of ring-shaped thrust plates 34E and 35E described above with reference to FIG. 3 (E) are opposed to the upper and lower ends of the large diameter portion 12e of the shaft 12, respectively. The outer peripheral surfaces of the ring-shaped thrust plates 34E and 35E are fitted and fixed to the upper and lower inner peripheral surfaces of the inner sleeve 32, and a pair of upper and lower small diameter portions 12f and 12g formed on the upper and lower sides of the shaft 12 are fixed. The inner peripheral surfaces of the ring-shaped counter plates 36 and 37 are fitted and fixed.

  The fluid dynamic pressure bearing 30L, which is a main part of the above-described embodiment 12, is spaced along the shaft direction on either side between the outer peripheral surface of the large-diameter portion 12e of the shaft 12 and the inner peripheral surface of the inner sleeve 32. And each of the radial fluid dynamic pressure grooves of the pair of radial fluid dynamic pressure bearing portions 38 and 39 provided with predetermined lengths in the axial direction and upper and lower ends on the large diameter portion 12e side of the shaft 12. Each of the thrust fluid dynamic pressure grooves of the pair of thrust fluid dynamic pressure bearing portions 40, 41 provided on either one of the lower surface and the upper surface of the ring-shaped thrust plates 34E, 35E, and the outer sleeve 31 A long shaft direction communication path (longitudinal communication path) 43 provided along the shaft direction on either side between the inner sleeve 32 and the inner sleeve 32 and an intermediate portion of the inner sleeve 32 in the shaft direction. A radial communication passage (lateral communication passage) 44 having one end communicating with a pair of radial fluid dynamic pressure bearing portions 38 and 39 and the other end communicating with an intermediate portion of the shaft communication passage 43, and the inner sleeve 32. The pair of radial fluid dynamic pressures on the pair of radial fluid dynamic pressure bearing portions 38, 39 via outer peripheral gaps 60, 61 provided at the upper and lower parts in the shaft direction and having one end formed on the upper and lower outer periphery of the shaft 12, respectively. A pair of radial communication paths (lateral communication paths) 56, 57 that communicate with the upper and lower parts positioned above and below the bearing portions 38, 39 and that each other end communicates with the upper and lower parts of the shaft direction communication path 43, and the shaft 12 A pair of shaft direction communication passages 62, 63 provided in a short length along the shaft direction from the upper and lower ends of the shaft, and a radial direction provided in the upper and lower ends of the shaft 12 A pair of radial communication paths (lateral communication paths) each having one end side communicating with a pair of short shaft direction communication paths 62, 63 and each other end communicating with outer circumferential gaps 60, 61 formed on the upper and lower outer circumferences of the shaft 12. 53 and 54.

  In the twelfth embodiment, a pair of upper and lower ring-shaped counter plates 36 and 37 are fixed to the small-diameter portions 12f and 12g formed on the upper and lower sides of the shaft 12 that is fixedly installed. Each thrust fluid dynamic pressure is formed on the upper and lower surfaces (both surfaces) of the plates 34E and 35E by a herringbone or a Rayleigh step.

  Here, operation | movement of a pair of radial fluid dynamic pressure bearing parts 38 and 39 among the fluid dynamic pressure bearings 30L used as the principal part of Example 12 is demonstrated using FIG.

  As shown in FIG. 29A, in the twelfth embodiment as well as in the ninth to eleventh embodiments, a slight difference (dynamic pressure difference) between the dynamic pressure values a to d generated by the pair of radial fluid dynamic pressure bearing portions 38 and 39 is obtained. ) Occurs, the lubricant 33 flows in the direction from the high dynamic pressure value to the low direction according to the dynamic pressure difference. Therefore, the lubricant 33 is circulated to compensate for the insufficient amount of the lubricant 33, and an appropriate amount is obtained. It is necessary to return the lubricant 33.

  Therefore, in the twelfth embodiment, when the inner sleeve 32 side is rotated, as shown in FIG. 29B, in each of the dynamic pressure values a to d described above, the generation of the dynamic pressure values is a> b, c = In the case of d, the lubricant 33 that has exited through the upper radial fluid dynamic pressure bearing portion 38 passes through the radial communication path 44 provided at the intermediate portion in the inner sleeve 32 as indicated by an arrow. It goes to the outer peripheral side, and then flows upward in a long shaft direction communication path 43 provided between the outer sleeve 31 and the inner sleeve 32, and is further provided in a radial direction provided at an upper portion in the inner sleeve 32. After passing through the communication path 56 toward the inner peripheral side, it circulates so as to return to the upper radial fluid dynamic pressure bearing portion 38 through an outer peripheral clearance 60 formed in the upper outer periphery of the shaft 12. In this case, the lubricant 33 circulates without passing through the lower radial fluid dynamic pressure bearing portion 39 disposed below the upper radial fluid dynamic pressure bearing portion 38, and a pair of upper and lower ring-shaped thrust plates 34E, The pair of thrust fluid dynamic pressure bearing portions 40 and 41 formed in 35E is not interposed.

  In addition, as shown in FIG. 29C, when the generation of each dynamic pressure value is a <b and c = d, the lubricant that has exited here through the upper radial fluid dynamic bearing portion 38. Since 33 circulates in the opposite direction with respect to FIG. 29B described above, the other fluid dynamic pressure bearing portions 39, 40, 41 are not interposed here.

  Also, as shown in FIG. 29D, when the generation of each dynamic pressure value is c> d and a = b, the lubrication exiting through the lower radial fluid dynamic bearing portion 39 is provided. As indicated by the arrow, the agent 33 passes through the outer peripheral clearance 61 formed in the lower outer periphery of the shaft 12 and goes to the radial direction communication path 57 provided in the lower portion in the inner sleeve 32 toward the outer peripheral side. The shaft direction communication passage 43 flows upward, and further flows in the radial direction communication passage 44 provided at an intermediate portion in the inner sleeve 32 toward the inner peripheral side, and returns to the lower radial fluid dynamic pressure bearing portion 39. Circulate like so. In this case, the lubricant 33 circulates without passing through the upper radial fluid dynamic pressure bearing portion 38 disposed above the lower radial fluid dynamic pressure bearing portion 39, and a pair of upper and lower ring thrust plates 34E. , 35E is not interposed with a pair of thrust fluid dynamic pressure bearing portions 40, 41.

  Further, as shown in FIG. 29E, when the generation of each dynamic pressure value is c <d and a = b, the lubrication that exits here through the lower radial fluid dynamic bearing portion 39. Since the agent 33 flows and circulates in the opposite direction with respect to FIG. 29D described above, the other fluid dynamic pressure bearing portions 38, 40, and 41 are not interposed here either.

  Accordingly, in the example of FIGS. 29B to 29E, the lubricant 33 that has exited through the one radial fluid dynamic pressure bearing portion 38 (or 39) passes through the other radial fluid dynamic pressure bearing portion 39 ( Or 38) and can be circulated without the pair of thrust fluid dynamic pressure bearing portions 40, 41 formed on the pair of upper and lower ring-shaped thrust plates 34E, 35E. Can be returned.

  Further, FIGS. 29 (F) and 29 (G) show the circulation path of the lubricant 33 by the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39. FIG.

  As shown in FIG. 29 (F), when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A> B), the pair of radial fluid dynamic pressure bearings The lubricating oil 33 passing through the portions 38 and 39 is directed to the outer peripheral side through a radial communication passage 57 provided at a lower portion in the inner sleeve 32 through an outer peripheral gap 61 formed in the lower outer periphery of the shaft 12 as indicated by an arrow. After that, it flows upward in the long shaft direction communication passage 43, and further, the radial direction communication hole 56 provided in the upper part in the inner sleeve 32 is directed to the inner peripheral side, and then on the upper outer periphery of the shaft 12. It circulates so as to return to the pair of radial fluid dynamic pressure bearing portions 38 and 39 through the formed outer circumferential gap 60.

  Further, as shown in FIG. 29G, when the dynamic pressure values A and B generated in the pair of radial fluid dynamic pressure bearing portions 38 and 39 are unbalanced (A <B), the pair of radial fluid dynamics The lubricating oil 33 passing through the pressure bearing portions 38 and 39 flows in the opposite direction to the above FIG. 29 (F) and circulates.

  Next, the operation of the pair of thrust fluid dynamic pressure bearing portions 40 and 41 in the fluid dynamic pressure bearing 30L, which is a main part of the twelfth embodiment, will be described with reference to FIG.

  As shown in FIGS. 30A to 30D, it is generated by a pair of thrust fluid dynamic pressure bearing portions 40 (e, f), 41 (g, h) formed on a pair of upper and lower ring thrust plates 34E, 35E. When a slight difference (dynamic pressure difference) occurs in the dynamic pressure values e to h, the lubricant 33 flows from the high pressure value toward the low direction according to the dynamic pressure difference, and therefore the deficiency of the lubricant 33 is reduced. In order to compensate, it is necessary to circulate the lubricant 33 and return an appropriate amount of the lubricant 33.

  Therefore, in the twelfth embodiment, when the inner sleeve 32 side rotates, as shown in FIG. 30A, in each of the dynamic pressure values e to h described above, the generation of the dynamic pressure values is e> f, g = In the case of h, the lubricant 33 exiting through the upper thrust fluid dynamic pressure bearing portion 40 is a short shaft direction communication passage 62 provided at an upper portion in the shaft 12 as indicated by an arrow. After that, the radial direction communication path 53 provided in the upper part in the shaft 12 flows toward the outer peripheral side, and further, the outer peripheral clearance 60 formed on the upper outer periphery of the shaft 12 moves upward. It circulates so as to flow back to the upper thrust fluid dynamic bearing portion 40. In this case, the lubricant 33 circulates without passing through the lower thrust fluid dynamic pressure bearing portion 41 disposed below the upper thrust fluid dynamic pressure bearing portion 40, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  Further, as shown in FIG. 30B, when the generation of each dynamic pressure value is e <f, g = h, the lubricant that has left here through the upper thrust fluid dynamic pressure bearing portion 40 Since 33 circulates in the opposite direction with respect to FIG. 30A described above, the other fluid dynamic pressure bearing portions 38, 39, 41 are not interposed here.

  Further, as shown in FIG. 30C, when the generation of each dynamic pressure value is g> h and e = f, the lubrication that exits through the lower thrust fluid dynamic pressure bearing 41 is provided. The agent 33 flows upward in the short shaft direction communication path 63 provided in the lower part in the shaft 12 as indicated by the arrow, and thereafter, the radial direction communication path 54 provided in the lower part in the shaft 12. Is further circulated so as to flow downward and return to the lower thrust fluid dynamic pressure bearing portion 41 through the outer peripheral clearance 61 formed on the lower outer periphery of the shaft 12. In this case, the lubricant 33 circulates without passing through the upper thrust fluid dynamic pressure bearing portion 40 disposed above the lower thrust fluid dynamic pressure bearing portion 41, and a pair of radial fluid dynamic pressure bearing portions. 38 and 39 are not used.

  Further, as shown in FIG. 30D, when the generation of each dynamic pressure value is g <h and e = f, the lubrication that exits here through the lower thrust fluid dynamic pressure bearing portion 41. Since the agent 33 flows and circulates in the reverse direction with respect to FIG. 30C, the fluid dynamic pressure bearing portions 38, 39, and 40 are not interposed here.

  Accordingly, in the example of FIGS. 30A to 30D, the lubricant 33 that has exited here through one thrust fluid dynamic pressure bearing portion 40 (or 41) is transferred to the other thrust fluid dynamic pressure bearing portion 41 ( Alternatively, the lubricant 33 can be circulated without going through 40) and can be circulated without going through the pair of radial fluid dynamic pressure bearing portions 38, 39, so that the lubricant 33 can be returned in an appropriate amount.

  As described above in detail, according to the fluid dynamic bearing motor according to the present invention to which any one of the fluid dynamic pressure bearings 30A to 30 of the first to twelfth embodiments is applied, the pair of fluid dynamic bearings according to the present invention is particularly suitable. Each radial fluid dynamic pressure bearing portion of the radial fluid dynamic pressure bearing portion and each thrust fluid dynamic pressure bearing portion of the pair of thrust fluid dynamic pressure bearing portions are connected via a fluid dynamic pressure bearing portion other than each fluid dynamic pressure bearing portion itself. Since each communication passage means functions to cancel the imbalance of the dynamic pressure pump balance, each communication passage means functions to cancel the imbalance of the dynamic pressure pump balance. The flow of oil due to the difference in the dynamic pressure of the oil does not affect the upper or lower thrust fluid dynamic pressure bearing portion, and the lubricant can be returned in an appropriate amount. Performance improvement and reliability It is possible to sex improvement.

BRIEF DESCRIPTION OF THE DRAWINGS (A) is the longitudinal cross-sectional view which showed the fluid dynamic pressure bearing motor of Example 1 which concerns on this invention, (B) is (a) enlarged view. In the fluid dynamic pressure bearing motor of Example 1 which concerns on this invention, it is the longitudinal cross-sectional view which expanded and showed the fluid dynamic pressure bearing used as the principal part of Example 1. FIG. (A)-(E) is the perspective view which expanded and showed the example which each changed the shape of the ring-shaped thrust plate among the fluid dynamic pressure bearings shown in FIG. (A)-(C) is sectional drawing which showed the example which each changed the shape of the shaft direction communicating path among the fluid dynamic pressure bearings shown in FIG. 2 along the roll line of FIG. (A)-(G) is the figure typically shown in order to demonstrate operation | movement of a pair of radial fluid dynamic pressure bearing parts among the fluid dynamic pressure bearings used as the principal part of Example 1. FIG. (A)-(F) is the figure typically shown in order to demonstrate operation | movement of a pair of thrust fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 1. FIG. In the fluid dynamic pressure bearing motor of Example 2 which concerns on this invention, it is the longitudinal cross-sectional view which expanded and showed the fluid dynamic pressure bearing used as the principal part of Example 2. FIG. (A)-(G) is the figure typically shown in order to demonstrate operation | movement of a pair of radial fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 2. FIG. (A)-(F) is the figure typically shown in order to demonstrate operation | movement of a pair of thrust fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 2. FIG. In the fluid dynamic pressure bearing motor of Example 3 which concerns on this invention, it is the longitudinal cross-sectional view which expanded and showed the fluid dynamic pressure bearing used as the principal part of Example 3. FIG. (A)-(G) is the figure typically shown in order to demonstrate operation | movement of a pair of radial fluid dynamic pressure bearing parts among the fluid dynamic pressure bearings used as the principal part of Example 3. FIG. (A)-(F) is the figure typically shown in order to demonstrate operation | movement of a pair of thrust fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 3. FIG. (A)-(G) is the figure typically shown in order to demonstrate operation | movement of a pair of radial fluid dynamic pressure bearing parts among the fluid dynamic pressure bearings used as the principal part of Example 4. FIG. (A)-(F) is the figure typically shown in order to demonstrate operation | movement of a pair of thrust fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 4. FIG. (A)-(G) is the figure typically shown in order to demonstrate operation | movement of a pair of radial fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 5. FIG. (A)-(F) is the figure typically shown in order to demonstrate operation | movement of a pair of thrust fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 5. FIG. (A)-(G) is the figure typically shown in order to demonstrate operation | movement of a radial fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 6. FIG. (A)-(D) are the figures typically shown in order to demonstrate operation | movement of a thrust fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 6. FIG. (A)-(G) is the figure typically shown in order to demonstrate operation | movement of a pair of radial fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 7. FIG. (A)-(D) are the figures typically shown in order to demonstrate operation | movement of a pair of thrust fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 7. FIG. (A)-(G) are the figures typically shown in order to demonstrate operation | movement of a pair of radial fluid dynamic pressure bearing parts among the fluid dynamic pressure bearings used as the principal part of Example 8. FIG. (A)-(D) is the figure typically shown in order to demonstrate operation | movement of a pair of thrust fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 8. FIG. (A)-(G) is the figure typically shown in order to demonstrate operation | movement of a pair of radial fluid dynamic pressure bearing parts among the fluid dynamic pressure bearings used as the principal part of Example 9. FIG. (A)-(D) are the figures typically shown in order to demonstrate operation | movement of a pair of thrust fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 9. FIG. (A)-(G) are the figures typically shown in order to demonstrate operation | movement of a pair of radial fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 10. FIG. (A)-(D) is the figure typically shown in order to demonstrate operation | movement of a pair of thrust fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 10. FIG. (A)-(G) is the figure typically shown in order to demonstrate operation | movement of a pair of radial fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 11. FIG. (A)-(D) are the figures typically shown in order to demonstrate operation | movement of a pair of thrust fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 11. FIG. (A)-(G) are the figures typically shown in order to demonstrate operation | movement of a pair of radial fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 12. FIG. (A)-(D) are the figures typically shown in order to demonstrate operation | movement of a pair of thrust fluid dynamic pressure bearing part among the fluid dynamic pressure bearings used as the principal part of Example 12. FIG. It is the longitudinal cross-sectional view which showed an example of the conventional fluid dynamic pressure bearing. It is the longitudinal cross-sectional view which showed the other example of the conventional fluid dynamic pressure bearing.

Explanation of symbols

10A (-10L) ... Fluid dynamic pressure bearing motor of Examples 1-12,
DESCRIPTION OF SYMBOLS 11 ... Motor base, 12 ... Shaft, 13 ... Stator core, 14 ... Coil,
15 ... Flexible printed circuit board, 16 ... Connector,
17 ... Hub, 18 ... Spacer, 19 ... Rotor yoke, 20 ... Magnet,
30A-30L ... Fluid dynamic pressure bearings of Examples 1-12,
31 ... Outer sleeve, 32 ... Inner sleeve,
33 ... lubricant,
34 (34A to 34E) ... upper ring-shaped thrust plate,
35 (35A to 35E) ... lower ring-shaped thrust plate,
36 ... Ring-shaped counter plate on the upper side,
37 ... The upper ring-shaped counter plate,
38, 39 ... A pair of radial fluid dynamic pressure bearing portions in Examples 1 to 12,
40, 41 ... A pair of thrust fluid dynamic pressure bearing portions in Examples 1 to 4 and 9 to 12,
40 ', 41' ... A pair of thrust fluid dynamic pressure bearing parts in Examples 5 to 8,
42, 43 ... Shaft direction communication path (vertical communication path),
44. Radial direction communication passage (horizontal communication passage),
45, 46: a pair of radial communication paths (lateral communication paths) formed in the pair of ring-shaped thrust plates,
47, 48 ... outer circumferential clearances of a pair of ring-shaped thrust plates,
49, 50 ... Inner circumferential clearances of a pair of ring-shaped thrust plates,
51. Shaft direction communication path (vertical communication path) provided in the shaft,
52-54 ... Radial direction communication path (lateral communication path) provided in the shaft,
55 ... Occlusion plug,
56, 57 ... A pair of radial communication paths (lateral communication paths) provided in the inner sleeve,
58, 59 ... outer peripheral gap formed in the outer peripheral upper and lower parts of the inner sleeve,
60, 61 ... outer peripheral clearance formed in the upper and lower outer periphery of the large diameter portion of the shaft,
62, 63 ... a short shaft direction communication passage formed in the upper and lower ends of the large diameter portion of the shaft,
HD ... Hard disk,
R ... rotor, S ... stator.

Claims (3)

A shaft pivotally attached to the central hole of the sleeve formed in an annular shape;
Electromagnetic driving means for rotating the rotor side relative to the stator side when either the shaft side or the sleeve side is configured as a stator side and the other side is configured as a rotor side;
A pair of radial fluid dynamic pressure bearing portions that are provided at intervals in the shaft direction corresponding to the longitudinal direction of the shaft and that support a radial load on the rotor side via a lubricant;
A pair of thrust fluid dynamic pressure bearings provided on one end side in the shaft direction or on each end side in the shaft direction and supporting a thrust load on the rotor side via the lubricant In a fluid dynamic pressure bearing motor comprising:
The radial fluid dynamic pressure bearing portions of the pair of radial fluid dynamic pressure bearing portions and the thrust fluid dynamic pressure bearing portions of the pair of thrust fluid dynamic pressure bearing portions are fluid dynamic pressures other than the fluid dynamic pressure bearing portions themselves. A fluid dynamic bearing motor characterized in that a communication passage means for circulating the lubricant without passing through a bearing portion is provided. The fluid dynamic bearing motor according to claim 1,
Each radial fluid dynamic pressure groove of the pair of radial fluid dynamic pressure bearing portions is provided on either the inner peripheral surface of the central hole of the sleeve or the outer peripheral surface of the shaft, and the pair of thrust fluid dynamic pressure bearing portions Each thrust fluid dynamic pressure groove is opposed to the end portion in the shaft direction of the sleeve or the end portion in the shaft direction of the ring-shaped thrust plate opposed to the end portion in the shaft direction of the sleeve or the large diameter portion formed in the shaft. A fluid dynamic pressure bearing motor provided on any one of ring-shaped thrust plates. In the fluid dynamic bearing motor according to claim 1 or 2,
The communication passage means is provided in a radial direction at an intermediate portion in the shaft direction, and one end side communicates between the pair of radial fluid dynamic pressure bearing portions. And a first radial direction communication path whose other end side communicates with an intermediate portion of the shaft direction communication path, and one end side is provided on the pair of radial fluid dynamic pressure bearing parts side in the radial direction above and below the shaft direction. And communicated with the upper and lower parts positioned above and below the pair of radial fluid dynamic pressure bearing parts, and each end side communicated with the upper and lower parts of the shaft direction communication path, and between each one end side and each other side A fluid dynamic pressure bearing motor having at least second and third radial direction communication passages communicating with the thrust fluid dynamic pressure bearing portions.

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