JP2005282770A - Hydrodynamic bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve adhesive force between a resin housing and a metal bracket. <P>SOLUTION: A bearing sleeve 8 is fixed inside the housing 7 for supporting a shaft member 2 in no contact therewith in the radial direction using the hydrodynamic operation of lubricating oil generated in a radial bearing gap between the shaft member 2 and the bearing sleeve 8. Onto the outer periphery of the housing 7, the metal bracket 6 is adhered and fixed via which a stator 4 of a motor is mounted thereon. The housing 7 is formed of a resin, and alkaline etching treatment is given to the surface thereof to improve adhesive force between the resin housing 7 and the metal bracket 6. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydrodynamic bearing device. The hydrodynamic bearing device here is an information device, for example, a magnetic disk device such as HDD or FDD, an optical disk device such as CD-ROM, CD-R / RW, or DVD-ROM / RAM, or a magneto-optical disk such as MD or MO. It is suitable as a bearing device for a spindle motor such as a device, a polygon scanner motor of a laser beam printer (LBP), a color wheel of a projector, or a small motor such as an electric device such as an axial fan.

  In addition to high rotational accuracy, the various motors are required to have high speed, low cost, low noise, and the like. One of the components that determine the required performance is a bearing that supports the spindle of the motor, and in recent years, as this type of bearing, the use of a hydrodynamic bearing having characteristics excellent in the required performance has been studied. Or it is actually used.

  As an example, a hydrodynamic bearing device used in a spindle motor of a disk drive device such as an HDD is described in Japanese Patent Application Laid-Open No. 2000-291648. In this bearing device, a bearing sleeve is fixed to the inner periphery of a bottomed cylindrical housing, and a shaft member having a flange portion projecting to the outer diameter side is inserted into the inner periphery of the bearing sleeve to be fixed to the rotating shaft member. A fluid dynamic pressure is generated in a radial bearing gap or a thrust bearing gap formed between the side members (bearing sleeve, housing, etc.), and the shaft member is supported in a non-contact manner by this fluid dynamic pressure.

By the way, this type of spindle motor rotates a shaft member with an exciting force generated between a motor rotor made of a magnet and a motor stator made of a coil, and conventionally, a member (disk) that rotates the motor rotor together with the shaft member. In many cases, the motor stator is fixed to a metal holding member, for example, a motor bracket, which is fixed to the outer periphery of the housing of the hydrodynamic bearing device.
JP 2000-291648 A

  The motor bracket and the housing are generally fixed by adhesion. Conventionally, since both the motor bracket and the housing are made of metal and the bonding portion is metal bonding, a necessary and sufficient bonding force has been obtained.

  In recent years, however, the use of resin for the housing has been studied. In this case, a sufficient adhesive force cannot be obtained between the resin housing and the metal motor bracket, and how to obtain a strong adhesive force between the two becomes a problem. As a countermeasure, while anaerobic adhesive was used, it was also attempted to apply a primer containing metal ions to the resin surface, but the adhesive strength was obtained only about 1/10 to 1/5 of the case of metals, Sufficient adhesive strength was not obtained.

  In view of such a situation, an object of the present invention is to improve the adhesive force between both members when one of a housing and a holding member is a resin molded product.

  As means for achieving this object, in the present invention, a housing, a bearing sleeve fixed inside the housing, a rotating member that rotates relative to the housing and the bearing sleeve, and a radial bearing between the bearing sleeve and the rotating member are provided. In a hydrodynamic bearing device comprising: a radial bearing portion that supports the rotating member in a non-contact manner in the radial direction by a dynamic pressure action of fluid generated in a gap; and a holding member that holds the housing by adhesion to the housing. At least one of them is a resin molded product, and at least an adhesion portion of the resin molded product is subjected to a surface treatment for strengthening the adhesive force with the mating member. As the holding member, for example, a bracket (motor bracket) having a motor stator attachment portion is conceivable. As the surface treatment method, a physical or chemical surface treatment method other than a surface treatment method by mechanical means (for example, sandpaper blasting or blasting (sandblasting, etc.)) can be adopted. For example, an alkali etching process, a UV process, a plasma etching process, or a metal plating process can be used.

  By performing such a surface treatment, even when either or both of the housing and the holding member are resin molded products, a sufficient adhesive force can be obtained between the two members, so that the impact load is high. The coupling strength can be ensured, and the durability and reliability of the bearing device can be improved.

  One of the housing and the holding member can be a resin molded product, the other can be a metal molded product, and the other can be a resin molded product. When either one is a resin molded product and the other is made of metal, the surface treatment may be applied to the resin molded product. When both are resin molded products, the surface treatment is desirably performed on both resin molded products, but may be performed on only one of the resin molded products as long as sufficient adhesive force is obtained.

  The resin forming the resin molded product is not particularly limited as long as it is a thermoplastic resin. For example, examples of the amorphous resin include polysulfone (PSF), polyethersulfone (PES), polyphenylsulfone (PPSF), and polyether. As a crystalline resin such as imide (PEI), liquid crystal polymer (LCP), polyether ether ketone (PEEK), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), or the like can be used.

  In addition, a filler can be added to the resin as necessary. The type of filler is not particularly limited, for example, fibrous filler such as glass fiber, whisker filler such as potassium titanate, scaly filler such as mica, carbon fiber, carbon black, graphite, carbon nanomaterial, Fibrous or powdery conductive fillers such as metal powder can be used. These fillers may be used alone or in combination of two or more.

  As the surface treatment, it is desirable to remove the skin layer on the surface of the resin molded product. The skin layer is a smooth thin layer with little filler, and is formed on the contact surface with the mold along with injection molding. By removing this skin layer, a layer (core layer) rich in fillers consisting of fibers, etc., appears on the surface, so that the anchor effect at the interface and the wettability of the adhesive increase, and the adhesive strength Will increase. As a specific example of the process for removing the skin layer as described above, for example, an alkali etching process can be given.

  Further, as the surface treatment, one that activates (ionizes) the surface of the resin molded product can be used. By activating the surface, the affinity (compatibility) with the adhesive is improved, so that the adhesive strength can be similarly improved. Examples of this type of surface treatment include UV treatment that activates the resin surface by the action of ultraviolet rays and ozone, or plasma etching treatment that activates the resin surface by generating plasma under vacuum (or normal pressure). Can do.

  In addition, as a surface treatment, a metal plating layer can be formed on the surface of the resin molded product. Thereby, since an adhesion part turns into metal adhesion, adhesive strength can be raised.

  By the way, the motor of the information equipment is used regardless of whether it is in a high temperature environment or a low temperature environment, and high thermal shock resistance is required. The inventors have verified that the thermal shock resistance of the adhesive strength depends on the adhesive clearance between the outer periphery of the housing and the inner periphery of the holding member, and if the width (radius amount) of this adhesive clearance exceeds 30 μm, It was found that the thermal shock resistance of the strength was greatly reduced. Therefore, it is desirable to set the adhesion clearance between the housing and the holding member to 30 μm or less.

  Since the motor having each of the dynamic pressure bearing devices described above, the motor stator attached to the bracket, and the motor rotor attached to the rotating member ensures a high adhesive force between the housing and the bracket, Excellent properties in terms of durability and reliability.

  According to the present invention, a high adhesive force can be ensured between the housing and the holding member, and durability and reliability can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 conceptually shows a configuration example of a spindle motor for information equipment incorporating a fluid dynamic bearing device 1 according to this embodiment. This spindle motor is used in a disk drive device such as an HDD, and includes a hydrodynamic bearing device 1 that rotatably supports a shaft member 2 in a non-contact manner, a disk hub 3 mounted on the shaft member 2, and a radial direction, for example. The motor stator 4 and the motor rotor 5 are provided to face each other through the gap. The motor stator 4 is made of a coil, for example, and is attached to the outer periphery of the bracket 6. The motor rotor 5 is made of, for example, a magnet and is attached to the inner periphery of the disk hub 3. As will be described later, the housing 7 of the hydrodynamic bearing device 1 is bonded and fixed to the inner periphery of the bracket 6. The disk hub 3 holds one or more disks such as magnetic disks. When the motor stator 4 is energized, the motor rotor 5 is rotated by electromagnetic force between the motor stator 4 and the motor rotor 5, whereby the disk hub 3 and the shaft member 2 become rotating members and rotate integrally.

  FIG. 2 shows the hydrodynamic bearing device 1 in an enlarged manner. The hydrodynamic bearing device 1 is configured by constituting a housing 7, a bearing sleeve 8 fixed to the housing 7, and the shaft member 2.

  Between the inner peripheral surface 8a of the bearing sleeve 8 and the outer peripheral surface 2a of the shaft member 2, the first radial bearing portion R1 and the second radial bearing portion R2 are provided apart from each other in the axial direction. Further, a thrust bearing portion T1 is formed between the opening end surface (upper end surface) 7d of the housing 7 and the lower end surface 3a of the disk hub (rotor) 3 fixed to the shaft member 2 opposite to the end surface. . For convenience of explanation, the description will proceed with the bottom 7b side of the housing 7 as the lower side and the side opposite to the bottom 7b as the upper side.

  The housing 7 is molded into a bottomed cylindrical shape by, for example, injection molding a resin material in which 2 to 8 wt% of carbon nanotubes as a conductive filler are blended in a liquid crystal polymer (LCP) as a crystalline resin. In the drawing, the housing 7 is illustrated as having a cylindrical side portion 7a and a bottom portion 7b integrally provided at the lower end of the side portion 7a.

  As shown in FIG. 4, for example, a spiral-shaped dynamic pressure groove 7 d 1 is formed on the upper end surface 7 d serving as a thrust bearing surface of the thrust bearing portion T 1. The dynamic pressure groove 7d1 is formed when the housing 7 is injection molded. That is, a groove mold for forming the dynamic pressure groove 7d1 is processed in a required portion of the mold for forming the housing 7 (a portion for forming the upper end surface 7d), and the shape of the groove mold is changed during the injection molding of the housing 7. By transferring to the upper end surface 7 d of the housing 7, the dynamic pressure groove 7 d 1 can be molded simultaneously with the molding of the housing 7.

  In addition, the housing 7 includes a tapered outer wall 7e that gradually increases in diameter upward on the outer periphery of the upper portion thereof. Between the tapered outer wall 7e and the inner wall 3b1 of the flange 3b provided on the disk hub 3, a tapered sealing space S that gradually decreases upward is formed. The seal space S communicates with the outer diameter side of the thrust bearing gap of the thrust bearing portion T1 when the shaft member 2 and the disk hub 3 are rotated.

  The shaft member 2 is formed in a shaft shape having the same diameter with a metal material such as stainless steel. The disk hub 3 is fixed to the shaft member 2 by appropriate means such as press-fitting and adhesion, as well as screwing as shown in the figure.

  The bearing sleeve 8 is formed in a cylindrical shape with a porous body made of sintered metal, for example, a sintered metal porous body mainly composed of copper, and is formed at a predetermined position on the inner peripheral surface 7c of the housing 7 by, for example, ultrasonic welding. Fixed to.

  On the inner peripheral surface 8a of the bearing sleeve 8 formed of sintered metal, two upper and lower regions serving as the radial bearing surfaces of the first radial bearing portion R1 and the second radial bearing portion R2 are provided apart in the axial direction. In these two regions, for example, herringbone shaped (or spiral shaped) dynamic pressure grooves 8a1 and 8a2 as shown in FIG. 3 are formed. The upper dynamic pressure groove 8a1 is formed axially asymmetric with respect to the axial center m (the axial center of the upper and lower inclined groove regions), and the axial dimension X1 of the upper region is lower than the axial center m. It is larger than the axial dimension X2 of the side region. Further, one or a plurality of axial grooves 8d1 are formed on the outer peripheral surface 8d of the bearing sleeve 8 over the entire axial length.

  The shaft member 2 is inserted into the inner peripheral surface 8 a of the bearing sleeve 8. When the shaft member 2 and the disk hub 3 are stopped, the lower end surface 2b of the shaft member 2 and the inner bottom surface 7b1 of the housing 7 and the lower end surface 8c of the bearing sleeve 8 and the inner bottom surface 7b1 of the housing 7 are stopped. There are slight gaps between them.

  The internal space of the housing 7 is filled with lubricating oil. That is, the lubricating oil, including the internal pores of the bearing sleeve 8, includes a gap between the inner peripheral surface 8 a of the bearing sleeve 8 and the outer peripheral surface 2 a of the shaft member 2, the lower end surface 8 c of the bearing sleeve 8, and the shaft member 2. A gap between the lower end face 2b of the housing 7 and the inner bottom face 7b1 of the housing 7, an axial groove 8d1 of the bearing sleeve 8, and a gap between the upper end face 8b of the bearing sleeve 8 and the lower end face 3a of the disk hub 3. The thrust bearing portion T1 and the seal space S are filled.

  When the shaft member 2 and the disk hub 3 are rotated, the regions (two upper and lower regions) of the inner peripheral surface 8a of the bearing sleeve 8 are respectively spaced via the outer peripheral surface 2a of the shaft member 2 and the radial bearing gap. Facing each other. Further, the region serving as the thrust bearing surface of the upper end surface 7d of the housing 7 is opposed to the lower end surface 3a of the disk hub 3 through the thrust bearing gap. As the shaft member 2 and the disk hub 3 rotate, the dynamic pressure of the lubricating oil is generated in the radial bearing gap, and the shaft member 2 is rotatable in the radial direction by the oil film of the lubricating oil formed in the radial bearing gap. Non-contact supported. Thus, the first radial bearing portion R1 and the second radial bearing portion R2 that support the shaft member 2 and the disk hub 3 in a non-contact manner so as to be rotatable in the radial direction are configured. At the same time, dynamic pressure of lubricating oil is generated in the thrust bearing gap, and the disk hub 3 is supported in a non-contact manner in the thrust direction by the oil film of lubricating oil formed in the thrust bearing gap. Thus, a thrust bearing portion T1 that supports the shaft member 2 and the disk hub 3 in a non-contact manner so as to be rotatable in the thrust direction is configured.

  As described above, the dynamic pressure groove 8a1 of the first radial bearing portion R1 is formed to be axially asymmetric with respect to the axial center m, and the axial dimension X1 of the upper region from the axial center is the lower region. It is larger than the axial dimension X2. Therefore, when the shaft member 2 and the disk hub 3 are rotated, the lubricating oil pulling force (pumping force) by the dynamic pressure groove 8a1 is relatively larger in the upper region than in the lower region. Due to the differential pressure of the pulling force, the lubricating oil filled in the gap between the inner peripheral surface 8a of the bearing sleeve 8 and the outer peripheral surface 2a of the shaft member 12 flows downward, and the lower end surface of the bearing sleeve 8 The first radial is circulated through a path between the gap 8c and the inner bottom surface 7b1 of the housing 7 → the axial groove 8d1 → the gap between the lower end surface 3a of the disk hub 3 and the upper end surface 8b of the bearing sleeve 8. It is again drawn into the radial bearing gap of the bearing portion R1. In this way, by configuring the lubricating oil to flow and circulate through the gap portion, the lubricating oil pressure in the internal space of the housing 7 and the thrust bearing gap of the thrust bearing portion T1 becomes a negative pressure locally. It is possible to prevent problems such as generation of bubbles accompanying the generation of negative pressure, leakage of lubricating oil and generation of vibration due to the generation of bubbles. Moreover, leakage of the lubricating oil to the outside is more effectively prevented by the capillary force of the seal space S and the pulling force (pumping force) of the lubricating oil by the dynamic pressure groove 7d1 of the thrust bearing portion T1.

  As shown in FIG. 1, a bracket 6 made of a metal, preferably a light alloy such as an aluminum alloy, is bonded and fixed to the outer periphery of the side portion 7 a of the housing 7. The bracket 6 functions as a holding member for holding the housing 7 in a specified position. After bonding, as shown in FIG. 5, the outer periphery 7f of the housing 7 (excluding the tapered outer wall 7e) and the bracket 6 The inner circumference 6a is firmly bonded with an adhesive (dot pattern) filled in the bonding gap 9 (in FIG. 5, the width P of the bonding gap 9 is exaggerated). As the adhesive 9, either a thermosetting adhesive or an anaerobic adhesive can be used, but it is more preferable to use an anaerobic adhesive from the viewpoint of stabilizing the adhesive strength.

  In order to secure the adhesive strength between the housing 7 and the bracket 6, in the present invention, the surface of the housing 7, which is a resin molded product, is subjected to any surface treatment of alkali etching treatment, UV treatment, plasma etching treatment, or metal plating treatment. Has been given. Note that these surface treatments do not necessarily have to be applied to the entire housing 7, and are only required to be applied to at least the bonding portion with the bracket 6.

FIG. 6 shows the results of measuring the adhesive strength after performing alkaline etching treatment, UV treatment, and plasma etching treatment on the surface of the LCP-based housing 7 and bonding and fixing the aluminum alloy bracket 6 (FIG. 6). In the figure, alkali treatment is indicated as “AL treatment” and plasma etching treatment is indicated as “PL treatment”). An anaerobic adhesive TB1355 manufactured by ThreeBond is used as the adhesive, and 1390F manufactured by the same company is used as the primer. The alkali treatment was performed by immersing the housing in a 4% sodium hydroxide solution maintained at 60 ° C. for 1 hour. In addition, the UV treatment was performed under the conditions of wavelength 365 [nm], irradiation intensity 20 [mW / cm ² ], and irradiation time 10 [min] using Harrison Toshiba Lighting Co., Ltd. TOSCURE251. Further, the plasma etching process was performed under the conditions of an O ₂ amount of 50 [cc / min], an electric power of 150 [W], and a time of 2 [min] using PR31 manufactured by Yamato Scientific Co., Ltd. as an apparatus. The bonding area is 90 [mm ² ].

  In addition, FIG. 6 shows, as a comparative example, a processed surface (smooth surface) of a mirror-finished resin after injection molding, a surface roughened by sandpaper on the smooth surface (rough surface A), and a shot surface. The results of bonding the surfaces (rough surface B) injection-molded with a metal mold roughened with the aluminum alloy and measuring the adhesive strength are also described.

  As shown in the measurement results of FIG. 6, in any of the alkali etching treatment, the UV treatment, and the plasma etching treatment, the adhesive force is greatly improved as compared with the rough surfaces A and B of the comparative example. The effectiveness of was confirmed.

  By the way, in the assembly process of the hydrodynamic bearing device 1, when supplying the lubricating oil into the housing 7, the whole assembled unit is immersed in the oil and evacuated, and then returned to the atmospheric pressure to return the lubricating oil. In some cases, a method of filling each gap is used. In this case, since the entire housing 7 is immersed in the lubricating oil, even if the housing 7 is degreased after the oil immersion, the adhesive strength with the bracket may decrease.

  FIG. 7 shows the measurement of the adhesive strength when the housing 7 after each treatment is immersed in oil and the housing 7 and the bracket 6 are bonded and fixed after the degreasing treatment. As is apparent from this measurement result, when oil immersion is performed, not only the rough surfaces A and B, but also a large decrease in adhesive force is observed in UV treatment and plasma etching treatment. High adhesive strength is maintained even after oil immersion. Therefore, when the housing 7 is immersed in the oil supply process inside the housing 7, it is preferable to perform an alkali etching process as a surface treatment of the resin housing 7.

  FIG. 8 shows the measurement results of the adhesive strength when alkali etching is performed under different conditions under the above conditions. As shown in the figure, the adhesive strength decreases as the processing time is shortened. On the other hand, it can be understood that the adhesive strength decreases even when the processing time is increased. From the above verification, it is considered that the adhesive strength reaches a critical value when the alkali etching treatment time is around 1 hour.

  By the way, the motors for various information devices tend to be used in a higher temperature environment with the recent increase in speed and density. In order to cope with this, the hydrodynamic bearing device 1 is also required to have high thermal shock resistance. However, the present inventors have verified that the thermal shock resistance of the adhesive strength is the adhesion between the housing 7 and the bracket 6. It was found that it greatly depends on the width P of the clearance. FIG. 9 shows the measurement results. In the figure, Δ indicates the adhesive strength after thermal shock loading, and ● indicates the adhesive strength before thermal shock loading. As is apparent from the figure, it was found that when the width P (radius amount: see FIG. 5) of the bonding gap 9 exceeds 30 μm, the adhesive strength after the thermal shock load is greatly reduced. Therefore, in order to ensure the thermal shock resistance, it is desirable to set the adhesion gap 9 between the outer periphery 7f of the housing 7 and the inner periphery 6a of the bracket 6 to 30 μm or less (5 μm or more).

  Although the present invention has been described based on one embodiment, the present invention is not limited to the fluid dynamic bearing device illustrated in FIG. 1 to FIG. 3, and may be various as long as it has a resin housing 7 and a metal bracket 6. This type of fluid dynamic bearing device can be applied. FIG. 10 shows an example thereof. The shaft member 2 is composed of a shaft portion 2c and a flange portion 2d projecting to the outer diameter side, and one end surface of the flange portion 2d and the end surface of the bearing sleeve 8 facing this end surface. The first thrust bearing portion T1 and the second thrust bearing portion are formed by forming a thrust bearing surface on one of the other end surface of the flange portion 2d and the bottom portion 7b of the flange portion 2d facing the flange portion 2d. T2 is vertically spaced apart (radial bearing portions R1 and R2 are not shown). Similarly in this embodiment, the outer peripheral surface of the resin housing 7 is bonded and fixed to the inner peripheral surface of the metal bracket 6, but by subjecting the outer peripheral surface of the housing 7 before bonding to surface treatment such as alkali etching, Alternatively, a high adhesive strength can be obtained by setting the adhesive clearance to 30 μm or less. Contact-type pivot bearings may be used as the thrust bearing portions T1 and T2.

  In the above description, the bracket 6 is made of metal, but the bracket 6 can be made of a resin molded product. In this case, if the housing 7 is made of a metal such as a soft metal warehouse, it is necessary to perform the surface treatment on the bonding portion on the surface of the bracket 6. When the housing 7 is also made of resin, it is desirable to perform the surface treatment on the bonding portion of both members. However, if sufficient adhesive force is obtained, only the bonding portion of one of the members is the above. A surface treatment may be applied.

It is sectional drawing of the spindle motor for information devices incorporating the dynamic pressure bearing apparatus concerning this invention. It is sectional drawing of the said dynamic pressure bearing apparatus. It is sectional drawing of the bearing sleeve used with the said dynamic pressure bearing apparatus. It is the figure which looked at the housing from the B direction of FIG. It is sectional drawing of the radial direction which expanded the adhesion part of a housing and a bracket. It is a figure which shows the measurement result of adhesive strength. It is a figure which shows the measurement result of the adhesive strength after oil immersion. It is a figure which shows the measurement result of the adhesive strength when the processing time of an alkali etching process is varied. It is a figure which shows the measurement result of the relationship between an adhesion clearance gap and adhesive strength. It is sectional drawing of the spindle motor for information devices incorporating the dynamic pressure bearing apparatus concerning other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dynamic pressure bearing apparatus 2 Shaft member 3 Disc hub 4 Stator 5 Rotor 6 Bracket 7 Housing 7d1 Dynamic pressure groove 8 Bearing sleeve 8a1, 8a2 Dynamic pressure groove 9 Adhesive clearance R1, R2 Radial bearing part T1, T2 Thrust bearing part

Claims (10)

A housing, a bearing sleeve fixed inside the housing, a rotating member rotating with respect to the housing and the bearing sleeve, and a hydrodynamic action of fluid generated in a radial bearing gap between the bearing sleeve and the rotating member. In a hydrodynamic bearing device comprising a radial bearing portion that supports a rotating member in a radial direction in a non-contact manner, and a holding member that holds the housing by adhesion to the housing.
At least one of the housing and the holding member is a resin molded product, and at least an adhesive portion of the resin molded product is subjected to a surface treatment for strengthening an adhesive force with a counterpart member. Hydrodynamic bearing device.   2. The hydrodynamic bearing device according to claim 1, wherein the surface treatment removes the skin layer on the surface.   The hydrodynamic bearing device according to claim 2, wherein the surface treatment is an alkali etching treatment.   The hydrodynamic bearing device according to claim 1, wherein the surface treatment activates the surface.   The hydrodynamic bearing device according to claim 4, wherein the surface treatment is either UV treatment or plasma etching treatment.   2. The hydrodynamic bearing device according to claim 1, wherein the surface treatment forms a metal plating layer on the surface.   The hydrodynamic bearing device according to claim 1, wherein an adhesion clearance between the housing and the holding member is 30 μm or less. A housing, a bearing sleeve fixed inside the housing, a rotating member rotating with respect to the housing and the bearing sleeve, and a hydrodynamic action of fluid generated in a radial bearing gap between the bearing sleeve and the rotating member. In a hydrodynamic bearing device comprising a radial bearing portion that supports a rotating member in a radial direction in a non-contact manner, and a holding member that holds the housing by adhesion to the housing.
A hydrodynamic bearing device in which a bonding clearance between the housing and the holding member is 30 μm or less.   The hydrodynamic bearing device according to claim 1, wherein the holding member is a bracket having a motor stator attachment portion. A motor comprising the fluid dynamic bearing device according to claim 9, a motor stator attached to a bracket, and a motor rotor attached to a rotating member.