JP4689567B2 - Method for manufacturing hydrodynamic bearing device - Google Patents

Description

  The present invention relates to a method for manufacturing a hydrodynamic bearing device in which an inner member is rotatably supported by a lubricating film formed in a bearing gap.

  Due to its high rotational accuracy and quietness, the hydrodynamic bearing device is an information device, for example, a magnetic disk drive device such as HDD, an optical disk drive device such as CD-ROM, CD-R / RW, DVD-ROM / RAM, MD, MO, etc. Suitable for small motors such as fan motors used for spindle motors such as magneto-optical disk drive devices, etc., polygon scanner motors for laser beam printers (LBP), color wheels for projectors, cooling fans for electrical equipment, etc. It can be used.

  For example, a hydrodynamic bearing device disclosed in Patent Document 1 includes a shaft member, a bearing sleeve in which a shaft member is inserted on the inner periphery, a housing holding the bearing sleeve on the inner periphery, an inner peripheral surface of the bearing sleeve, and a shaft. And a radial bearing gap formed between the outer peripheral surface of the member, and the shaft member is rotatably supported by an oil film generated in the radial bearing gap.

  In this hydrodynamic bearing device, after irradiating the inner and outer peripheral surfaces of the housing with ultraviolet rays, a bearing sleeve is bonded to the inner peripheral surface and a bracket is fixed to the outer peripheral surface. By irradiating with ultraviolet rays, the wettability of the inner peripheral surface and the outer peripheral surface can be improved and the adhesiveness of the adhesive can be improved, so that the adhesive strength between the housing and the bearing sleeve or the bracket can be improved.

JP 2005-344793 A

  However, in order to uniformly irradiate the cylindrical surface such as the outer peripheral surface and the inner peripheral surface of the housing with ultraviolet rays, for example, it is necessary to irradiate from a plurality of light sources or to rotate while rotating the housing. The process has become complicated, leading to high costs and reduced production efficiency.

  The subject of this invention is providing the manufacturing method of the hydrodynamic bearing apparatus which can irradiate an ultraviolet-ray easily also to a cylindrical surface.

In order to solve the above problems, the present invention comprises an inner member having a shaft portion, an outer member having a shaft portion inserted into the inner periphery thereof, and a radial bearing gap facing the outer peripheral surface of the shaft portion. A method for manufacturing a hydrodynamic bearing device in which an inner member is rotatably supported by a generated oil film, and ultraviolet rays reflected by a reflecting surface on an outer peripheral surface of an outer member serving as a fixing surface for bonding and fixing other members Is characterized in that the wettability is improved by uniformly irradiating.

  Thus, in this invention, the ultraviolet-ray reflected by the reflective surface is irradiated to at least one part of the fixing surface for adhesive-fixing another member among outer members. Thereby, even if a fixed surface is a cylindrical surface, it is not necessary to rotate a some light source and an outer member, and it can irradiate a ultraviolet-ray uniformly by a simple method.

  In such a hydrodynamic bearing device, in order to prevent leakage of lubricating oil held inside, a seal space connected from the radial bearing gap to the atmosphere release side is provided, and an oil repellent agent is provided on the atmosphere release side of the seal space. May be applied. When the surface to which the oil repellent agent is applied is irradiated with ultraviolet rays, the oil repellency effect is reduced. Therefore, when the ultraviolet rays are irradiated, it is necessary to shield the surface to which the oil repellent agent is applied from the ultraviolet rays. When this shielding is performed with a jig having a reflecting surface, the apparatus can be simplified.

  In general, the intensity of ultraviolet rays received by a surface irradiated with ultraviolet rays (hereinafter referred to as an irradiation surface) is affected by the irradiation angle of ultraviolet rays with respect to the irradiation surface and the path of ultraviolet rays from the light source to the irradiation surface (hereinafter referred to as irradiation path). For example, as shown in FIG. 8, when the reflecting surface 100a is provided on the light source P side, the irradiation angle θ1 of the ultraviolet ray L1 irradiated to the outer peripheral surface 107a of the bottomed cylindrical housing 107 through the reflecting surface 100a is Since it is relatively small, the intensity of the ultraviolet ray L1 irradiated to the outer peripheral surface 107a is relatively weak. On the other hand, since the irradiation angle θ2 of the ultraviolet ray L2 directly irradiated to the bottom surface 107b of the housing 107 without passing through the reflecting surface 100a is relatively large, the intensity of the ultraviolet ray L2 irradiated to the bottom surface 107b is relatively strong. As described above, since the intensity of the ultraviolet rays to be irradiated differs depending on the place, the bottom surface 107b having a high irradiation intensity when irradiated for a long time or with a strong ultraviolet ray so as to irradiate the outer peripheral surface 107a with a low irradiation intensity. Excessive ultraviolet rays are irradiated to the bottom surface 107b, and the bottom surface 107b may be deformed due to a temperature rise, or in the worst case, may melt.

  On the other hand, if the reflecting surface 100a having a large inner diameter is used to increase the irradiation angle θ1 of the ultraviolet ray L1 to the outer peripheral surface 107a, the difference in the irradiation path between the ultraviolet ray L1 and the ultraviolet ray L2 becomes large. The difference in the intensity of the irradiated ultraviolet rays increases and causes the same problems as described above.

  In view of this point, by providing the reflective surface close to the outer member, for example, on the outer periphery or the inner periphery of the outer member, ultraviolet rays that are irradiated through the reflective surface and ultraviolet rays that are irradiated without passing through the reflective surface. Therefore, the difference in the intensity of the ultraviolet rays applied to the respective irradiation surfaces can be reduced. Therefore, it is possible to prevent the outer member from being deformed or melted due to the difference in intensity of the irradiated ultraviolet rays.

  In this manufacturing method, when the reflective surface is provided on the outer periphery of the outer member, the outer peripheral surface of the outer member can be uniformly irradiated with ultraviolet rays. Further, when the reflecting surface is provided on the inner periphery of the outer member, the inner peripheral surface of the outer member can be uniformly irradiated with ultraviolet rays.

  As described above, according to the method for manufacturing a hydrodynamic bearing device of the present invention, it is possible to easily irradiate the cylindrical surface with ultraviolet rays.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 conceptually shows one configuration example of a spindle motor for information equipment incorporating a fluid dynamic bearing device (dynamic pressure bearing device) 1 to which the manufacturing method of the present invention is applied. This spindle motor is used in a disk drive device such as an HDD, and is opposed to the hydrodynamic bearing device 1 that rotatably supports the shaft member 2 to which the disk hub 3 is attached via a radial gap, for example. The stator coil 4 and the rotor magnet 5 and the motor bracket 6 are provided. The stator coil 4 is attached to the outer periphery of the motor bracket 6, and the rotor magnet 5 is attached to the outer peripheral side inner peripheral surface of the disk hub 3. The hydrodynamic bearing device 1 is fixed to the inner periphery of the motor bracket 6. The disk hub 3 holds one or a plurality (two in the present embodiment) of a disk-shaped information recording medium (hereinafter simply referred to as a disk) D such as a magnetic disk. In the spindle motor configured as described above, when the stator coil 4 is energized, the rotor magnet 5 is rotated by the electromagnetic force generated between the stator coil 4 and the rotor magnet 5. The disk D held by the hub 3 rotates integrally with the shaft member 2.

  FIG. 2 shows the hydrodynamic bearing device 1. The hydrodynamic bearing device 1 includes a shaft member 2 as an inner member, a bearing sleeve 8 in which the shaft member 2 is inserted on the inner periphery, and a housing 7 as an outer member in which the bearing sleeve 8 is fixed on the inner peripheral surface. Prepare mainly. For convenience of explanation, the side closed by the bottom 7b of the cup-shaped housing 7 will be described below, and the opened side will be described as the upper side.

  The shaft member 2 is formed in a cylindrical shape from a metal material such as SUS steel, and includes a shaft portion 2a and a flange portion 2b provided at the lower end of the shaft portion 2a. The shaft portion 2a and the flange portion 2b may be formed of the same material, or may be a hybrid structure in which, for example, the flange portion 2b is formed of a resin material and is provided integrally with the shaft portion 2a.

  The bearing sleeve 8 is formed in a cylindrical shape with a porous body of sintered metal whose main component is copper, for example. In addition, the bearing sleeve 8 can be formed of other metals, resins, ceramics, or the like.

  As shown in FIG. 3A, for example, as shown in FIG. 3A, a plurality of dynamic pressure grooves 8a1 and 8a2 are arranged in a herringbone shape on the entire inner surface 8a of the bearing sleeve 8 or a partial cylindrical region. The two regions are formed at two positions apart in the axial direction. When the shaft member 2 rotates, a radial bearing gap between radial bearing portions R1 and R2 described later is formed between the formation region of the dynamic pressure grooves 8a1 and 8a2 and the outer peripheral surface 2a1 of the shaft portion 2a (see FIG. 2). ).

  On the outer peripheral surface 8b of the bearing sleeve 8, one or more grooves 8e extending in the axial direction are formed over the entire length in the axial direction. In this embodiment, three axial grooves 8e are formed at equal intervals in the circumferential direction. These axial grooves 8e constitute a fluid flow path 10b for lubricating oil between the inner circumferential surface 7a1 of the housing 7 facing the bearing sleeve 8 in a state where the bearing sleeve 8 is fixed to the inner circumference of the housing 7 (see FIG. 2). ). These axial grooves 8e are formed at the same time as the green compact forming of the bearing sleeve 8 main body by providing a portion corresponding to the axial groove 8e in advance in a green compact forming die forming the main body of the bearing sleeve 8 for example. be able to.

  As shown in FIG. 3B, a region where a plurality of dynamic pressure grooves 8c1 are arranged in a spiral shape is formed on the entire lower surface 8c of the bearing sleeve 8 or a partial annular region. When the shaft member 2 rotates, a thrust bearing gap of a first thrust bearing portion T1 described later is formed between the formation region of the dynamic pressure groove 8c1 and the upper end surface 2b1 of the flange portion 2b (see FIG. 2).

  As shown in FIG. 3A, a circumferential groove 8d1 having a V-shaped cross section is formed over the entire circumference of the upper end surface 8d of the bearing sleeve 8 at a substantially central portion in the radial direction. One or a plurality of radial grooves 8d2 are formed in the inner diameter side region of the upper end face 8d defined by the circumferential groove 8d1. With the seal portion 9 in contact with the bearing sleeve 8, the gap between the outer diameter side region of the lower end surface 9b of the seal portion 9 and the upper end surface 8d of the bearing sleeve 8, the circumferential groove 8d1, and the radial direction The groove 8d2 constitutes the fluid flow path 10c (see FIG. 2).

  The housing 7 is formed in a cup shape having a side portion 7a and a bottom portion 7b. On the entire or partial annular region of the inner bottom surface 7b1 of the housing 7, a region in which a plurality of dynamic pressure grooves are arranged in a spiral shape is formed (not shown). When the shaft member 2 rotates, a thrust bearing gap of a second thrust bearing portion T2 described later is formed between the dynamic pressure groove forming region and the lower end surface 2b2 of the flange portion 2b (see FIG. 2).

  The housing 7 is made of a crystalline resin such as liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyphenyl sulfone (PPSU), polyether sulfone (PES), polyetherimide ( Injection molding with a resin composition based on an amorphous resin such as PEI). Examples of the resin composition forming the housing 7 include fibrous fillers such as glass fibers, whisker-like fillers such as potassium titanate, scaly fillers such as mica, carbon fibers, carbon black, graphite, carbon A material in which an appropriate amount of a fibrous or powdery conductive filler such as nanomaterials or various metal powders is blended with the base resin according to the purpose can be used.

  The seal portion 9 is formed of, for example, a metal material or a resin material, and is a means such as press-fitting, bonding, press-fitting (referred to as press-fitting adhesion), welding, welding, or the like to the inner periphery of the upper end of the side portion 7a of the housing 7 It is fixed with. In this embodiment, the seal portion 9 is fixed in a state where the lower end surface 9b of the seal portion 9 is in contact with the upper end surface 8d of the bearing sleeve 8 (see FIG. 2).

  A taper surface is formed on the inner peripheral surface 9a of the seal portion 9, and the radial dimension gradually increases between the taper surface and the outer peripheral surface 2a1 of the shaft portion 2a facing the taper surface. A seal space S that expands and is connected to the open side of the radial bearing gap is formed. Lubricating oil is injected into the internal space of the housing 7 sealed by the seal portion 9, and the inside of the housing 7 is filled with the lubricating oil (a dotted area in FIG. 2). In this state, the oil level of the lubricating oil is maintained within the range of the seal space S. Further, an oil repellent is applied to the atmosphere opening side of the seal space S, specifically, to the upper end surface 9c of the seal portion 9 in order to surely prevent oil leakage.

  Lubricating oil is filled in the inside of the hydrodynamic bearing device 1 having the above configuration. Various lubricants can be used as the lubricant, but the lubricant provided in the fluid dynamic bearing device for a disk drive device such as an HDD is considered in consideration of temperature changes during use or transportation. As the base oil, an ester-based lubricating oil excellent in low evaporation rate and low viscosity, for example, dioctyl sebacate (DOS), dioctyl azelate (DOZ) and the like can be suitably used.

  As described above, after the assembly and lubrication of the dynamic pressure bearing device 1 are completed, the outer peripheral surface 7a2 of the housing 7 serving as a fixing surface for bonding and fixing the bracket 6 is irradiated with ultraviolet rays, whereby the dynamic pressure bearing device. 1 is completed. Hereinafter, the process of irradiating the outer peripheral surface 7a2 of the housing 7 with ultraviolet rays will be described.

  The jig 11 used in this ultraviolet irradiation process is made of, for example, metal, and includes a spherical reflecting surface 11a and a loading surface 11b on which the hydrodynamic bearing device 1 is placed as shown in FIG. . The reflecting surface 11a is mirror-finished in order to increase the reflection efficiency of ultraviolet rays. By placing the hydrodynamic bearing device 1 on the mounting surface 11b of the jig 11 so that the upper end surface 9c of the seal portion 9 and the upper end surface 7a3 of the housing 7 face each other, the upper end surface 9c of the seal portion 9 is mounted. The applied oil repellent is shielded from ultraviolet rays. At this time, the reflecting surface 11 a is disposed on the outer periphery of the housing 7.

  In this state, the ultraviolet light irradiated from the light source P coaxial with the dynamic pressure bearing device 1 is reflected on the reflecting surface 11 a and is irradiated on the outer peripheral surface 7 a 2 of the housing 7. Thereby, it is possible to uniformly irradiate the outer peripheral surface 7a2 of the housing 7 with ultraviolet rays without using a plurality of light sources or rotating the housing 7.

  Further, as shown in FIG. 4, by providing the reflecting surface 11a close to the outer peripheral surface 7a2 of the housing 7, the irradiation angle θ1 of the ultraviolet ray L1 irradiated through the reflecting surface 11a to the outer peripheral surface 7a2 of the housing 7 is provided. And the difference between the irradiation angle θ2 of the ultraviolet ray L2 applied to the bottom surface 7b2 of the housing 7 without passing through the reflecting surface 11a, and the difference in the irradiation path between the ultraviolet ray L1 and the ultraviolet ray L2 can be reduced. It can be made relatively small. Thereby, since the difference in the intensity of the ultraviolet rays applied to the outer peripheral surface 7a2 and the bottom surface 7b2 of the housing 7 is reduced, the problem that the bottom surface 7b2 of the housing 7 is deformed or melted can be avoided.

  Thus, by irradiating the outer peripheral surface 7a2 of the housing 7 with ultraviolet rays, the wettability of the outer peripheral surface 7a2 of the housing 7 is improved and the adhesiveness of the adhesive is improved. It is possible to improve the adhesive strength. In particular, when the housing 7 is formed of a resin as in this embodiment, since the adhesive effect of an adhesive is generally inferior to that of a metal or the like, an improvement in adhesiveness due to ultraviolet irradiation is effective.

  In general, when the surface coated with the oil repellent is irradiated with ultraviolet rays, the oil repellent effect is reduced. In this embodiment, the upper end surface 9c of the seal portion 9 coated with the oil repellent is the loaded value of the jig 11. Since it is shielded from ultraviolet rays by facing the surface 11b, the oil repellent effect by the oil repellent agent can be maintained.

  In general, when the surface irradiated with ultraviolet rays comes into contact with the lubricating oil, the effect of improving wettability due to ultraviolet irradiation is reduced. Therefore, lubrication of the inside of the hydrodynamic bearing device 1 is performed by a method in which the lubricating oil comes into contact with the outer peripheral surface 7a2 of the housing 7, for example, a method in which the hydrodynamic bearing device 1 is immersed in the lubricating oil in a reduced pressure environment. In the case of carrying out with, as described above, it is desirable to irradiate ultraviolet rays after oiling. On the other hand, lubrication of the hydrodynamic bearing device 1 is performed by a method in which the lubricating oil does not come into contact with the outer peripheral surface 7a2 of the housing 7, for example, a method of dropping oil into the opening of the hydrodynamic bearing device 1 in a reduced pressure environment (so-called dripping oil impregnation). ), It may be lubricated after the outer peripheral surface 7a2 of the housing 7 is irradiated with ultraviolet rays.

  In the hydrodynamic bearing device 1 having the above-described configuration, when the shaft member 2 rotates, the hydrodynamic groove 8a1 and 8a2 formation region of the inner peripheral surface 8a of the bearing sleeve 8 is interposed between the outer peripheral surface 2a1 of the shaft portion 2a and the radial bearing gap. opposite. As the shaft member 2 rotates, the lubricating oil in the radial bearing gap is pushed toward the axial center m of the dynamic pressure grooves 8a1 and 8a2, and the pressure rises. By such dynamic pressure action of the dynamic pressure grooves 8a1 and 8a2, the first radial bearing portion R1 and the second radial bearing portion R2 that support the shaft member 2 in a non-contact manner in the radial direction are configured.

  At the same time, the thrust bearing gap between the region where the dynamic pressure groove 8c1 is formed on the lower end surface 8c of the bearing sleeve 8 and the upper end surface 2b1 of the flange portion 2b facing this, and the dynamic pressure of the upper end surface 7b1 of the housing 7 An oil film of lubricating oil is formed in the thrust bearing gap between the groove forming region and the lower end surface 2b2 of the flange portion 2b facing the groove forming region by the dynamic pressure action of each dynamic pressure groove. The pressure of these oil films forms a first thrust bearing portion T1 and a second thrust bearing portion T2 that support the shaft member 2 in a non-contact manner in the thrust direction.

  Further, the diameter formed in the step portion 7 d of the housing 7 is between the thrust bearing gap of the thrust bearing portions T 1 and T 2 located inside the lower end of the housing 7 and the seal space S formed on the opening side of the housing 7. A fluid flow path 10 a formed by the directional groove and the lower end surface 8 c of the bearing sleeve 8, a fluid flow path 10 b formed by the axial groove 8 e formed in the outer peripheral surface 8 b of the bearing sleeve 8, and the seal portion 9. A communication state is established via a fluid flow path 10 c constituted by the lower end face 9 b and the upper end face 8 d of the bearing sleeve 8. According to this, for example, the shaft (2) is stably non-contacted in the thrust direction while avoiding a situation in which the fluid (lubricating oil) pressure on the thrust bearing portions T1, T2 side is excessively increased or decreased for some reason. It becomes possible to support.

  Further, in this embodiment, the dynamic pressure groove 8a1 of the first radial bearing portion R1 is formed to be axially asymmetric (X1> X2) with respect to the axial center m (see FIG. 3). At the time of rotation, 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. Then, 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 2a1 of the shaft portion 2a flows downward, and the first thrust bearing portion T1 It circulates through the path of thrust bearing gap → fluid flow path 10a → fluid flow path 10b → fluid flow path 10c, and is again drawn into the radial bearing gap of the first radial bearing portion R1. In this way, by configuring the lubricating oil to flow and circulate in the internal space of the housing 7, the pressure balance inside the bearing is properly maintained. Thereby, generation | occurrence | production of the bubble accompanying the negative pressure generation | occurrence | production of lubricating oil can be prevented, and problems, such as the leakage of lubricating oil and generation | occurrence | production of a vibration accompanying this, can be eliminated.

  The embodiment of the present invention is not limited to the above. In the following description, portions having the same functions as those in the above embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the ultraviolet irradiation step, the spherical reflecting surface 11a is used in the above description. However, the present invention is not limited to this. For example, as shown in FIG. 5, a conical reflecting surface 11c may be used. In the above, the reflecting surface 11a (11c) and the fixing surface 11b are provided on the jig 11. For example, the reflecting surface is provided on a reflecting mirror formed separately from the jig having the fixing surface. (Not shown).

  Further, the case where the outer peripheral surface 7a2 of the housing 7 is irradiated with ultraviolet rays has been described above. However, when the inner peripheral surface 7a1 of the housing 7 and the bearing sleeve 8 are bonded and fixed, the inner peripheral surface 7a1 is irradiated with ultraviolet rays. May be. In this case, as shown in FIG. 6, when the reflecting mirror 12 having the spherical reflecting surface 12a is arranged on the inner periphery of the housing 7, the ultraviolet rays irradiated from above the housing 7 are reflected by the reflecting surface 12a and the housing. 7 is irradiated to the inner peripheral surface 7a1. The shape of the reflecting surface is not limited to a spherical shape, and the reflecting surface may be reflected by a conical reflecting surface 12b as shown in FIG.

  The configuration of the hydrodynamic bearing device to which the manufacturing method of the present invention is applied is not limited to the above. Although the case where the housing 7 is formed of resin is shown above, the present invention is not limited thereto, and may be formed of metal, for example. Even when the metal housing is irradiated with ultraviolet rays, the wettability is improved in the same manner as described above, so that the adhesion can be improved.

  In the above description, the housing 7 is an outer member, and the outer peripheral surface and inner peripheral surface are irradiated with ultraviolet rays. For example, the bearing sleeve 8 is an outer member, and the outer peripheral surface 8b is irradiated with ultraviolet rays. Also good. In particular, when the bearing sleeve 8 is formed of resin, it is effective to improve the wettability by irradiating the outer peripheral surface 8b serving as a fixed surface with the housing 7 with ultraviolet rays.

  Moreover, although the cup-shaped housing 7 is used in the above, the housing opened at both ends can also be used. At this time, the one end opening of the housing may be closed with a bottom formed separately. Or you may form a seal space in the opening part of the both ends of a housing.

  In the above description, the housing 7 and the bearing sleeve 8 are formed separately, but they may be integrally formed.

  The shapes of the dynamic pressure generating portions of the radial bearing portions R1, R2 and the thrust bearing portions T1, T2 are not limited to the above. For example, as the dynamic pressure generating portions of the radial bearing portions R1, R2, spiral dynamic pressure grooves and A step bearing, a multi-arc bearing, or the like can also be formed. In addition, a herringbone-shaped dynamic pressure groove, a step bearing, a wave bearing, or the like can be formed as the dynamic pressure generating portion of the thrust bearing portions T1 and T2.

  In the above description, the dynamic pressure generating portions of the radial bearing portions R1 and R2 are formed on the inner peripheral surface 8a of the bearing sleeve 8. The inner peripheral surface 8a is a cylindrical surface and is opposed to this through a radial bearing gap. A dynamic pressure generating portion may be formed on the outer peripheral surface 2a1 of the shaft portion 2a. Further, in the above, the dynamic pressure generating portions of the thrust bearing portions T1 and T2 are formed on the lower end surface 8c of the bearing sleeve 8 and the inner bottom surface 7b1 of the housing 7, but these surfaces are opposed to each other through the thrust bearing gap. You may form in the upper end surface 2b1 and the lower end surface 2b2 of the flange part 2b to do.

  Further, the shaft member 2 may have a shape without the flange portion 2b. At this time, a thrust bearing gap of the thrust bearing portion T2 is formed between the lower end surface of the shaft member 2 and the inner bottom surface 7b1 of the housing 7. Alternatively, the shaft member 2 is supported in the thrust direction by providing a spherical convex portion at the lower end portion of the shaft member 2 and forming a so-called pivot bearing with the lower end of the convex portion and the inner bottom surface 7b1 of the housing 7. You can also.

  Further, by making both the outer peripheral surface 2a1 of the shaft portion 2a and the inner peripheral surface 8a of the bearing sleeve 8 that face each other through the radial bearing gap into a cylindrical surface, the radial bearing portion can also be configured by a so-called round bearing. .

  The hydrodynamic bearing device 1 as described above is not limited to a disk drive device such as an HDD, but a spindle motor for driving a magneto-optical disk of an optical disk, a small motor for information equipment used under high-speed rotation, a laser beam. It can also be used for supporting a rotating shaft in a polygon scanner motor of a printer or a fan motor used in an electric device or the like.

It is sectional drawing of the spindle motor incorporating the dynamic pressure bearing apparatus. 1 is a cross-sectional view of a fluid dynamic bearing device 1. FIG. It is (a) sectional drawing of the bearing sleeve 8, and (b) bottom view. FIG. 6 is a cross-sectional view showing a process of irradiating the outer peripheral surface of the housing 7 with ultraviolet rays. 12 is a cross-sectional view showing another example of a process of irradiating the outer peripheral surface of the housing 7 with ultraviolet rays. FIG. FIG. 6 is a cross-sectional view showing a process of irradiating ultraviolet rays onto the inner peripheral surface of the housing 7. FIG. 10 is a cross-sectional view showing another example of the process of irradiating the inner peripheral surface of the housing 7 with ultraviolet rays. It is sectional drawing which shows the conventional process of irradiating the housing 7 with ultraviolet rays.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dynamic pressure bearing apparatus 2 Shaft member 2a Shaft part 7 Housing 8 Bearing sleeve 9 Seal part 11 Jig 11a, 11c Reflective surface 12 Reflective mirror 12a, 12b Reflective surface L1, L2 Ultraviolet light P Light source θ1, θ2 Radiation angle R1, R2 Radial Bearing portion T1, T2 Thrust bearing portion S Seal space

Claims (4)

An inner member having a shaft portion, an outer member having the shaft portion inserted into the inner periphery, and a radial bearing gap facing the outer peripheral surface of the shaft portion are rotatably supported by an oil film generated in the radial bearing gap. A method for manufacturing a hydrodynamic bearing device, comprising:
A method of manufacturing a hydrodynamic bearing device, wherein the wettability is improved by uniformly irradiating an outer peripheral surface of an outer member serving as a fixing surface for bonding and fixing another member with ultraviolet rays reflected by a reflecting surface.   2. A seal space connected from the radial bearing gap to the atmosphere opening side is provided, an oil repellent agent is applied to the atmosphere opening side of the seal space, and the application surface of the oil repellent agent is shielded from ultraviolet rays by a jig having a reflection surface. A manufacturing method of the fluid dynamic bearing device as described.   The method of manufacturing a hydrodynamic bearing device according to claim 1, wherein the reflecting surface is disposed on the outer periphery of the outer member. An inner member having a shaft portion, an outer member having the shaft portion inserted into the inner periphery, and a radial bearing gap facing the outer peripheral surface of the shaft portion are rotatably supported by an oil film generated in the radial bearing gap. A method for manufacturing a hydrodynamic bearing device, comprising:
The manufacturing method of the hydrodynamic bearing apparatus which irradiates the ultraviolet-ray reflected by the reflective surface arrange | positioned in the inner periphery of an outer member to at least one part of the fixing surface for adhesively fixing another member among outer members .

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