JP2006200573A - Fluid bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor having a bearing life elongated by securely filling an axial abutting face with an adhesive while preventing the entry of lubricating fluid to the axial abutting face. <P>SOLUTION: A recessed portion 34 provided on the outer periphery of a thrust plate 30 is fixed to abut on an outside lower end face 15 and a peripheral wall 16 of a sleeve 10. The adhesive is filled into an adhesive sump portion 90 formed between a chamfered portion 32 of the thrust plate 30 and the peripheral wall 16 of the sleeve 10. The recessed portion 34 forms an air escapeway in a gap 80, whereby the adhesive smoothly enters therein to be filled in an abutting face between the thrust plate 30 and the outside lower end face 15 of the sleeve 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hydrodynamic bearing device, a spindle motor using the hydrodynamic bearing device, and a recording disk driving device using the spindle motor.

  In recent years, recording disk drive devices have come to be used in portable devices, and there has been a demand for higher accuracy, smaller size, and improved impact resistance of recording disk drive devices. Accordingly, spindle motors used in recording disk drive devices are also required to have higher accuracy, smaller size, and improved impact resistance. In order to satisfy these requirements, it is becoming more and more popular to shift the spindle motor bearings from conventional ball bearings to fluid dynamic pressure bearings.

  FIG. 11 is an axial sectional view of a fluid dynamic pressure bearing. FIG. 12 is an enlarged view of a portion E in FIG.

  Referring to FIG. 11, sleeve A has a substantially hollow cylindrical shape, and shaft B is inserted into the hollow portion through a minute gap in the radial direction and is rotatably supported. The shaft B has a cylindrical shape, and is opposed to the thrust plate C in the axial direction on the lower side in the axial direction with a small gap. A housing D is fixed to the outer peripheral surface of the sleeve A, and a thrust plate C is accommodated on the lower side in the axial direction. These minute gaps are filled with a lubricating fluid. An adhesive is used to seal the lubricating fluid between the thrust plate C and the housing D (see Patent Document 1 as an example of the conventional fluid dynamic bearing as described above).

JP 2002-61641 A

  In order to seal the lubricating fluid between the thrust plate C and the housing D, it is essential to seal the axial contact surface between the thrust plate C and the housing D with an adhesive. However, referring to FIG. 12, the axial contact surface between the thrust plate C and the housing D is in close contact, and exists in the gap F formed at the intersection of the axial contact surface and the radial contact surface. There is no escape for air. However, in general, air escapes through a slight gap due to the surface roughness of the member. However, when it comes into contact with an axial contact surface such as a load due to caulking or weight, there is no possibility of air escape. There is sex. For this reason, even if an attempt is made to fill the gap F with the adhesive, the air present in the gap F pushes the adhesive back, so that the adhesive may not enter the gap F. In addition, if the adhesive seal on the contact surface is insufficient, the air in the gap F passes through the contact surface and replaces the lubricating fluid, and the air moves into the bearing, which can seriously affect the motor rotation operation. There is sex. As a result, there is a possibility of affecting the read / write to the recording disk. Accordingly, it is an object of the present invention to provide a motor with a reliable bearing life by reliably filling the axial contact surface with an adhesive to prevent penetration of the lubricating fluid into the axial contact surface.

  According to the first aspect of the present invention, a rotating member, a stationary member, a bearing cavity formed in the stationary member and in which the rotating member is rotatably inserted, and the bearing cavity at one end side of the stationary member An annular surface formed by bending outward in the radial direction, a peripheral wall surface that is formed to rise in one end direction at an outer edge portion of the annular surface, and surrounds the annular surface from the radially outer side, and one end of the stationary member A small gap formed on the disk-shaped member, which is disposed on the side and abuts against the annular surface and the peripheral wall surface and closes the bearing cavity, and the outer peripheral surface of the rotating member and the inner peripheral surface of the bearing cavity. And a fluid bearing that fills the minute gap, a hydrodynamic bearing portion composed of the outer peripheral surface of the rotating member, the inner peripheral surface of the bearing cavity, and the lubricating fluid, and between the peripheral wall surface and the disk-shaped member At least the peripheral wall surface and the disc-shaped portion In the hydrodynamic bearing device having an adhesive that seals between the outer peripheral surfaces of the stationary member, formed on at least one of the contact surfaces of the annular surface of the stationary member and the disk-shaped member, It has at least one recessed part which spreads in the radial direction.

  According to a second aspect of the present invention, according to the first aspect, the recess communicates the peripheral wall surface with the bearing cavity.

  According to a third aspect of the present invention, according to any one of the first and second aspects, the concave portion is continuously formed with a small gap in a radial direction.

  According to a fourth aspect of the present invention, according to any one of the first to third aspects, the one end side of the rotating member is formed with a huge portion in the rotational radius direction, and the bearing cavity of the stationary member is formed. Has an enlarged portion in the radial direction of rotation that accommodates the enormous portion of the rotating member, and an axial surface of the enormous portion and an axial surface of the enlarged portion of the stationary member that opposes this with a minute gap It has the thrust dynamic pressure bearing part which uses as a bearing surface.

  According to claim 5 of the present invention, according to claim 4, a dynamic pressure groove is provided on an axial surface of the disk-like member, and the shaft is opposed to the axial member via a minute gap. It has a thrust dynamic pressure bearing part which uses the axial direction surface of the enormous part of the body as a bearing surface.

  According to a sixth aspect of the present invention, according to the fifth aspect, the concave portion is formed simultaneously with the formation of the dynamic pressure groove on the axial surface of the disk-shaped member.

  According to claim 7 of the present invention, according to any one of claims 1 to 6, the rotating member is inserted, the disk-like member is fixed to the stationary member without any gap, and a unit is manufactured. And a step of applying an adhesive to the entire circumference of the contact portion between the peripheral wall surface of the stationary member and the outer peripheral surface of the disk-shaped member, and a step of heating the unit. .

  According to an eighth aspect of the present invention, according to the seventh aspect, in the fixing step, a plastic working is used in which the stationary member is plastically deformed and fixed to the disk-shaped member.

  According to claim 9 of the present invention, according to claim 7, press-fitting is used in the fixing step.

  According to a tenth aspect of the present invention, according to any one of the first to ninth aspects, a thermosetting adhesive is used as the adhesive.

  According to an eleventh aspect of the present invention, the spindle motor is equipped with the bearing device according to any one of the first to tenth aspects.

  According to a twelfth aspect of the present invention, the recording disk drive device is equipped with the spindle motor according to the eleventh aspect.

  According to claim 1 of the present invention, the concave portion is provided on at least one of the contact surfaces of the disk-shaped member and the stationary member, so that the annular surface of the stationary member and the intersecting portion of the peripheral wall surface and the disk-shaped member The gap formed between the two and the recess communicates with each other, so that an air escape path existing in the gap can be formed and the adhesive can be smoothly permeated.

  According to claim 2 and claim 3 of the present invention, the concave portion communicates or forms a concave portion having a contact portion with a minute gap, so that the annular surface of the stationary member and the intersecting portion of the peripheral wall surface and the disk shape Since the air existing in the gap formed between the members can escape to the recesses, the adhesive can be smoothly permeated.

  According to claim 4 and claim 5 of the present invention, an enormous portion is formed at one end of the rotating member, and a thrust bearing portion is formed between the enormous portion and the stationary member and the disk-shaped member. The rotating member can be stably supported in the axial direction.

  According to the sixth aspect of the present invention, the step of forming the concave portion can be omitted by forming the concave portion simultaneously with the dynamic pressure groove formed in the disk-shaped member.

  According to the seventh aspect of the present invention, the adhesive state between the stationary member and the disk-shaped member can be stably filled by filling the adhesive after the fixing process between the stationary member and the disk-shaped member. . Moreover, since it can apply | coat to a fixing | fixed part, the contamination generate | occur | produced by this fixing process can be prevented.

  According to the eighth and ninth aspects of the present invention, the stationary member and the disk-shaped member can be more firmly fixed by using plastic working or press fitting as the fixing method.

  According to the tenth aspect of the present invention, by using a thermosetting adhesive as the adhesive, the adhesive permeates the contact surface between the stationary member and the disk-shaped member, and at the contact surface. The adhesive can be surely cured.

  According to the eleventh and twelfth aspects of the present invention, by mounting the bearing device according to any one of the first to tenth aspects, a more reliable spindle motor and the spindle motor are mounted. A recording disk drive device can be provided.

  An embodiment of a recording disk drive device 1 according to the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of the recording disk drive device 1.

  The recording disk drive device 1 is composed of a rectangular housing 2, and the housing 2 forms a clean space in which dust, dust, etc. are extremely small, and a disk for recording information in the interior. A spindle motor 4 on which a hard disk 3 is mounted is disposed.

  A head moving mechanism 5 for reading / writing information from / to the hard disk 3 is disposed inside the housing 2. The head moving mechanism 5 includes a magnetic head 5 a for reading / writing information on the hard disk 3, and the magnetic head 5 a The supporting arm 5b and the magnetic head 5a and the arm 5b are configured by an actuator unit 5c that moves the arm 5b to a required position on the hard disk 3.

  By applying the spindle motor of the present invention as the spindle motor 4 of the recording disk drive device 1 as described above, the recording disk drive device 1 can be reduced in size and thickness while ensuring a sufficient function, and also reliable. In addition, a highly durable recording disk drive device can be provided.

  Next, an overall configuration of an embodiment of the spindle motor 4 according to the present invention will be described with reference to FIG. FIG. 2 is an axial sectional view of the spindle motor 4.

  The sleeve 10 has a hollow cylindrical shape, and radial bearing portions 12 and 13 are formed on the inner peripheral surface of the cylindrical portion 11 on the upper and lower sides in the axial direction, respectively. An inner lower end surface 14 and an outer lower end surface 15 that is axially lower than the inner lower end surface 14 are formed at the lower portion of the sleeve 10. A housing 20 is fixed to the outer peripheral surface of the cylindrical portion 11 of the sleeve 10. The housing 20 is equivalent to the housing 2 of the recording disk device 1. A thrust plate 30 is fixed to the outer lower end surface 15 of the sleeve 10 so as to cover the sleeve 10.

  A cylindrical shaft 40 is inserted into the inner peripheral surface of the sleeve 10 so as to face the radial bearing surfaces 12 and 13 of the sleeve 10 in a radial direction with a small gap therebetween, and is rotatably supported. A hub 50 having a substantially bottomed cylindrical shape is fixed to the upper portion 41 of the shaft 40. Further, an enlarged portion 42 whose outer diameter is enlarged in the radial direction is formed at the lower portion of the shaft 40. The upper surface portion 42a of the enlarged portion 42 is opposed to the inner lower end surface 14 of the sleeve 10 in the axial direction with a minute gap. The lower surface portion 42b of the enlarged portion 42 faces the thrust plate 30 in the axial direction with a minute gap. Each of them forms an axial bearing surface and rotatably supports the shaft 40. These sleeve 10, thrust plate 30, and shaft 40 form a bearing device. The lubricating fluid is filled so as to fill the gaps between the radial bearing surfaces 12 and 13 of the sleeve 10 and the thrust bearing surfaces 42a and 42b without any gaps. A gas-liquid interface H is formed on the upper side in the axial direction from the radial bearing surface 12.

  The hub 50 fixed to the upper portion of the shaft 40 has a through hole 51 for fixing the shaft 40 at the center, a cylindrical portion 52, and a bottom surface portion 53 for connecting these, and the bottom surface portion 53 is disposed on the upper side in the axial direction. Is done. The cylindrical portion 52 faces the outer peripheral surface of the sleeve 10 with a minute gap. A rotor magnet 60 is fixed to the inner peripheral surface of the cylindrical portion 52. The rotor magnet 60 faces the stator 70 fixed to the outer peripheral surface of the cylindrical portion 21 of the housing 20 in the radial direction with a small gap.

  Next, fixing of the sleeve 10 and the thrust plate 30 of the bearing device of the spindle motor 4 according to the present invention will be described with reference to FIGS. 3 to 5 are enlarged views of a portion G in FIG. 2, FIG. 3 is a view immediately after the adhesive application, FIG. 4 is a view in which the adhesive penetrates into the gap 80, and FIG. The figure which penetrate | infiltrated the whole contact surface of the outer side lower end surface 15 of 10 and the thrust plate 30 is shown. The dotted line in the thrust plate 30 in FIGS. 3 to 5 indicates a recess. And the dotted line arrow of FIG. 3 shows the moving direction of the air which exists in a clearance gap.

  Referring to FIG. 3, a peripheral wall 16 that protrudes downward in the axial direction is provided on the outer side of the outer lower end surface 15 provided on the lower side in the axial direction of the sleeve 10. At the intersection between the peripheral wall 16 and the outer lower end surface 15, a concave portion 17 is provided as an adhesive reservoir. The peripheral wall 16 is also provided with a recess 16a that becomes a part of the adhesive reservoir.

  Further, chamfered portions 31 and 32 are formed at intersections between the outer peripheral surface of the thrust plate 30 and the upper and lower surfaces, respectively. By fixing the thrust plate 30 to the sleeve 10, a gap 80 is formed so that the concave portion 18 and the chamfered portion 31 of the sleeve 10 face each other. The concave portion 16a of the sleeve 10 and the chamfered portion 32 of the thrust plate 30 are combined to form an adhesive reservoir 90. The adhesive reservoir 90 is filled with a thermosetting adhesive (hereinafter referred to as an adhesive).

  Referring to FIG. 4, the adhesive attempts to fill the gap 80 by penetrating the joint between the peripheral wall 16 of the sleeve 10 and the outer peripheral surface of the thrust plate 30. At that time, the air existing in the gap 80 can escape to the outside through the recess 34. As a result, the gap 80 is filled with the adhesive.

  Referring to FIG. 5, the adhesive filled in gap 80 penetrates into the contact surface (hereinafter simply referred to as the contact surface) between outer lower end surface 15 of sleeve 10 and thrust plate 30 by surface tension. However, since the distance at the contact surface into which the adhesive permeates is very small, the surface tension is strong, so that a so-called bridge is formed in which the adhesive is filled so as to fill the axial direction of the distance. Through this bridge, the adhesive penetrates to a position where the surface tension of the gap 80 and the surface tension on the inner diameter side of the contact surface are balanced. Thereby, an interface is formed on the inner diameter side and the outer diameter side of the contact surface, and air remains in the gap 80. Even if the amount of adhesive filled in the adhesive reservoir 90 varies to some extent due to the above action, the adhesive seal on the contact surface is stably formed by the adjustment action due to the surface tension of the gap 80. This is advantageous in terms of workability for fixing the sleeve 10 and the thrust plate 30. That is, since the tolerance of variation in the amount of adhesive applied to the adhesive reservoir 90 can be increased, the amount of adhesive can be easily adjusted, and the degree of application of the adhesive can be easily confirmed visually from the outside. Therefore, since the contact surface is filled with an adhesive to form an interface and the contact surface is filled, the lubricating fluid can be prevented from entering the contact surface. Therefore, if the lubricating fluid enters the contact surface, the position of the gas-liquid interface H is lowered by the amount of the intrusion, which affects the life of the motor. Since the intrusion into the contact surface is prevented, the position of the gas-liquid interface H can be prevented from being lowered due to the intrusion of the lubricating fluid into the contact surface, and a long-life bearing device can be realized. In addition, since the air existing in the gap 80 can be prevented from entering the inside of the bearing, a highly reliable bearing device that does not affect the bearing portion can be provided.

  Next, portions of the thrust plate 30 that characterize the present invention will be described with reference to FIG.

  A dynamic pressure groove 33 is formed on the upper surface of the thrust plate 30 at a portion facing the enlarged portion 42 of the shaft 40 in the axial direction. Further, a concave portion 34 having a radial length equal to or greater than the radial length of the outer lower end surface 15 is formed in a portion that contacts the outer lower end surface 15 of the sleeve 10. The recess 34 may be formed simultaneously with the formation of the dynamic pressure groove 33. By forming the recess 34 simultaneously with the dynamic pressure groove 33, the step of forming the recess 34 independently can be omitted, and the processing cost can be reduced. The recess 34 formed in the thrust plate 30 can communicate the gap 80 with the inner lower end surface 14 of the sleeve 10 and the inner peripheral surface of the cylindrical portion 11 with reference to FIGS. 3 to 5. As a result, even if the adhesive enters the gap 80 portion, the air existing in the gap 80 can move to the outside of the gap 80 by passing through the recess 34. Thereby, the adhesive can be smoothly filled into the gap 80.

  Next, another embodiment of the recess 34 will be described with reference to FIGS. 7 and 8 are enlarged views of a portion F in FIG.

  Referring first to FIG. 7, in FIGS. 3 to 5, the recess 34 communicates the gap 80 with the inner lower end surface 14 of the sleeve 10 and the inner peripheral surface of the cylindrical portion 11. Some are not communicating. If this is part, air can permeate through the contact surface 35 a between the inner lower end surface 14 of the sleeve 10 and the upper surface of the thrust plate 30. Therefore, the same effect as described above can be obtained.

  Further, in FIG. 8, the concave portion 34b is continuously formed in the radial direction through a minute gap, and the minute gap portion serves as a contact surface 35b. This is because the contact surface 35b is a minute gap, so that air can pass through the contact surface. Therefore, the same effect as described above can be obtained. Similarly, even in the case of a surface roughness of a processing-less extent, when the surface roughness of at least one of the inner lower end surface 14 of the sleeve 10 and the corresponding portion of the upper surface of the thrust plate 30 is large, the contact A concave portion 34b as shown in FIG. 8 is formed on the surface.

  Next, the process for producing the bearing device will be described with reference to FIG.

  From the lower side in the axial direction of the sleeve 10, the shaft 40 is inserted so that the enlarged portion 42 of the shaft 40 contacts the inner lower end surface 14 of the sleeve 10. Then, the thrust plate 30 is fixed so as to contact the outer lower end surface 15 of the sleeve 10 and the peripheral wall 16. At this time, the peripheral wall 16 of the sleeve 10 has a protruding portion 16b that protrudes axially below the outer peripheral surface of the thrust plate 30 (see FIGS. 3 to 5). Then, the sleeve 10 and the thrust plate 30 are fixed by plastic deformation (caulking or press fitting) of the protruding portion 16b (step S1).

  Next, an adhesive is filled in the adhesive reservoir 90 formed by the sleeve 10 and the thrust plate 30 (the caulking portion when the fixing process is caulking, and the press-fitting portion when the fixing process is press fitting). Here, by providing the concave portion 34 at the contact portion between the outer lower end surface 15 of the sleeve 10 and the thrust plate 30, the air in the gap 70 can move to the inner peripheral surface side of the sleeve 10 due to the penetration of the adhesive. (Step S2). Here, if the caulking part and the press-fitting part are filled with the adhesive, the caulking part breaks during the caulking work, and if the caulking teeth are spilled into the caulking part, and the press-fitting work is performed. In addition, it is possible to seal the contamination generated at the joint portion, such as when the press-fitted portion is gnawed due to an uneven load due to a slight deviation.

  Next, in order to cure the filled adhesive, the bearing device is heated at about 90 ° C. for about 1 hour (step S3). The adhesive part of the present invention is always in contact with air in the part in contact with the gap 80, and there is almost no gap in the infiltrating part, and the adhesive penetrates into the invisible part from the outside. A thermosetting adhesive is most suitable for curing the agent.

  Lubricating fluid is filled into the bearing (step S4). Filling the contact surface between the outer lower end surface 15 of the sleeve 10 and the thrust plate 30 with an adhesive, and filling the bearing with the lubricating fluid after curing, prevents the lubricating fluid from entering the contact surface and the gap 70. Therefore, it is possible to prevent the air existing in the gap 70 from being replaced with the lubricating fluid, and the air does not enter the bearing.

  In the foregoing, the recording disk drive device including the bearing portion, the dynamic pressure bearing device, and the spindle motor of the present invention has been described. However, the present invention is not limited to such an embodiment, and various modifications can be made without departing from the present invention. The deformation | transformation thru | or correction | amendment are possible.

  For example, in the spindle motor 4, the sleeve 10 is formed by one member, but the sleeve 10 may be formed by two different members 10a and 10b as shown in FIG. The spindle motor 4 is also formed of a single member with respect to the expansion portion 42 located on the lower side in the axial direction of the shaft 40. However, the present invention is not limited to this and includes the expansion portion 42. Therefore, another member such as a disk-shaped cap 40a having a concave portion at the lower end portion of the shaft 40 as shown in FIG.

  Further, for example, the recess 34 is formed on the contact surface between the outer lower end surface 15 of the sleeve 10 and the thrust plate 30, and is only required to communicate with the gap 80 to secure an air escape place. May be formed not only on the thrust plate 30 but also on the outer lower end face 15 side of the sleeve 10. Moreover, the recessed part 34 should just be formed in at least any one of the sleeve 10 and the thrust plate 30. FIG. In the embodiment of the present invention, the number of the concave portions 34 is one. However, the present invention is not limited to this, and a plurality of the concave portions 34 can obtain the same effect. Moreover, in the case of the recessed part 34b continuing through a micro gap | interval like FIG. 8, you may form the recessed part 34b in a perimeter.

It is sectional drawing which shows one form of the recording disc apparatus based on this invention. It is an axial direction sectional view showing one form of a spindle motor concerning the present invention. It is the figure which filled the adhesive agent of the junction part of the sleeve and thrust plate of the bearing apparatus which concerns on this invention (It is the G section enlarged view of FIG. 2). It is the figure which the adhesive agent of the junction part of the sleeve and thrust plate of the bearing apparatus which concerns on this invention osmose | permeated the clearance gap. It is the figure which the adhesive agent of the junction part of the sleeve and thrust plate of the bearing apparatus which concerns on this invention osmose | permeated the contact surface. It is a figure which shows one form of the thrust plate which concerns on this invention. It is the figure which filled the adhesive agent of the junction part of the sleeve which showed the other Example of the recessed part which concerns on this invention, and a thrust plate (the G section enlarged view of FIG. 2). It is the figure which filled the adhesive agent of the junction part of the sleeve which showed the other Example of the recessed part which concerns on this invention, and a thrust plate. It is a figure which shows the preparation process of the bearing apparatus which concerns on this invention. It is sectional drawing which shows the other Example of the bearing apparatus which concerns on this invention. It is sectional drawing which shows the bearing apparatus which concerns on a prior art example. It is a figure which shows the junction part of the sleeve and thrust plate of the bearing apparatus which concerns on a prior art example (it is an E section enlarged view of FIG. 11).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording disk apparatus 4 Spindle motor 10 Sleeve 12, 13 Radial bearing surface 14 Inner lower end surface 15 Outer lower end surface 16 Peripheral wall 16a Recess 16b Protrusion 17 Recess 20 Housing 30 Thrust plate 31, 32 Chamfer 33 Dynamic pressure groove 34, 34a , 34b Recess 35 Contact surface 40 Shaft 42 Enlarged part 42a, 42b Thrust bearing surface 50 Hub 60 Rotor magnet 70 Stator 80 Gap 90 Adhesive reservoir

Claims (12)

A rotating member;
A stationary member;
A bearing cavity formed in the stationary member and in which the rotating member is rotatably inserted;
An annular surface formed by bending the bearing cavity radially outward at one end of the stationary member;
A peripheral wall surface that is formed to rise in one end direction at the outer edge of the annular surface and surrounds the annular surface from the outside in the radial direction;
A disk-shaped member that is disposed on one end side of the stationary member and is in contact with the annular surface and the peripheral wall surface to close the bearing cavity;
A minute gap formed on the outer peripheral surface of the rotating member and the inner peripheral surface of the bearing cavity;
A lubricating fluid that fills the minute gap;
A hydrodynamic bearing portion composed of an outer peripheral surface of the rotating member, an inner peripheral surface of the bearing cavity, and a lubricating fluid;
An adhesive interposed between the peripheral wall surface and the disk-shaped member, and sealing at least between the peripheral wall surface and the outer peripheral surface of the disk-shaped member;
In a hydrodynamic bearing device comprising:
A hydrodynamic bearing device having at least one recess formed in at least one of the contact surfaces of the annular surface of the stationary member and the disk-shaped member and extending in the radial direction.   The hydrodynamic bearing device according to claim 1, wherein the recess communicates with the peripheral wall surface and the bearing cavity.   The hydrodynamic bearing device according to claim 1, wherein the concave portion is continuously formed with a minute gap in a radial direction.   One end side of the rotating member is formed with an enormous portion in the rotating radius direction, and the bearing cavity of the stationary member has an enlarged portion in the rotating radius direction that accommodates the enlarging portion of the rotating member, 2. A thrust dynamic pressure bearing portion having a bearing surface which is an axial surface of the portion and an axial surface of the enlarged portion of the stationary member facing the surface of the stationary member with a minute gap therebetween. The hydrodynamic bearing device described in 1.   A dynamic pressure groove is provided on the axial surface of the disk-shaped member, and a thrust having the bearing surface as the axial surface of the enormous portion of the shaft body facing the axial groove with a minute gap therebetween. The hydrodynamic bearing device according to claim 4, further comprising a hydrodynamic bearing portion.   The hydrodynamic bearing device according to claim 5, wherein the concave portion is formed at the same time as a hydrodynamic groove is formed on an axial surface of the disk-shaped member. The hydrodynamic bearing device according to any one of claims 1 to 6,
Inserting the rotating member, fixing the disc-like member to the stationary member without gaps, and producing a unit;
Applying an adhesive to the entire circumference of the contact portion between the peripheral wall surface of the stationary member and the outer peripheral surface of the disk-shaped member;
Heating the unit;
It is characterized by producing by.   The hydrodynamic bearing device according to claim 7, wherein the fixing step uses plastic processing in which a stationary member is plastically deformed and fixed to a disk-shaped member.   The hydrodynamic bearing device according to claim 7, wherein press-fitting is used in the fixing step.   The hydrodynamic bearing device according to any one of claims 1 to 9, wherein a thermosetting adhesive is used as the adhesive.   A spindle motor comprising the hydrodynamic bearing device according to claim 1. 12. A recording disk drive apparatus comprising the spindle motor according to claim 11.

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