JP3158014B2 - Hydrodynamic bearing device and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrodynamic bearing device for rotatably bearing a rotary shaft such as a main shaft of a machine tool through a pressurized fluid, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, hydrodynamic bearing devices for supporting a rotating shaft by the pressure of a fluid include a hydrostatic bearing device and a hydrodynamic bearing device. First, the case of the hydrostatic bearing device will be described.

As shown in FIG. 11, a hydrostatic bearing device 10 includes a cylindrical bearing 12 and a rotating shaft 14 inserted into the bearing 12. Rectangular static pressure pockets 16a to 16d are defined on the inner wall of the bearing 12, and lands 18a to 18d are formed between the respective static pressure pockets 16a to 16d (see FIG. 12). The static pressure pockets 16a-
The edge forming the boundary between the land 16d and the lands 18a to 18d is formed parallel to the axial direction of the rotating shaft 14. At approximately the center of the static pressure pockets 16a to 16d, fluid supply passages 20a to 20d to which a pressure fluid is supplied are defined, and the supply passages 20a to 20d communicate with a pressure fluid supply source (not shown).

In the above configuration, when a pressure fluid supply source (not shown) is energized, the pressure fluid is supplied from the fluid supply passages 20a to 20d to the static pressure pocket 16a at a constant pressure.
16d, and the pressure of the fluid is applied to the outer periphery of the rotating shaft 14, and the rotating shaft 14 is levitated and supported by the fluid pressure.

[0005] Such a hydrostatic bearing device 1 according to the prior art.
When manufacturing the bearing 12, first, the bearing 12 is made of a material such as metal.
Is formed in a cylindrical shape, and the bearing 12 is mounted on the index table 22 (see FIG. 13). Next, the milling machine 28 on which the end mill 26 is mounted is urged through the angle head 24, and the milling machine 28 and the index table 22 are operated to operate the bearing 12 and the end mill 26.
And the inner wall of the bearing 12 is cut to form the static pressure pockets 16a to 16d. In this case, milling machine 2
8 and the operation of the index table 22 are controlled in advance by a program stored in a controller (not shown) connected to the milling machine 28 and the index table 22, and automatically move the bearing 12 and the end mill 26.

The angle head 24 and the end mill 2
6 and a slot cutter (not shown)
There is also a manufacturing method for cutting the static pressure pockets 16a to 16d by attaching the static pressure pockets 16 to the static pressure pocket 16a.

On the other hand, in the case of a dynamic pressure bearing device, the dynamic pressure generating groove is defined on either the bearing or the rotating shaft, but a spiral dynamic pressure generating groove is defined on the inner wall of the bearing. Therefore, usually, a spiral dynamic pressure generating groove is defined on the outer wall of the rotating shaft. That is, as shown in FIG. 14, a plurality of dynamic pressures inclined in the rotational direction (arrow A) of the rotary shaft 32 from both the predetermined position on the outer wall of the rotary shaft 32 of the dynamic pressure bearing device 30 toward the both sides in the axial direction. A groove 34 is defined. This rotating shaft 3
When 2 is inserted into the cylindrical bearing 36, the dynamic pressure generating groove 34 faces the inner wall of the cylindrical bearing 36.

In the above structure, when the rotating shaft 32 rotates, a fluid such as air is introduced from the outer end of the dynamic pressure generating groove 34 to the center of the bearing 36 along the dynamic pressure generating groove 34. , Substantially stays inside the dynamic pressure generating groove 34. The fluid pressure in the dynamic pressure generating groove 34 gradually increases, and the rotary shaft 32 is floated and supported by this pressure.

The dynamic pressure generating groove 34 is formed by cutting a rotary shaft 32 formed of a material such as metal into a cylindrical shape by a milling machine or the like.

[0010]

However, in the above prior art, in the case of the hydrostatic bearing device 10, it is necessary to accurately center the index table 22 and the bearing 12, but this process cannot be automated. Requires skill. In addition, since the cutting is performed inside the bearing 12, the cutting tool such as the end mill 26 must be small, and if the cutting is performed using this type of end mill 26 or the like, the processing time becomes long. Further, it is necessary to move the index table 22 and the milling machine 28 in a complicated manner, and a large number of man-hours are required for creating a control program. Furthermore, in order to improve the performance such as the rotational accuracy of the hydrostatic bearing device 10, a hydrostatic pocket having a complicated shape may be required. When the hydrostatic pocket having the complicated shape is formed, the milling machine 28 is required. Has become more complicated, and it has become extremely difficult to create a program, or a program cannot be substantially created. Furthermore, when manufacturing bearings 12 having different lengths in the axial direction, the bearings 12 to be manufactured are manufactured.
, A program for controlling the operations of the index table 22 and the milling machine 28 must be created in accordance with the length of the index table 22 and the number of steps increases.

Also, in the case of the dynamic pressure bearing device 30, the index table and the milling machine must be moved complicatedly because of the shape of the dynamic pressure generating groove 34 as described above. It will be extremely large. Furthermore, the dynamic pressure rigidity of the dynamic pressure bearing device 30;
In some cases, a dynamic pressure generating groove with a more complicated shape is required to improve the performance such as load capacity, but with such a dynamic pressure generating groove, the operation of the milling machine becomes more complicated, and the program creation becomes difficult. Various difficulties are revealed, such as difficulty or difficulty in creating a program.

SUMMARY OF THE INVENTION The present invention has been made to overcome the above-mentioned various inconveniences, and has a short working time, can easily form a static pressure pocket or a dynamic pressure generating groove having a complicated shape, and has a small diameter. It is an object of the present invention to provide a hydrodynamic bearing device capable of easily producing a bearing having a small size and a bearing having a different length, and a method for producing the same.

[0013]

In order to achieve the above object, the present invention comprises a bearing through which a rotating shaft is inserted, and a static pressure pocket defined on the inner wall of the bearing. in the fluid dynamic bearing device for rotatably supporting the rotary shaft by the pressure of the fluid supplied into the pocket, it is nipped with the first plate of at least two annular, by the at least two first plate, and a plurality the inner peripheral surface with single laminated, one of the second plate annular from the lamination surface having a recess which penetrates to the other stacking surface, wherein the plurality stacked second of said respective plate member The recesses are defined as static pressure pockets by communicating with each other.

The present invention also relates to a method of manufacturing a hydrodynamic bearing device which is formed by laminating plate members formed in a predetermined shape and has a hydrostatic pocket defined on an inner wall thereof. A first step of preparing at least two sheets, and
A second step of preparing a plurality of second plate annular having a recess penetrating the laminated surface of the square to the other stacking surface, the second having a plurality of stacked by at least two first plate by sandwiching the plate, pressing a third step of defining the static pressure pocket the respective recesses in communication with each other, the first plate and the second plate member that is the stacked axially and fixed And a fourth step.

Further, the present invention includes a bearing through which a rotary shaft is inserted, and a dynamic pressure generating groove defined on an inner wall of the bearing.
In the fluid bearing apparatus for freely supporting rotation of said rotary shaft by the fluid pressure that occurs by the rotation shaft fluid rotates is introduced into the dynamic pressure generating groove on the inner peripheral surface while being stacked several sheets double, Penetration from one laminated surface to the other
A second plate member of annular having a recess which, characterized in that it is defined as the dynamic pressure generating grooves by the plurality stacked second plate of each said recess to communicate with each other.

Still further, the present invention relates to a method for manufacturing a hydrodynamic bearing device, which is constituted by laminating plate members formed in a predetermined shape, and has a dynamic pressure generating groove formed in an inner wall thereof, wherein the first ring-shaped hydrodynamic bearing device comprises: A first step of preparing at least one plate member, and a second step of preparing a plurality of annular second plate members having a recess penetrating from the one laminated surface to the other laminated surface on the inner peripheral surface, by clamping the first plate member laminated on at least one by the plurality of second plate, a third step of defining the dynamic pressure generating grooves said respective recesses in communication with each other, the stack pressing a first plate and a second plate member which is axially and a fourth step of fixing, comprising: a.

[0017]

According to the present invention, in the case of a hydrostatic bearing device, pressurized fluid is introduced into the hydrostatic pocket defined by the laminated second plate. The rotating shaft is evenly levitated and supported by the pressure fluid. This bearing is formed by laminating and fixing a first plate material and a second plate material, and a static pressure pocket is defined by a recess of the second laminated plate material. For this reason, complicated processing by a conventional milling machine is not required. In addition, since the recesses are laminated while being deviated in the circumferential direction, a static pressure pocket having a complicated shape can be defined by a simple process.

In the case of the dynamic pressure bearing device, fluid is introduced into the mountain-shaped dynamic pressure generating groove defined by the laminated second plate material from the end side thereof, and substantially enters the dynamic pressure generating groove. Stay. As a result, the fluid pressure in the dynamic pressure generating groove gradually increases, and the rotating shaft is floated and supported by the pressure fluid. In this bearing, the recesses of the second plate material are stacked so as to be deviated in the circumferential direction so that the recesses of the second plate material are mountain-shaped with respect to the rotation direction of the rotating shaft. The groove can be easily defined on the inner wall side of the bearing.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a hydrodynamic bearing device according to the present invention will be described below in detail with reference to the accompanying drawings.

First, a hydrostatic bearing device will be described as a first embodiment. FIG. 1 is a partially sectional perspective view of a hydrostatic bearing device according to a first embodiment of the present invention, and FIG. 2 is a plan view of a steel plate as a first plate material constituting the hydrostatic bearing device shown in FIG. 3, FIG. 3 is a plan view of a steel plate as a second plate member constituting the hydrostatic bearing device shown in FIG. 1, FIG. 4 is a perspective view showing the configuration of the hydrostatic bearing device shown in FIG. 1, and FIG. FIG. 6 is a sectional view of the hydrostatic bearing device shown in FIG. 1, and FIG. 6 is a developed view of the hydrostatic bearing device shown in FIG.

In FIG. 1, reference numeral 40 denotes a hydrostatic bearing device according to the first embodiment. This hydrostatic bearing device 40
In the manufacture of the first, first, a circular hole 42 is defined by press working, wire cutting, laser cutting, or the like.
A predetermined number of steel plates 44 are formed (see FIG. 2). On the other hand, a hole 46 having the same diameter as the first steel plate 44 is defined, and recesses 48 a to 48 d are further defined around the hole 46.
A predetermined number of steel plates 50 are formed (see FIG. 3).

A predetermined number of the second steel plates 50 are stacked, and a predetermined number of the second steel plates 50 are stacked.
And laminated (see FIG. 4). As a result, the recesses 48a to 48d communicate with each other and
a-52d, each static pressure pocket 52a
One of the first edges 54a to 54d and the other second edges 56a to 56d in the circumferential direction are formed on the first to the second edges (see FIG. 5). At this time, each recess 48 of the second steel plate 50 is formed.
a to 48d are laminated so as to be deviated from each other by a predetermined angle in the circumferential direction, and one of the first corners 58a to 58d of the first edges 54a to 54d is connected to the other second corners 60a to 60d.
In the same manner, one third corner 62a-62d of each of the second edges 56a-56d is displaced from the other fourth corners 64a-64d by a length B in the circumferential direction with respect to d. The static pressure pockets 52a to 52d are defined in a shape twisted along the circumferential direction (see FIG. 6).

The distance between the first corner 58a and the third corner 62b adjacent to the first corner 58a is formed to be smaller than the length B. 58b and 3rd
A corner 62c, a first corner 58c and a third corner 62d,
The distance between the first corner 58d and the third corner 62a is smaller than the length B. For this reason, the first edge portions 54a-5
The vicinity of the first corners 58a to 58d of the 4d is a second edge 56.
The length b overlaps the vicinity of the fourth corners 64b to 64a of b to 56a by the length C in the axial direction.

The first steel plate 44 and the second steel plate
The steel plate 50 is pressed in the thickness direction and fixed by bolting or bonding to form the bearing 66. As a method of fixing by bonding, the laminated first steel plate 44 and second steel plate 50 are vacuum-impregnated with a synthetic resin, or the first steel plate 44 and the second steel plate 50 are heated and vacuum-impregnated with a low-temperature molten metal. And the first before lamination
A method in which an adhesive is applied to the steel plate 44 and the second steel plate 50, and the layers are pressed and fixed after lamination may be used.

Fluid supply passages 68a to 68d through which a pressurized fluid is introduced are defined substantially at the center of the static pressure pockets 52a to 52d thus configured. The fluid supply passages 68a to 68d are defined by using a drill or the like from the outer wall of the bearing 66. The fluid supply passages 68a to 68
d is communicated with a pressure fluid supply source (not shown).

Next, the inner periphery of the bearing 66 is polished and
Burrs, adhesives and the like of the steel plate 44 and the second steel plate 50 are scraped off. Then, the rotating shaft 70 is inserted into the bearing 66.

Next, the operation of the hydrostatic bearing device 40 according to the present embodiment will be described.

When a pressure fluid supply source (not shown) is energized, a fluid such as oil is introduced into the static pressure pockets 52a to 52d at a constant pressure from the fluid supply passages 68a to 68d. Is applied, and the rotating shaft 7
Numeral 0 is floated and supported by this fluid pressure. Therefore, the rotating shaft 70 can rotate inside the bearing 66 with extremely small friction.

When the rotating shaft 70 has irregularities or roundness distortion along the axial direction, for example, if the minute convex portion 72 extends in the axial direction of the rotating shaft 70, the convex portion 72 When facing the static pressure pocket 52a, the fluid pressure applied to the convex portion 72 tends to cause the rotating shaft 70 to be deviated in the opposite direction to the convex portion 72 (see FIG. 5). In this case, the rotating shaft 7
When 0 rotates, the convex portion 72 engages the second corner portion 60a of the static pressure pocket 52a (see FIG. 6), and when further rotated, the convex portion 72 relatively moves along the first edge portion 54a,
The area of the convex portion 72 facing the static pressure pocket 52a gradually decreases. For this reason, the fluid pressure applied to the convex portion 72 gradually decreases, and the rotating shaft 70 is displaced toward the center of the axis.

The convex portion 72 is formed at the first corner portion 58a.
Immediately before reaching the second edge 56b.
Therefore, fluid pressure is applied to the convex portion 72 from both the static pressure pocket 52a and the static pressure pocket 52b.

When the rotating shaft 70 further rotates, the area of the convex portion 72 facing the static pressure pocket 52b increases, and the fluid pressure applied to the convex portion 72 gradually increases. And deviates in the opposite direction. Then, the convex portion 72 reaches a position facing the static pressure pocket 52b via the third corner portion 62b.

As described above, the pressure applied to the projection 72 is the first
Since the rotation gradually changes at the edges 54a to 54d and the second edges 56a to 56d, the rotation of the rotary shaft 70 from the axial center does not occur rapidly, and the rotary shaft 70 rotates without generating runout. Also,
The convex portion 72 is always provided with any of the static pressure pockets 52a to 52d.
, The amount of deflection of the rotating shaft 70 is suppressed, and the rotation accuracy is improved.

Hydrostatic bearing devices 40 having different axial lengths
Is manufactured, the hydrostatic bearing device 40 having a desired length can be obtained by the same manufacturing method only by changing the number of stacked first steel plates 44 and second steel plates 50.

Next, a dynamic bearing device will be described as a second embodiment.

FIG. 7 is a perspective view, partly in section, of a hydrodynamic bearing device according to a second embodiment of the present invention, and FIG. 8 is a steel plate as a third plate constituting the hydrodynamic bearing device shown in FIG. FIG. 9 is a plan view of a steel plate as a fourth plate member constituting the dynamic bearing device shown in FIG. 7, and FIG. 10 is a perspective view showing the configuration of the dynamic bearing device shown in FIG. .

In FIG. 7, reference numeral 80 denotes a hydrodynamic bearing device according to the second embodiment. This dynamic pressure bearing device 80
First, as in the first embodiment, a third steel plate 84 in which a circular hole 82 is defined and a third steel plate 8
A predetermined number of fourth steel plates 90 each having a hole 86 having the same diameter as the hole 4 and having a plurality of recesses 88 formed around the hole 86 are formed (see FIGS. 8 and 9).

Next, a predetermined number of the third steel plates 84 are stacked, and a predetermined number of the fourth steel plates 84 are stacked.
It is sandwiched and laminated by a steel plate 90 (see FIG. 10). At this time, the respective recesses 88 of the fourth steel plate 90 are stacked so as to be deviated from each other by a predetermined angle in the circumferential direction, so that the recesses 88 communicate with each other and are defined as dynamic pressure generating grooves 92. . Further, the dynamic pressure generating groove 9 constituted by the fourth steel plate 90 laminated on one end side of the laminated third steel plate 84
2 and the dynamic pressure generating groove 92 composed of the fourth steel plate 90 laminated on the other end side, the directions of the deviations are opposite to each other so as to incline in the opposite direction along the axis. Laminate. As a result, the recess 88 of the fourth steel plate 90 stacked on one end and the recess 8 of the fourth steel plate 90 stacked on the other end are formed.
8, the dynamic pressure generating groove 92 is defined in a chevron. In this case, since the third steel plate 84 is sandwiched between the fourth steel plate 90 at one end and the other end, the recess 88 at the one end and the other end is blocked by the third steel plate 84, respectively. Become.

The third steel plate 84 and the fourth steel plate 84
The bearing 94 is formed by pressing the steel plate 90 in the thickness direction and fixing the steel plate 90 by bolting or bonding.

Next, the inner periphery of the bearing 94 is polished to form a third
Burrs, adhesives and the like of the steel plate 84 and the fourth steel plate 90 are scraped off. Then, the rotating shaft 96 is inserted into the bearing 94.

Next, the operation of the hydrodynamic bearing device 80 according to this embodiment will be described.

When the rotating shaft 96 rotates in the direction of arrow D,
Fluid such as air around the rotating shaft 96 is introduced from the opening 98 of the dynamic pressure generating groove 92 by friction with the rotating shaft 96 (see FIG. 7). This fluid moves along the dynamic pressure generating groove 92 to reach the end 100 of the dynamic pressure generating groove 92, and the fluid is supplied from the dynamic pressure generating groove 92, so that the fluid has a high pressure at the end 100. This pressure causes the rotating shaft 96 to float and be supported, so that the rotating shaft 96 can rotate inside the bearing 94 with extremely small friction.

Dynamic pressure bearing devices 80 having different axial lengths
Is manufactured, the dynamic pressure bearing device 80 having a desired length can be obtained by the same manufacturing method only by changing the number of stacked third steel plates 84 and fourth steel plates 90.

[0043]

According to the hydrodynamic bearing device and the method of manufacturing the same of the present invention, the following effects and advantages can be obtained.

The bearing is formed by laminating and fixing a first steel plate and a second steel plate, and a static pressure pocket and a dynamic pressure generating groove are defined by a recess of the second steel plate. For this reason, complicated machining with a cutting tool such as a milling machine is not required, and the machining time can be shortened and the manufacturing cost can be reduced. Further, since the recesses are deviated in the circumferential direction and laminated, a static pressure pocket and a dynamic pressure generation groove having a complicated shape can be defined by a simple process, and performance such as rotation accuracy is improved. . Furthermore, a bearing having a small diameter can be easily manufactured, and a bearing having a different length in the axial direction can be manufactured by simply changing the number of the first and second steel plates to be laminated.

[Brief description of the drawings]

FIG. 1 is a partially sectional perspective view of a hydrostatic bearing device according to a first embodiment of the present invention.

FIG. 2 is a plan view of a first steel plate constituting the hydrostatic bearing device shown in FIG.

FIG. 3 is a plan view of a second steel plate included in the hydrostatic bearing device shown in FIG.

4 is a perspective view showing a configuration of the hydrostatic bearing device shown in FIG.

FIG. 5 is a sectional view of the hydrostatic bearing device shown in FIG. 1;

FIG. 6 is a development view of the hydrostatic bearing device shown in FIG.

FIG. 7 is a perspective view, partly in section, of a hydrodynamic bearing device according to a second embodiment of the present invention.

FIG. 8 is a plan view of a third steel plate included in the dynamic bearing device shown in FIG. 7;

FIG. 9 is a plan view of a fourth steel plate included in the dynamic bearing device shown in FIG. 7;

FIG. 10 is a perspective view showing a configuration of the dynamic pressure bearing device shown in FIG.

FIG. 11 is a partial cross-sectional perspective view of a hydrostatic bearing device according to the related art.

FIG. 12 is a sectional view of the hydrostatic bearing device shown in FIG.

13 is a front view of a manufacturing apparatus of the hydrostatic bearing device shown in FIG.

FIG. 14 is a partial cross-sectional perspective view of a hydrodynamic bearing device according to a conventional technique.

[Explanation of symbols]

40 ... hydrostatic bearing device 44, 50, 8
4, 90 ... steel plates 48a to 48d, 88 ... recesses 52a to 52d ...
Static pressure pockets 66, 94: Bearings 70, 96: Rotating shaft 80: Dynamic pressure bearing device 92: Dynamic pressure generating groove

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsuneo Takiguchi 1-10-1 Shinsayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. (56) References JP-A-5-133419 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) F16C 32/00

Claims (10)

(57) [Claims] 1. A bearing in which a rotating shaft is inserted, and a static pressure pocket defined on an inner wall of the bearing, wherein the rotating shaft is rotatably supported by a pressure of a fluid supplied to the static pressure pocket. in the fluid bearing apparatus, the first plate of at least two annular, the sandwiched by at least two first plate, on the inner peripheral surface with and are plurally stacked, from one lamination surface
It comprises a second plate annular having a recess which penetrates to the other lamination surface, and the static pressure pocket by said plurality stacked second said <br/> recesses of the respective plate member communicate with each other A hydrodynamic bearing device characterized by being defined. 2. A hydrodynamic bearing apparatus according to claim 1, wherein the second plate member having a plurality of stacked, displaced in the recess each other circumferentially of the respective and, each of said recesses
The line connecting the ends of is inclined with respect to the axis of the second plate.
Fluid bearing apparatus characterized by being urchin laminated. 3. The hydrodynamic bearing device according to claim 2, wherein one of said static pressure pockets is arranged in one of circumferential directions.
One end of a first edge portion of the first edge portion and a circumferential direction of the first edge portion.
With at least one part that is relatively deviated at
The relative distance in the direction is a first distance, the one end and another static pressure port adjacent to the first edge.
Circumferential direction with one end of the other second edge of the ket
Wherein the first distance is greater than the second distance, where the relative distance of the second axis is the second distance . 4. A method of manufacturing a hydrodynamic bearing device comprising a plurality of plate members formed in a predetermined shape, wherein a hydrostatic pocket is defined on an inner wall, wherein at least two annular first plate members are prepared. And a second step of preparing a plurality of annular second plate members having a recess penetrating from the one laminated surface to the other laminated surface on the inner peripheral surface.
And step by the clamping the second plate having a plurality of stacked by at least two first plate, a third step of said respective recess to define a static pressure pocket communicating with each other pressing a first plate and a second plate which are the stacked axially, manufacturing method of a fluid bearing device for a fourth step of fixing, comprising: a. 5. A method of manufacturing a hydrodynamic bearing apparatus according to claim 4, wherein in the third step, the plurality of second plate member, deviated the recess each in one another circumferentially, and, Respectively
The line connecting the ends of the recess is
Method for producing a fluid bearing device according to claim Rukoto are stacked so as to be inclined Te. 6. A bearing in which a rotary shaft is inserted, and a dynamic pressure generating groove defined on an inner wall of the bearing, wherein the rotary shaft rotates to introduce a fluid into the dynamic pressure generating groove. in the fluid dynamic bearing device for rotatably supporting the rotating shaft by the fluid pressure that occurs, the inner peripheral surface while being stacked several sheets double, the other from one lamination surface
Annular second plate having a recess penetrating to one of the lamination surfaces
Comprising a timber, prior to each of the plurality stacked second plate
Fluid bearing apparatus characterized by defined as dynamic pressure generating grooves by serial recesses communicate with each other. 7. The fluid bearing apparatus of claim 6, wherein the dynamic pressure generating grooves defined by said plurality second plate which are stacked in is formed in a mountain shape with respect to the rotational direction of the rotary shaft A hydrodynamic bearing device. 8. The hydrodynamic bearing device according to claim 7, wherein an annular first plate material is less at the mountain-like top of said dynamic pressure generating groove.
The hydrodynamic bearing device is characterized in that the dynamic pressure generating groove is shut off by arranging a single hydrodynamic bearing. 9. A method of manufacturing a hydrodynamic bearing device comprising a plurality of plate members formed in a predetermined shape and having a dynamic pressure generation groove defined in an inner wall, wherein at least one annular first plate member is provided. A first step of preparing, and a second step of preparing a plurality of annular second plate members having a recess penetrating from the one laminated surface to the other laminated surface on the inner peripheral surface.
Steps and, by clamping the first plate member laminated on at least one by the plurality of second plate, the third step of the respective recess defining the dynamic pressure generating grooves communicate with each other When pressing the first plate and the second plate member that is the stacked axially, manufacturing method of a fluid bearing apparatus comprising: the fourth step, the fixed. 10. A method for producing a fluid bearing device according to claim 9, image like a mountain said third of said recess of each of the plurality of second plate, in the process with respect to the rotational direction of the rotary shaft as the hydrodynamic grooves which form, deviated from each other a plate material of said second circumferentially, and end portions of each of said recesses
So that the line connecting them is inclined with respect to the axis of the second plate.
Method for producing a fluid bearing device according to claim Rukoto the layers.