JP2001115278A - Method for forming groove for generating dynamic pressure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming grooves for generating dynamic pressure which is capable of suppressing the labor and time for processing to a lower level. SOLUTION: This method for forming the grooves for generating dynamic pressure consists in fixing a plurality of original members 10 having hollow parts penetrating in an axial direction onto a shaft 20 (a), (b), then immersing the shaft into a photoresist type solution S to be provided with corrosion resistance by exposure and drying the same to form preresist layers P on the outer peripheral surfaces of the original members 10 (c), (d), mounting cylindrical mask drums 27 formed with light opaque parts 272 in correspondence to the groove forming portions to all the outer circumferences of the original members 10 (e), making the portions exclusive of the groove forming positions among the preresist layers P corrosion resistant by irradiation with light from the outside of the mask drums 27 (f) and immersing the original members 10 into an etchant E to each the groove forming portions (h), then removing the resist layers R remaining on the surfaces of the original members 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic pressure generating groove forming method for forming a dynamic pressure generating groove in a dynamic pressure bearing, and more particularly, to reducing the labor and time required for processing. The present invention relates to a dynamic pressure generating groove forming method capable of forming a dynamic pressure generating groove at low cost.

[0002]

2. Description of the Related Art Conventionally, it is well known that a dynamic pressure is generated by a dynamic pressure generating groove as a dynamic pressure bearing for generating a dynamic pressure by rotation and supporting the rotor side to the stator side by the dynamic pressure. I have. FIG. 4 is a cross-sectional view showing a motor using a dynamic pressure bearing that generates dynamic pressure by a dynamic pressure generating groove. FIG. 5 is a perspective view showing a state in which a bearing ring in the motor of FIG. 4 is fixed to a shaft. It is. In this motor, as shown in FIG. 4, a columnar portion 131 extends from the center of the top surface of a cylindrical hub 132 having a top surface, and a bearing ring 152 is inserted through the hollow portion of the columnar portion 131. The rotor includes a fixed rotor 130 and a stator 110 having a fitting portion 110a. And the fitting portion 1
The columnar portion 131 is mounted on 10a together with the bearing ring 152. The fitting portion 110a is provided with a bearing ring 152.
The peripheral surface of the fitting portion 110a of the stator 110 is spaced from the peripheral surface and the end surface of the bearing ring 152, and the peripheral surface of the columnar portion 131. It is possible to oppose. Thereby, the rotor 130 is rotatably supported by the stator 110. The fitting portion 110a of the stator 110 is
A gap between the bearing 30 and the bearing ring 152 is filled with a fluid F such as air or oil. The rotor magnet 160 is fixed to the inner peripheral surface of the hub 132. Stator 110
A stator coil 140 is fixed to the outer peripheral surface of the rotor. A rotating magnetic field is formed by the stator coil 140, and the rotating magnetic field urges the rotor magnet 160 so that the rotor 130 rotates in a certain direction. I have.

As shown in FIG. 5, a bearing ring 152
Herringbone grooves 15 as dynamic pressure generating grooves
2a are formed, and both ends of the bearing ring 152 and the fitting portion 11 of the stator 110 opposed to these end surfaces by the herringbone groove 152a when the rotor rotates.
The fluid is drawn into the gap between the outer peripheral surface and the outer peripheral surface to generate a dynamic pressure in the thrust direction. In addition, bearing ring 1
52, two diagonal grooves 1 as grooves for generating dynamic pressure.
52b are formed, and the bearing ring 152 is formed by the two hatched grooves 152b when the rotor 130 rotates.
And the fitting portion 1 of the stator 110 facing this peripheral surface
Fluid is drawn between the inner peripheral surface 10a and a radial dynamic pressure. And rotor 1
When 30 is rotated, herringbone grooves 152a and 152a
Dynamic pressure is generated in each of the thrust direction and the radial direction by the hatched groove 152b, and the rotor 130 is supported by the stator 110 in a non-contact state. As described above, when the rotor 130 is supported on the stator 110 using the dynamic pressure bearing, there is an advantage that friction between the rotor-side member and the stator-side member is small, and good durability can be obtained.

In the production of the above-mentioned dynamic pressure bearing,
As a method of forming a dynamic pressure generating groove (a herringbone groove 152a and two diagonal grooves 152b in the motors of FIGS. 4 and 5), a conventional method involves etching a substrate. A method (etching) is employed. That is, a member for forming a dynamic pressure generating groove such as the bearing ring 152 is formed in advance, a photoresist layer is formed on the surface of each of these members, and the members other than the dynamic pressure generating groove are irradiated with laser light or the like. After the portion is hardly dissolved, the portion corresponding to the dynamic pressure generating groove is melted out with a solvent (etchant) to form the dynamic pressure generating groove. The photoresist layer is thereafter removed with a solvent.

[0005]

In the above-described conventional method for forming a groove for generating dynamic pressure, the member in which the groove of each bearing is formed (the bearing ring 152 in the dynamic pressure bearing of the motor of FIG. 3). Each one is handled separately, and a different jig is used in each step for each member. And jigs can be replaced for each member,
It takes enormous amount of time and effort to perform the processing, which may lead to an increase in cost. In particular, in the case of a bearing used for a motor of a hard disk for a personal computer, etc., each of the members for each bearing is Very small,
It takes time and effort for processing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and can reduce the time and labor required for processing, and can form a dynamic pressure generating groove at low cost. It is an object of the present invention to provide a groove forming method.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a method in which a plurality of cylindrical members having hollow portions penetrating in the axial direction are inserted into a common shaft.
A fixing alignment step, and after the aligning step, of the outer peripheral surface of the cylindrical member fixed to the shaft, in addition to a groove forming position for forming a groove for generating a dynamic pressure, corrosion resistance to an etchant. A resist layer forming step of forming a resist layer, and after the resist layer forming step, the cylindrical member is immersed in the etching solution, and an etching step of etching the groove forming portion is performed. And a resist layer removing step of removing the resist layer remaining on the shape member.

In this dynamic pressure generating groove forming method, when a cylindrical member having a hollow portion is used as a member for forming the dynamic pressure generating groove, the hollow portion of the cylindrical member is utilized.
A plurality of tubular members are fixed to a common shaft. A resist layer can be formed, etched and the resist layer can be removed while handling these tubular members collectively while being fixed to the shaft, so that handling is easy, and many cylinders can be handled with little trouble. A groove for generating dynamic pressure can be formed in the shaped member. In addition, manufacturing by a flow operation is easy. In the method of forming a groove for generating dynamic pressure according to the first aspect of the present invention, the resist layer forming step includes forming a corrosion-resistant layer over the entire outer peripheral surface while the cylindrical member is fixed to the shaft. And a removing step of removing only a portion of the corrosion-resistant layer where a groove for generating dynamic pressure is to be formed by laser irradiation or the like after the step of forming the entire corrosion-resistant layer. Further, as a resist layer forming step, a pre-corrosion-resistant layer forming step of forming a pre-corrosion-resistant layer which is made to be corrosion-resistant by exposure over the entire outer peripheral surface of the cylindrical member fixed to the shaft, and a pre-corrosion-resistant layer forming step After that, an exposure step of exposing portions of the pre-corrosion-resistant layer other than the dynamic pressure generating grooves to make it corrosion-resistant, and after the exposure step, removing the pre-corrosion-resistant layer remaining unexposed in the exposure step. And a pre-corrosion-resistant layer removing step.

In the method for forming a groove for generating dynamic pressure according to the first aspect of the invention, the resist layer forming step includes the steps of developing and fixing after light irradiation onto the entire outer peripheral surface of the cylindrical member fixed to the shaft. A pre-resist layer forming step of forming a pre-resist layer by performing a heat treatment at a predetermined temperature for a predetermined time after adhering a photoresist property solution which can be removed by Exposing a portion of a groove forming position for forming a generating groove, developing and fixing, removing the pre-resist layer at the groove forming position, and fixing a portion other than the groove forming position; After the exposure, development and fixing steps, the post-resist step of forming a resist layer by leaving the pre-resist layer remaining and fixed at a predetermined temperature for a predetermined time to make it corrosion-resistant. It can be (second invention).
As described above, by forming the pre-resist layer using a photoresist solution of a negative resist that can be removed by development and fixing after light irradiation, only the pre-resist layer at the groove forming position can be easily formed by light irradiation. Can be removed. Also, a pre-resist layer is formed on the inner peripheral surface, etc.
By exposing from the outer peripheral surface side, a resist layer can be easily formed also on the inner peripheral surface side.

In the method of forming a groove for generating dynamic pressure according to the second aspect of the present invention, the exposing, developing and fixing steps are performed in such a manner that light is applied to all the groove forming portions of the plurality of cylindrical members fixed to the shaft. A cylindrical mask drum in which a transparent portion is formed and the light transmissive portion other than the light transmissive portion is formed to be light impermeable, around the outer periphery of the plurality of cylindrical members fixed to the shaft,
A mask drum mounting step of fixing the position with respect to the cylindrical member; and, after the mask drum mounting step, irradiating light toward the cylindrical member from outside the mask drum to form the pre-resist. An exposure step of exposing a portion of the layer at the groove forming position; and, after the exposing step, removing the pre-resist layer at the portion of the groove forming position that has been exposed, and removing the pre-resist layer at a portion other than the groove forming position that has not been exposed. Developing and fixing steps for fixing the resist layer (third step)
Invention). As described above, in the dynamic pressure generating groove forming method of the present invention, by using the cylindrical mask drum extending over the entire length in the axial direction of all of the plurality of cylindrical members fixed to the shaft, With respect to the cylindrical member, the groove forming portion of the pre-resist layer can be removed by exposing it at one time.

In the second invention or the third invention,
The pre-resist layer forming step may include forming the pre-resist layer also on the inner peripheral surfaces of the plurality of cylindrical members (a fourth invention). In this way, in the pre-resist layer forming step, if the pre-resist layer is also formed on the inner peripheral surface of the tubular member, the inner resist is formed by the exposure / development / fixing step and the post resist step subsequent to the pre-resist layer forming step. A resist layer is also formed on the peripheral surface. Therefore, when the cylindrical member is immersed in the etching solution during the etching process, it is possible to reliably prevent the inner peripheral surface from being etched.

In the fourth aspect, the aligning step includes fixing the tubular member to the shaft having a passage communicating the outside of the plurality of tubular members and the hollow portion;
In the pre-resist layer forming step, the cylindrical member fixed to the shaft is immersed in the photoresist-based solution, and the solution is also adhered to the inner peripheral surface through the passage of the shaft. 5 invention).

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. The present embodiment is a method for forming a dynamic pressure generating groove when forming a dynamic pressure generating groove in the bearing ring 152 shown in FIGS. FIG. 1 is an explanatory view conceptually showing each step of a method for forming a groove for generating dynamic pressure as a first embodiment of the present invention, and FIG. 2 is a diagram showing a second step of the present invention following each step of FIG. It is explanatory drawing which shows notionally each process of the dynamic pressure generation groove | channel formation method as one Embodiment.

In the method of forming a groove for generating dynamic pressure according to this embodiment,
First, a plurality of original members 10 of the bearing ring 152 forming the dynamic pressure generating grooves are formed (original member forming process). This original member is made of a metal such as aluminum or stainless steel, and has the same shape (cylindrical shape) and size as the bearing ring 152 except that a dynamic pressure generating groove is not formed. Then, the plurality of original members 10 are fixed to the shaft 20 rotated at a predetermined rotation speed by the motor (alignment process). Shaft 2 used in this alignment process
As shown in FIG. 1 (a), a plate-like fastening portion 21 is provided at the end on the motor side, which spreads in the radial direction of rotation. The end (tip) opposite to the motor is thread 2
2 are formed. Then, the shaft 20 is inserted into the hollow portion of each of the predetermined number of the original members 10, and a fastening plate 25 having a hole is attached from the tip end side of the shaft 20. Further, the nut 24 is screwed and fastened from the outside of the clamped 25 to clamp the original member 10 between the clamp portion 21 and the clamp plate 25 (FIG. 1B). Thereby, both end surfaces of each original member 10 are joined to one of the end surface of the adjacent original member 10, the fastening portion 21, and the fastening plate 25 and are not exposed, so that the shaft 20 rotates together with the shaft 20.
Fixed against.

Next, the original member 10 fixed to the shaft 20 in the aligning process is immersed together with the shaft 20 in a photoresist solution S which is made corrosion-resistant by exposure (FIG. 1).
(C)). In the photoresist solution S, a portion irradiated with light is removed by a developing and fixing process. At this time, in the alignment process, both end surfaces of each original member 10 are in a state of being joined to any one of the end surface of the adjacent original member 10, the fastening portion 21, and the fastening plate 25. The photoresist solution S does not enter between the two. Then, after the shaft 20 is pulled up from the solution S, the shaft 20 is engaged with the motor, and the shaft 20 is rotated at a predetermined number of revolutions by the motor so that the thickness of the attached photoresist solution S becomes a predetermined amount. The photoresist solution S is removed by centrifugation until complete. Then, the shaft 20 is removed from the motor,
Heat treatment is performed at 100 ° C. for 15 to 30 minutes. Thus, a pre-resist layer P having a predetermined thickness is formed on the outer peripheral surface of the original member 10 fixed to the shaft 20 (pre-resist layer forming step) (FIG. 1D). As the photoresist solution S, the photoresist properties of a negative resist, which is conventionally used in an etching process when forming a dynamic pressure generating groove of a dynamic pressure bearing and in which a light-irradiated portion is removed by development and fixing, are used. Can be used without any particular limitation. The number of rotations and rotation time when rotating the shaft 20 by the motor are determined by the viscosity of the photoresist solution S and the thickness of the pre-resist layer P to be formed.

After forming the pre-resist layer P, the nut 24 and the fastening plate 25 are once removed, and the cylindrical mask drum 27 is mounted on the original member 10 fixed to the shaft 20, and then the fastening plate 25 is fitted again. The nut 24 is screwed (mask drum mounting process) (FIG. 1E). The length of the mask drum 27 in the axial direction extends over the entirety of the original member 10 fixed to the shaft 20. Are enclosed and fixed together with the original member 10 by the fastening portion 21 and the fastening plate 25. Further, when the mask drum 27 is mounted around the outer periphery of the original member 10, the position corresponding to the portion where the groove for generating dynamic pressure is formed on the outer peripheral surface of each original member 10 is the light transmitting light. The other portion is a light-impermeable portion 272 that does not transmit light. The mask drum 27 is made of a nickel electroformed permeable portion 271.
Can be used, or a quartz glass cylinder in which a thin film of chromium or nickel is formed on the inner surface of a quartz glass cylinder by vapor deposition or sputtering and the light transmitting portion 271 is removed using a laser or the like can be used.

Next, with the mask drum 27 mounted, the shaft 20 is erected on a rotatable table T, and the original member 10 is rotated from outside while rotating the table T.
2. Emit parallel light toward (exposure process) (FIG. 2)
(F)). At this time, when a plurality of shafts 20 are simultaneously erected on one table T, they are arranged at the same distance from the center of rotation of the table and at the same circumference as the table T. Since the emitted parallel light does not pass through the light-impermeable portion 272,
The portion of the pre-resist layer P where the groove for generating dynamic pressure is formed is kept as it is, and the light transmitting portion 271 of the mask drum 27 is transmitted. The portion where the pressure generating groove is formed is exposed. The exposure time is determined by the type (component, composition) and thickness of the pre-resist layer P, the intensity of parallel light, and the like. Subsequently, the mask drum 27 is removed, development and fixing are performed, the pre-resist layer P in the exposed portion is removed (development and fixing process), and a predetermined temperature (80 to 12).
By leaving the pre-resist layer P at a temperature of 0 ° C. for a predetermined time (30 to 60 minutes) and performing heat treatment, the remaining pre-resist layer P is made to be corrosion-resistant, and the etching solution is applied only to a groove forming position other than a groove forming position for forming a dynamic pressure generating groove. On the other hand, a corrosion-resistant resist layer R is formed (post-resist process) (FIG. 2G).

Thereafter, the original member 10 is immersed in the etching solution E together with the shaft 20 (etching step) (FIG. 1 (h)).
As a result, the inside of the part of the pre-resist layer P which has become the corrosion-resistant resist layer R is kept as it is, and the inside of the part of the pre-resist layer P which has not been made corrosion-resistant is the etching solution E. Corroded by the original member 1
At 0, a groove for generating dynamic pressure is formed. As the etchant E, an etchant conventionally used for etching the dynamic pressure generating groove in the etching process for forming the dynamic pressure generating groove of the dynamic pressure bearing can be used. For example, when the original member 10 is made of aluminum, etching can be performed at 60 to 90 ° C. using a mixed solution of phosphoric acid, acetic acid, nitric acid, and pure water as the etching solution E,
When the original member 10 is made of stainless steel, etching can be performed at normal temperature using an aqueous ferric chloride solution. Further, the dynamic pressure generating groove 15 to be formed depends on the size of the original member 10, the distance between the original member and the opposing member in the dynamic pressure bearing in which the original member 10 is used, the use, and the like. When used for a bearing of a polygon mirror motor or the like, the thickness is preferably 5 to 7, 8 μm from the surface of the original member 10. The type, concentration, temperature, and etching time of the etching solution E are appropriately selected and determined depending on the type of the resist layer R, the type of the original member, the depth of the dynamic pressure generating groove to be formed, and the like.

Then, the original member 10 is taken out of the etching solution E together with the shaft 20 and the etching solution E is washed away, and then represented by an organic solvent such as acetone or thinner.
The resist layer R on the surface of the original member 10 is dissolved and removed by dipping in a solution in which the resist layer R is soluble and the original member 10 is insoluble (resist layer removing step) (FIG. 2 (i)). Thereafter, the nut 24 screwed to the shaft 20 is removed, and the original member 10 is detached from the shaft 20. Through the above steps, a dynamic pressure generating groove 152b for generating a dynamic pressure in the radial direction is formed on the outer peripheral surface of the original member 10. After forming the dynamic pressure generating groove for generating the radial dynamic pressure in this manner, the dynamic pressure generating groove 152a for generating the thrust direction dynamic pressure is formed on the end surface of each of the original members 10 by the same method as the related art. Then, the dynamic pressure generating groove forming method according to the present embodiment ends.

As described above, the dynamic pressure generating groove forming method of the present embodiment utilizes the fact that the dynamic pressure generating groove is formed in the cylindrical member (bearing ring 152) to form the dynamic pressure generating groove. A common support shaft 20 is inserted into the hollow portion of each of the plurality of cylindrical original members 10 to be formed, and the plurality of original members 10 are separated by the fastening portions 21 and the fastening plates 25 of the support shaft 20.
It is fixed to the support shaft 20 with its outer peripheral surface exposed. The original member 10 fixed to the support shaft 20
, Immersing in a photoresist solution S, forming a pre-resist layer P, forming a resist layer R, etching, and removing the resist layer R to form a dynamic pressure generating groove on the outer peripheral surface. Form. Therefore, the work of each process can be performed easily and efficiently as compared with the case of individually handling small original members one by one as in the related art.

In the dynamic pressure generating groove forming method of the present embodiment, the length in the axial direction is the length extending over all of the original members 10 fixed to the support shaft 20, and the dynamic pressure of each of the original members 10 Using a mask drum having a light-transmitting portion corresponding to the generation groove forming portion, simultaneously exposing and removing the pre-resist layer of the dynamic pressure generation groove forming portion for all of the original members 10 fixed to the support shaft 20, In addition, the pre-resist layer other than the portion where the dynamic pressure generating groove is formed can be made resistant to corrosion, and the exposure, development, and fixing processes can be performed more easily and more efficiently than in the conventional case where individual small original members 10 are individually handled. Layer R can be formed.

Next, a second embodiment of the dynamic pressure generating groove forming method of the present invention will be described. In the present embodiment, the description of the same steps as those in the above-described first embodiment will be omitted. Further, the same members as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 3 is a side view showing the support shaft 20 used in the method for forming a dynamic pressure generating groove according to the present embodiment. As shown in FIG. 3, in the present embodiment, the support shaft 20 to which the original member 10 is fixed in the alignment process is
A number of axial grooves 20a are provided on the peripheral surface. And
The retaining portion 21 has a groove 20 a formed on the peripheral surface of the support shaft 20.
And a communication hole 21a that communicates the retaining portion 21 with the opposite side of the groove 20a. Also, on the fastening plate 25,
A passage hole 25a is formed to communicate the groove 29 on the peripheral surface of the support shaft 20 and the side opposite to the groove 20a with respect to the retaining plate 25. Then, in the pre-resist layer forming process, when the original member 10 fixed to the support shaft 20 is immersed in a solution S of a photoresist, the communication hole 21 a of the fastening portion 21 is formed.
And the support shaft 20 through the passage hole 25a of the retaining plate 25.
The solution S advances and adheres to the inner peripheral surface of the original member 10 from the groove 20a.

Then, similarly to the above-described first embodiment,
By performing a heat treatment at 80 to 100 ° C. for 15 to 30 minutes, a pre-resist layer is formed on both the outer peripheral surface and the inner peripheral surface of the original member 10. (Pre-resist layer forming process). After the pre-resist layer P is formed, a mask drum similar to that described above is mounted (mask drum mounting step), and when exposure is performed (exposure step), the inner peripheral surface is not irradiated with light.
Subsequently, when development, fixing, and heat treatment are performed, a resist layer R is formed on portions of the outer peripheral surface other than the portion where the dynamic pressure generating grooves are formed and on the entire inner peripheral surface.
Are formed (development / fixing process, post-resist process). Therefore, even if the etching solution E leaks to the inner peripheral surface side in the etching process, it is possible to reliably prevent the inner peripheral surface from being etched.

It should be noted that the present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention. For example, in the above-described embodiment, the pre-resist layer P
By exposing the original member 10 on which is formed the mask drum 27 to cover, only the portion of the pre-resist layer other than the groove forming position for forming the dynamic pressure generating groove is left,
A resist layer R that is corrosion resistant to the etching solution E is formed by a subsequent heat treatment.
A resist layer R by irradiating a laser beam after irradiating the resist layer R at a groove forming position where a dynamic pressure generating groove is to be formed.
May be formed.

In this case, the influence on the original member 10 is avoided,
In order to form a uniform groove for generating dynamic pressure with the etchant E, it is preferable that the laser is irradiated at a low output.
When removing the corrosion-resistant layer at the groove forming position by laser light irradiation, a heat insulating layer soluble in an etching solution may be formed on the surface of the original member 10, and a pre-resist layer P may be formed outside the heat insulating layer. By providing such a heat insulating layer, when the pre-resist layer P is removed corresponding to the dynamic pressure generating groove by laser light, heat is prevented from being transmitted to the original member 10 and radiated, and P can be efficiently removed. Examples of the heat insulating layer include silicon monoxide (SiO) and silicon dioxide (SiO2). This heat insulating layer is formed of silicon monoxide (SiO) or silicon dioxide (SiO
When formed in 2), the heat insulating layer has a thickness of 30 to 100 nm.
It is preferable to have a thickness of When the heat insulating layer is silicon monoxide (SiO) or silicon dioxide (SiO2), the heat insulating layer can be removed by an aqueous solution containing hydrogen fluoride (HF) and nitric acid (HNO3). Further, the original member 10
A light absorbing layer may be laminated between the resist layer R and the surface of the resist layer R. By providing such a light absorbing layer, it becomes possible to more effectively absorb the laser beam and efficiently remove the resist layer R corresponding to the dynamic pressure generating groove pattern. This light absorbing layer can be a chromium film, a tungsten film, a molybdenum film, a nickel-chromium film, or the like. However, since the chromium film may become chromium oxide due to oxidation and erode the substrate, it is desirable that the chromium film be completely removed after the formation of the dynamic pressure generation groove pattern. preferable. The chromium film can be removed during the etching process with an etching solution.

In each of the above embodiments and modifications,
In the resist layer formation process, a pre-resist layer is formed by a photoresist solution that can be removed by development and fixing after light irradiation, and the groove portion is removed by exposing the pre-resist layer to form a resist layer. However, a pre-resist layer forming step of forming a pre-resist layer with a photoresist solution that is made corrosion-resistant by exposure, and exposing portions other than the groove forming portion to make it corrosion-resistant and removing the groove forming portion to form a resist layer The exposure, development and fixing steps may be included. In this case, when exposing a portion other than the groove-forming portion, a light-opaque portion is formed corresponding to the groove-forming portion, and a mask drum in which the other portion is formed to be light-transmissive is mounted, and from the outer peripheral surface. By irradiating light,
Exposure can be made to portions other than the groove forming portion. In order to form a resist layer also on the inner peripheral surface, a separate step such as exposure from the inner peripheral surface side is required. In each of the above embodiments and modifications, the original member 10 fixed to the support shaft 20 is used.
Is immersed in a photoresist solution S to adhere the solution S to the surface of the original member 10. However, the present invention is not limited to this, and vapor deposition, coating, spraying, or the like may be used.

In each of the above-described embodiments and modifications, after the radial dynamic pressure generating groove 152b is formed on the peripheral surface of the original member 10, the thrust dynamic pressure generating groove 152a is formed on the end surface of the original member 10. After forming a dynamic pressure generating groove in the thrust direction on the end face of each raw material member 10, the raw material member 10 is fixed to the support shaft 20, and a dynamic pressure in the radial direction is formed by a series of strokes. A generation groove may be formed.

In each of the above-described embodiments and modifications, both the radial dynamic pressure generating groove 152 and the thrust dynamic pressure generating groove 152a are formed in the bearing ring 152. A thrust-direction dynamic pressure generating groove 15a is formed in a fixed columnar member. A dynamic pressure generating groove 152 is formed only in a radial dynamic pressure deriving groove 152 in an original member of a bearing ring used in a motor or the like. It can also be a method.

[0030]

As described above, according to the dynamic pressure generating groove forming method of the present invention, when forming the dynamic pressure generating groove on the outer peripheral surface of the cylindrical member, only the outer peripheral surface is exposed. In view of this, a plurality of tubular members are fixed to a common support shaft in the axial direction, and a resist layer is formed and etched while the tubular members are collectively handled, and the resist layer is removed. Therefore, it is easy to handle during and between each stroke, and it is possible to form a dynamic pressure generating groove in many cylindrical members with a small amount of labor, and to reduce the labor and time for processing. The grooves for generating dynamic pressure can be formed at a low cost.

[Brief description of the drawings]

FIG. 1 is an explanatory view conceptually showing each step of a dynamic pressure generating groove forming method according to a first embodiment of the present invention.

FIG. 2 is an explanatory view conceptually showing each step of a method for forming a groove for generating dynamic pressure, following each step of FIG. 1;

FIG. 3 is a side view showing a support shaft used in a dynamic pressure generating groove forming method according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of a prior art motor using a dynamic pressure bearing in which a dynamic pressure generating groove is formed by the dynamic pressure generating groove forming method of the present invention.

5 is a perspective view showing a state in which a bearing ring of the motor of FIG. 4 is fixed to a support shaft.

[Explanation of symbols]

 Reference Signs List 10 original member 20 support shaft 20a groove 21 retaining portion 21a communication hole 22 thread 23 groove 24 nut 25 retaining plate 25a passage hole 27 mask drum 271 light transmitting portion 272 light impermeable portion E etching solution P pre-resist layer R resist Layer S Photoresist solution T Table

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Naoki Kawawada 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba SII Micro Precision Co., Ltd. (72) Inventor Atsushi Ota 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba No. S-II Micro Precision Co., Ltd. F-term (reference) 3J011 AA20 BA03 CA02 DA02 4K057 WB02 WB05 WB17 WE02 WE04 WE08 WE12 WN06 5H607 AA00 BB01 DD03 GG12

Claims (5)

[Claims] 1. An alignment step of fixing a plurality of cylindrical members having a hollow portion penetrating in an axial direction in a state of being inserted through a common shaft, and said fixing step fixed to the shaft after the alignment step. On the outer peripheral surface of the cylindrical member, in addition to the groove forming position for forming the dynamic pressure generating groove, a resist layer forming step of forming a resist layer that is resistant to etching liquid, and after the resist layer forming step, An etching step of immersing the cylindrical member in the etching solution to etch the groove forming portion; and a resist layer removing step of removing the resist layer remaining on the cylindrical member after the etching step. Forming a groove for generating dynamic pressure. 2. The method of forming a resist layer, comprising: attaching a photoresist solution that can be removed by development and fixing after light irradiation onto the entire outer peripheral surface of the cylindrical member fixed to the shaft; A pre-resist layer forming step of forming a pre-resist layer by performing a heat treatment at a predetermined temperature for a predetermined time, and after the pre-resist layer forming step, a portion of a groove forming position for forming a dynamic pressure generating groove is exposed, An exposure, development, and fixing step of removing the pre-resist layer at the groove forming position and fixing a portion other than the groove forming position by development and fixing, and a residual and fixed pre-pressing step after the exposure, development, and fixing step. 2. The method according to claim 1, further comprising: a post-resist step of forming the resist layer by leaving the resist layer at a predetermined temperature for a predetermined time to cause corrosion. 3. The exposing / developing / fixing step includes forming a light transmitting portion corresponding to the groove forming portion of all of the plurality of cylindrical members fixed to the shaft, and excluding the light transmitting portion. Mounting a mask drum having a light-opaque shape on a cylindrical drum around a plurality of the cylindrical members fixed to the shaft, fixing the position with respect to the cylindrical member; And an exposure step of irradiating the cylindrical member with light from outside the mask drum to expose the portion of the pre-resist layer at the groove forming position after the mask drum mounting step, After the exposure step, developing and removing the exposed portion of the pre-resist layer at the groove forming position and fixing the pre-resist layer at the portion other than the unexposed groove forming position.
The method according to claim 2, further comprising a fixing step. 4. The pre-resist layer forming step according to claim 2, wherein the pre-resist layer is formed also on inner peripheral surfaces of the plurality of cylindrical members. A method for forming grooves for generating dynamic pressure. 5. The aligning step includes fixing the tubular member to the shaft having a passage communicating the outside of the plurality of tubular members and the hollow portion, and the pre-resist layer forming step includes: 5. The method according to claim 4, wherein the cylindrical member fixed to the shaft is immersed in the photoresist solution, and the solution is also adhered to the inner peripheral surface through the passage of the shaft. Method for forming pressure generating grooves.