U.S. patent application number 11/405631 was filed with the patent office on 2007-02-22 for dynamic bearing manufacturing method.
This patent application is currently assigned to DELTA ELECTRONICS, INC.. Invention is credited to Lee-Long Chen, Chien-Hsiung Huang, Shih-Ming Huang, Wen-Shi Huang.
Application Number | 20070039185 11/405631 |
Document ID | / |
Family ID | 37765117 |
Filed Date | 2007-02-22 |
United States Patent
Application |
20070039185 |
Kind Code |
A1 |
Chen; Lee-Long ; et
al. |
February 22, 2007 |
Dynamic bearing manufacturing method
Abstract
A method of manufacturing a dynamic bearing comprises providing
a bearing having a through hole. A photoresist is coated on an
inner wall of the through hole. An ultraviolet lamp capable of
inserting into the through hole is provided. A mask having patterns
of pressure-generating grooves is attached to the surface of the
ultraviolet lamp. The ultraviolet lamp is inserted into the through
hole to perform an exposure process with the mask. The exposed
portions of photoresist are developed to appear portions of the
inner wall underneath. The appeared portions of the inner wall are
etched to form grooves on the bearing, and finally, the photoresist
remaining on the inner wall of the through hole is stripped.
Inventors: |
Chen; Lee-Long; (Taoyuan
Hsien, TW) ; Huang; Chien-Hsiung; (Taoyuan Hsien,
TW) ; Huang; Shih-Ming; (Taoyuan Hsien, TW) ;
Huang; Wen-Shi; (Taoyuan Hsien, TW) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
DELTA ELECTRONICS, INC.
|
Family ID: |
37765117 |
Appl. No.: |
11/405631 |
Filed: |
April 18, 2006 |
Current U.S.
Class: |
29/898.02 |
Current CPC
Class: |
F16C 17/026 20130101;
F16C 33/14 20130101; F16C 2223/42 20130101; F16C 2223/40 20130101;
F16C 2220/62 20130101; C23F 1/14 20130101; Y10T 29/49639 20150115;
F16C 33/1025 20130101; C23F 1/44 20130101; F16C 2220/20 20130101;
F16C 2223/44 20130101; F16C 2220/82 20130101 |
Class at
Publication: |
029/898.02 |
International
Class: |
B21K 1/10 20060101
B21K001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 19, 2005 |
TW |
94128355 |
Claims
1. A method of manufacturing a dynamic bearing, comprising the
steps of: providing a bearing having a through hole; coating a
photoresist on an inner wall of the through hole of the bearing;
inserting an ultraviolet lamp having at least one pattern of groove
into the through hole and performing an exposure process; removing
the photoresist to expose portions of the inner wall by a
developer; and etching the exposed portions of the inner wall to
form at least one groove by an etchant.
2. The method of manufacturing a dynamic bearing as claimed in
claim 1, wherein the pattern of groove is formed on a mask attached
to the surface of the ultraviolet lamp.
3. The method of manufacturing a dynamic bearing as claimed in
claim 1, wherein the mask further comprises a pattern of oil
reservoir.
4. The method of manufacturing a dynamic bearing as claimed in
claim 1, wherein the shape of the pattern of groove comprises
V-shape, substantially-modified-X-shape, fish bone shape, twill or
straight stripe shape.
5. The method of manufacturing a dynamic bearing as claimed in
claim 1, wherein the bearing is baked after the inner wall is
coated with the photoresist.
6. The method of manufacturing a dynamic bearing as claimed in
claim 1, wherein the bearing and the through hole thereof are
formed by cutting, turning or powder sintering.
7. The method of manufacturing a dynamic bearing as claimed in
claim 1, wherein the photoresist is coated on the inner wall by
spray coating, dipping, spin coating or centrifugal coating.
8. The method of manufacturing a dynamic bearing as claimed in
claim 1, wherein the ultraviolet lamp comprises a cold cathode
fluorescent lamp or optical fiber illuminant.
9. The method of manufacturing a dynamic bearing as claimed in
claim 1, wherein the inner wall of the bearing is cleaned by water
after the developing step.
10. The method of manufacturing a dynamic bearing as claimed in
claim 1, wherein the inner wall of the bearing is cleaned by water
after the etching step.
11. The method of manufacturing a dynamic bearing as claimed in
claim 1, wherein a stripping solution is used to remove the
residual photoresist on the inner wall after the etching step.
12. The method of manufacturing a dynamic bearing as claimed in
claim 1, wherein the bearing comprises copper or metal.
13. The method of manufacturing a dynamic bearing as claimed in
claim 1, wherein the photoresist is a positive photoresist.
14. The method of manufacturing a dynamic bearing as claimed in
claim 13, wherein the photoresist comprises polyimide, diazonium
salt, or sulfonamide chlorine.
15. The method of manufacturing a dynamic bearing as claimed in
claim 13, wherein the pattern of groove is transparent, while the
other portion of the mask is opaque.
16. The method of manufacturing a dynamic bearing as claimed in
claim 15, wherein the ultraviolet lamp emits ultraviolet light
having the wavelength ranging from 350 nm to 450 nm.
17. The method of manufacturing a dynamic bearing as claimed in
claim 16, wherein the developer comprises sodium hydroxide
solution.
18. The method of manufacturing a dynamic bearing as claimed in
claim 17, wherein the etchant comprises ferric chloride, cupric
chloride or ammonium sulfide solution.
19. The method of manufacturing a dynamic bearing as claimed in
claim 18, wherein after the etching step, the residual photoresist
on the inner wall is removed by alcohol.
20. A method of manufacturing a dynamic bearing, comprising the
steps of: providing a bearing having a through hole, and an
ultraviolet lamp; applying a photoresist on an inner wall of the
through hole of the bearing; attaching a mask having patterns of at
least one pressure-generating groove and an oil reservoir on the
surface of the ultraviolet lamp; inserting the ultraviolet lamp
into the through hole to perform an exposure process; removing the
photoresist to expose portions of the inner wall; etching the
exposed portions of the inner wall to form grooves and oil
reservoir thereon; and stripping the photoresist remaining on the
inner wall.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a method of manufacturing a dynamic
bearing, and in particular to a method of fabricating a dynamic
bearing utilizing photolithography.
[0003] 2. Description of the Related Art
[0004] A dynamic bearing comprises fine pressure-generating grooves
on the inner walls thereof. As the axle of a motor spins, lubricant
in the pressure-generating grooves is drawn to distribute between
axle and the bearing and generate dynamical pressure therebetween,
which reduces the friction between the axle and the bearing and
eliminates the noise due to the friction. The pressure-generating
grooves on the inner wall of the bearing, however, are difficult to
be fabricated because of the minute scale of width and depth
thereof. The costs of conventional manufacturing methods such as
cutting, rolling, injection, or combination etc. are very high
because these methods need special processing tools and skills. In
addition, pressure-generating grooves processed by cutting
processing often cause breach at the turning point and have
inconsistent depth and width. Furthermore, the expensive processing
machine and fragile cutting tools cannot be effectively and
efficiently applied to mass production.
BRIEF SUMMARY OF THE INVENTION
[0005] The invention provides a method of manufacturing a dynamic
bearing by photolithography to simplify the formation of
pressure-generating grooves on the inners wall of bearing.
[0006] According to the invention, a method of manufacturing a
dynamic bearing, comprises the steps of: providing a bearing having
a through hole; applying a photoresist .on an inner wall of the
through hole of the bearing; providing an ultraviolet lamp capable
of entering into the through hole; attaching a mask having patterns
of pressure-generating grooves to the surface of the ultraviolet
lamp; inserting the ultraviolet lamp into the through hole to
expose the photoresist through the mask; removing the exposed
portions of photoresist to make its underneath portions of the
inner wall appear; etching the appeared portions of the inner wall
to form grooves; and stripping the remaining photoresist from the
inner wall of the bearing.
[0007] Preferably, the bearing is made of copper or metal and is
baked after the photoresist is applied on its inner wall.
[0008] The patterns of pressure-generating grooves of the mask are
transparent and the other portion of the mask is opaque.
[0009] The mask can further comprise a pattern of an oil reservoir
thereon for forming an oil reservoir on the inner wall of the
bearing.
[0010] The method of the present invention can reduce costs as
result of automated or semi-automated mass production, and form the
identical and uniform grooves in any kinds of shapes in the inner
wall of a bearing with ease.
[0011] A detailed description is given in the following with
reference to the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention can be more fully understood by reading the
subsequent detailed description and examples with references made
to the accompanying drawings, wherein:
[0013] FIG. 1 is a cross section of a bearing according to an
embodiment of the invention;
[0014] FIG. 2 is a cross section of a bearing coated with
photoresist on the inner wall thereof according to an embodiment of
the invention;
[0015] FIG. 3 shows a lamp used in an exposure process according to
an embodiment of the invention;
[0016] FIG. 4 is a diagram of an exposure process according to an
embodiment of the invention;
[0017] FIG. 5 is a diagram of a bearing after developing process
according to an embodiment of the invention; and
[0018] FIG. 6 is a diagram of a bearing after etching and stripping
process according to an embodiment of the invention.
DETAILED DESCRIPTION OF INVENTION
[0019] According to the invention, a method of manufacturing
dynamic bearing at first is to form a desired shape of a bearing
having a through hole by cutting or turning or by powder sintering
way. The bearing is preferably made of copper.
[0020] An inner wall 10 defining the through hole is coated with a
photoresist 20 uniformly, as shown in FIG. 2, by spray coating,
dipping, spin coating or centrifugal coating. The photoresist 20
coated on the inner wall 10 comprises polyimide, diazonium salt, or
sulfonamide chlorine. In this embodiment of the invention, the
photoresist 20 coated on the inner wall 10 is a kind of positive
photoresist, for example "Electrolube PRP-200."
[0021] Then, the photoresist 20 coated on the inner wall 10 is
dried by baking process for securing the adhesion between the inner
wall 10 and the photoresist 20. As shown in FIG. 3, an ultraviolet
lamp 30 with a mask 40 attached on the surface thereof is provided.
The mask 40 comprises patterns of pressure-generating grooves 401
and an oil reservoir 402 thereon. The ultraviolet lamp 30 is
preferably a cold cathode fluorescent lamp or an optical fiber
illuminant, which can emit ultraviolet light having wavelength
ranging from 350 nm to 450 nm. With positive photoresist in this
embodiment, the patterns of pressure-generating grooves 401 and oil
reservoir 402 are transparent on the mask and the other portion
thereof is opaque. In this embodiment, the groove on the mask is
V-shaped. As shown in FIG. 4, after baking process, the ultraviolet
lamp 30 with the mask 40 attached thereon is inserted into the
through hole of the bearing, and activated to emit ultraviolet
light to execute an exposure process. During the exposure process,
a part of the photoresist 20 is sensitized by the ultraviolet light
emitted from the ultraviolet lamp 30 through the patterns on the
mask 40.
[0022] After the exposure process, as shown in FIG. 5, the
ultraviolet lamp 30, is removed, and the exposed photoresist is
removed by a developer to make the underneath portions of the inner
wall 10 appear. The concentration of the developer is determined by
the type of photoresist. In this embodiment, NaOH solution is used
to serve as a developer.
[0023] After the developing process, the bearing is cleaned by
water, and then the appeared portions of the inner wall are etched
to form grooves 12 and an oil reservoir 13. The etchant can
comprise ferric chloride, cupric chloride or ammonium sulfide
solution.
[0024] After the etching process, the bearing is cleaned by water,
and the photoresist remaining on the inner wall is stripped by a
stripping solution such as alcohol, and then is cleaned by water.
The finished dynamic bearing of the invention is shown in FIG.
6.
[0025] The feature of the invention is to form the
pressure-generating grooves on the inner wall of a bearing by
photolithography, so the solutions used in this invention are not
limited. In addition, the grooves on the inner wall are also not
limited in any shape, and it can be in fish bone shape,
substantially-modified-X-shape, twill or straight stripe shape.
[0026] Finally, while the invention has been described by way of
example and in terms of preferred embodiment, it is to be
understood that the invention is not limited thereto. On the
contrary, it is intended to cover various modifications and similar
arrangements as would be apparent to those skilled in the art.
Therefore, the scope of the appended claims should be accorded the
broadest interpretation so as to encompass all such modifications
and similar arrangements.
* * * * *