U.S. patent application number 11/889946 was filed with the patent office on 2007-12-13 for method for manufacturing bearing assembly.
This patent application is currently assigned to DELTA ELECTRONICS, INC.. Invention is credited to Heng-Chung Chang, Huang-Kun Chen, Wen-Shi Huang, Cheng-Chang Lee, Tai-Kang Shing, Zong-Ting Yuan.
Application Number | 20070283563 11/889946 |
Document ID | / |
Family ID | 38820417 |
Filed Date | 2007-12-13 |
United States Patent
Application |
20070283563 |
Kind Code |
A1 |
Lee; Cheng-Chang ; et
al. |
December 13, 2007 |
Method for manufacturing bearing assembly
Abstract
The invention provides a method for manufacturing bearing
assembly. The method comprises: coating a photoresist on an inner
wall of a through hole of a bearing; inserting an ultraviolet lamp
having a transparent groove pattern thereon into through hole and
performing exposure process so as to photosensitize the photoresist
corresponding to the groove pattern; removing the ultraviolet lamp
and cleaning the photosensitized portion of the photoresist by
developer; etching the inner wall not covered with the photoresist
by an etchant or forming a deposited layer on the inner wall not
covered with the photoresist; removing the photoresist reminding on
the inner wall by a stripping agent so as to complete the method
for manufacturing a dynamic bearing. The method is also proved to a
surface of a shaft to manufacture the dynamic bearing.
Inventors: |
Lee; Cheng-Chang; (Taoyuan
Hsien, TW) ; Yuan; Zong-Ting; (Taoyuan Hsien, TW)
; Chang; Heng-Chung; (Taoyuan Hsien, TW) ; Chen;
Huang-Kun; (Taoyuan Hsien, TW) ; Shing; Tai-Kang;
(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: |
38820417 |
Appl. No.: |
11/889946 |
Filed: |
August 17, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11405631 |
Apr 18, 2006 |
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11889946 |
Aug 17, 2007 |
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Current U.S.
Class: |
29/898.02 |
Current CPC
Class: |
F16C 33/14 20130101;
F16C 2223/60 20130101; C23F 1/14 20130101; C25D 5/022 20130101;
C23F 1/02 20130101; F16C 17/026 20130101; F16C 2220/20 20130101;
F16C 3/02 20130101; Y10T 29/49639 20150115; G03F 7/24 20130101;
C25D 7/10 20130101; F16C 2220/62 20130101; F16C 2223/42 20130101;
C25D 11/04 20130101; F16C 17/02 20130101; F16C 2220/82 20130101;
F16C 33/107 20130101; F16C 2223/44 20130101; F16C 2223/70 20130101;
F16C 2223/40 20130101 |
Class at
Publication: |
029/898.02 |
International
Class: |
B21K 1/10 20060101
B21K001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 17, 2006 |
TW |
95130275 |
Claims
1. A method for manufacturing a bearing, comprising the steps of:
providing a bearing having a through hole; coating a photoresist on
an inner wall of the through hole; 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 forming deposited
layers on the exposed portions of the inner wall so that at least
one groove is formed between the two adjacent deposited layers.
2. The method as recited in claim 1, wherein the groove comprises V
shape, fishbone, chevron or twill pattern.
3. The method as recited in claim 1, wherein the pattern of groove
is formed by attaching a mask to the ultraviolet lamp.
4. The method as recited in claim 3, wherein the mask comprises a
pattern of oil reservoir.
5. The method as recited in claim 3, wherein the photoresist is a
positive photoresist, and wherein the ultraviolet lamp emits
ultraviolet light having the wavelength ranging from 350 nm to 450
nm, the pattern of groove is opaque to the ultraviolet light, while
the other portion of the mask is transparent.
6. The method as recited in claim 3, wherein the photoresist is a
negative photoresist, and wherein the ultraviolet lamp emits
ultraviolet light having the wavelength ranging from 350 nm to 450
nm, the pattern of groove is transparent to the ultraviolet light,
while the other portion of the mask is opaque.
7. The method as recited in claim 1, wherein the bearing comprises
copper, brass, bronze, aluminum, aluminum alloys or alumina
ceramic.
8. The method as recited in claim 7, wherein the deposited layer is
formed by electroplating, sputtering, and a chemical reaction.
9. The method as recited in claim 8, wherein the deposited layer
comprises nickel-cobalt alloy, nickel-phosphor alloy,
nickel-cobalt-phosphor alloy or a wear resistant material.
10. The method as recited in claim 8, wherein the chemical reaction
is dipping the bearing in oxalic acid solvent following by anode
oxidation treatment to form aluminum oxide as the deposited
layer.
11. The method as recited in claim 1, wherein the ultraviolet lamp
is a cold cathode lamp or optical fiber illuminant.
12. A method for manufacturing a shaft, comprising the steps of:
providing a shaft; coating a photoresist on a surface of the shaft;
providing an ultraviolet lamp having at least one pattern of groove
as a mask and performing an exposure process to the shaft; removing
the photoresist to expose portions of surface of the shaft by a
developer; and etching the exposed portions of the surface of the
shaft to form at least one groove on the shaft.
13. The method as recited in claim 12, wherein the photoresist is a
positive photoresist, and wherein the ultraviolet lamp emits
ultraviolet light having the wavelength ranging from 350 nm to 450
nm, the pattern of groove is transparent to the ultraviolet light,
while the other portion of the mask is opaque.
14. The method as recited in claim 12, wherein the photoresist is a
negative photoresist, and wherein the ultraviolet lamp emits
ultraviolet light having the wavelength ranging from 350 nm to 450
nm, the pattern of groove is opaque to the ultraviolet light, while
the other portion of the mask is transparent.
15. The method as recited in claim 12, wherein the groove comprises
V shape, fishbone, chevron or twill pattern.
16. The method as recited in claim 12, wherein the shaft comprises
copper, brass, bronze, aluminum or alloys thereof.
17. A method for manufacturing a shaft, comprising the steps of:
providing a shaft; coating a photoresist on a surface of the shaft;
providing an ultraviolet lamp having at least one pattern of groove
as a mask and performing an exposure process to the shaft; removing
the photoresist to expose portions of surface of the shaft by a
developer; and forming deposited layers on the exposed portions of
the inner wall so that at least one groove is formed between the
two adjacent deposited layers.
18. The method as recited in claim 17, wherein the groove comprises
V shape, fishbone, chevron or twill pattern.
19. The method as recited in claim 17, wherein the shaft comprises
copper, brass, bronze, aluminum or alloys thereof.
20. The method as recited in claim 17, wherein the photoresist is a
positive photoresist, and wherein the ultraviolet lamp emits
ultraviolet light having the wavelength ranging from 350 nm to 450
nm, the pattern of groove is opaque to the ultraviolet light, while
the other portion of the mask is transparent.
21. The method as recited in claim 17, wherein the photoresist is a
negative photoresist, and wherein the ultraviolet lamp emits
ultraviolet light having the wavelength ranging from 350 nm to 450
nm, the pattern of groove is transparent to the ultraviolet light,
while the other portion of the mask is opaque.
22. The method as recited in claim 17, wherein the deposited layer
is formed by electroplating, sputtering, and a chemical
reaction.
23. The method as recited in claim 22, wherein the deposited layer
comprises nickel-cobalt alloy, nickel-phosphor alloy,
nickel-cobalt-phosphor alloy or a wear resistant material.
24. The method as recited in claim 22, wherein the chemical
reaction is dipping the bearing in oxalic acid solvent following by
anode oxidation treatment to form aluminum oxide as the deposited
layer.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation-In-Part of pending U.S.
patent application Ser. No. 11/405,631, filed Apr. 18, 2006 and
entitled "DYNAMIC BEARING MANUFACTURING METHOD", and claims
priority under 35 U.S.C. .sctn.119(a) on Patent Application No.
095130272 filed in Taiwan, Republic of China on Aug. 17, 2006, the
entire contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a method for manufacturing bearing
assembly, and more particularly, to a method for manufacturing
bearing assembly with pressure-generating grooves in
photolithography process.
[0004] 2. Description of the Related Art
[0005] 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 INVENTION
[0006] Ameliorating the aforementioned problems, the invention
provides a method for manufacturing bearing assembly in
photolithography process.
[0007] According to the invention, a method of manufacturing a
bearing assembly is provided. An exemplary embodiment of the method
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.
[0008] According to the exemplary embodiment, the bearing is
preferably made of copper.
[0009] According to the exemplary embodiment, the photoresist is
preferably coated by spray coating, dipping, spin coating or
centrifugal coating.
[0010] According to the exemplary embodiment, after the photoresist
has been coated, a baking step is preferably executed to cure the
photoresist.
[0011] According to the exemplary embodiment, the ultraviolet lamp
preferably comprises cold cathode fluorescent lamp (CCFL) or light
optical fiber.
[0012] According to the exemplary embodiment, a portion of the
mask, the patterns of pressure-generating grooves located, is
transparent and the other portion is opaque.
[0013] According to the exemplary embodiment, the mask does not
only have the groove patterns, but also have a oil reservoir
pattern to simultaneously form grooves and the oil reservoir on the
inner wall of the through hole in the bearing.
[0014] According to the exemplary embodiment, the mask preferably
comprises a slice attached to the ultraviolet lamp, or a metal
pattern directly formed on the wall of ultraviolet lamp.
[0015] According to the exemplary embodiment, a portion of the
mask, the groove patterns located, is opaque and the other portion
thereof is transparent. An exposed portion of photoresist, such as
positive photoresist, is removed by a developer, a deposited layer
is then formed on a portion of the inner wall where the photoresist
has been removed. The residual positive photoresist on the inner
wall is removed by stripping agent to form the grooves between the
two adjacent deposited layers. Washing the bearing by water is to
complete dynamic bearing.
[0016] According to the exemplary embodiment, the deposited layer
is preferably made of a wear resistant material which is different
from the bearing.
[0017] According to the exemplary embodiment, the deposited layer
on the portion of the inner wall which is not covered with
photoresist is preferably formed by electroplating, sputtering,
chemical reaction, or any other suitable manner for forming
deposited layers.
[0018] According to the exemplary embodiment, a negative
photoresist can also be applied to coat on the inner wall to
manufacture the bearing. Differences of the steps between examples
of using negative and positive photoresists are the following:
while the mask with the pattern of grooves is opaque, a portion of
the inner wall without covering the photoresist is etched by
etchant to a desirable depth to form the bearing with grooves; and
while the mask with the pattern of grooves is transparent, a
deposited layer is formed on the portion of the inner wall, where
the photoresist not covered, by electroplating, sputtering, a
chemical reaction, or any other suitable manner for forming
deposited layer, to form a dynamic bearing having grooves formed
between the two adjacent deposited layers.
[0019] The method for manufacturing the bearing assembly according
to the invention, a surface of a shaft can be processed by
photolithography process to eliminate difficulty in manufacturing
fine grooves of small bearing assembly.
[0020] According to the method of manufacturing bearing assembly,
an exemplary embodiment of the method comprises the steps of:
providing a shaft; applying a positive photoresist on a surface of
the shaft; providing an ultraviolet lamp with circular shape, and
the inner surface thereof attached a mask having patterns of
grooves; inserting the shaft into the ultraviolet lamp to expose
and produce a photosensitized portion of the positive photoresist
corresponding to a transparent portion of the mask; taking the
shaft out the lamp and removing the exposed portion of the positive
photoresist on the surface of the shaft by a developer; etching the
surface of the shaft without covered with the positive photoresist
to form a desirable depth; stripping the remaining positive
photoresist from the surface of the shaft; and washing the shaft by
water to complete manufacture of a dynamic bearing having
grooves.
[0021] According to the exemplary embodiment, the shaft is
preferably made of copper or alloys thereof.
[0022] According to the exemplary embodiment, the positive
photoresist is preferably coated on the surface of the shaft by
spray coating, dipping, spin coating or centrifugal coating.
Preferably, a baking step is executed to cure the positive
photoresist after the coating step.
[0023] According to the exemplary embodiment, the groove pattern of
the mask is transparent and the other pattern thereof is
opaque.
[0024] According to the exemplary embodiment, the mask does not
only have the groove patterns, but also have a oil reservoir
patterns to simultaneously form grooves and the oil reservoir on
the surface of the shaft.
[0025] According to the exemplary embodiment, a portion of the mask
with the patterns of grooves is opaque and the other portion
thereof is transparent. An exposed portion of positive photoresist
is removed by a developer to form an appeared surface of the shaft
and a deposited layer is then formed on the appeared surface of the
shaft. The positive photoresist reminding on the surface of the
shaft is removed by a stripping agent to form the grooves between
the two adjacent deposited layers. Washing the bearing by water is
to complete a dynamic bearing.
[0026] According to the exemplary embodiment, the deposited layer
is preferably made of a wear resistant material and can be a
material which is different from or the same as the bearing.
[0027] According to the exemplary embodiment, the deposited layer
on the appeared surface of the shaft is preferably formed by
electroplating, sputtering, chemical reaction, or any other
suitable manner.
[0028] According to the exemplary embodiment, a negative
photoresist can be in place of the positive photoresist to
manufacture the bearing assembly.
[0029] In the embodiment, differences of the steps between examples
of using negative and positive photoresists are the following:
while the mask with the pattern of grooves is opaque, a portion of
the surface of the shaft without covering the photoresist is etched
by an etchant to a desirable depth to form the bearing having
grooves; and while the mask with the pattern of grooves is
transparent, a deposited layer is formed on the portion of the
surface of the shaft where the photoresist does not cover thereon
by electroplating, sputtering, chemical reaction, or any other
suitable manner for forming deposited layer so that the bearing
having grooves formed between the two adjacent deposited layer.
[0030] The method for manufacturing the bearing of the invention,
reduces equipment cost, and enables high the throughput. The method
is introduced into automation or semi-automation. The dimensions of
the formed groove are equal. Any groove shape is formed easily. A
typical operator can easily perform the method. Because the
manufacturing cost is lower, a medium-small ball bearing and solid
lubricating bearing is replaced by a bearing manufactured according
to the method of the invention.
[0031] A detailed description is given in the following embodiments
with reference to the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0032] The invention can be more fully understood by reading the
subsequent detailed description and examples with references made
to the accompanying drawings, wherein:
[0033] FIG. 1 is a cross section of a bearing according to a first
embodiment of the invention;
[0034] FIG. 2 is a cross section of a bearing coated with
photoresist on the inner wall thereof according to the first
embodiment of the invention;
[0035] FIG. 3 shows a lamp used in an exposure process according to
the first embodiment of the invention;
[0036] FIG. 4 is a diagrammatic view of an exposure process
according to the first embodiment of the invention;
[0037] FIG. 5 is a diagrammatic view of a bearing after developing
process according to the first embodiment of the invention;
[0038] FIG. 6 is a diagrammatic view of a bearing after etching and
stripping process according to the first embodiment of the
invention.
[0039] FIG. 7 is a diagrammatic view of the exposure lamp according
to a second embodiment of the invention;
[0040] FIG. 8 is a diagrammatic view of a photolithography step
according to the second embodiment of the invention;
[0041] FIG. 9 is a diagrammatic view of the bearing after
development according to the second embodiment of the
invention;
[0042] FIG. 10A is a diagrammatic view of the bearing after
electroplating according to the second embodiment of the
invention;
[0043] FIG. 10B is a fragmentary sectional view of the bearing in
FIG. 10A;
[0044] FIGS. 11A and 11B are diagrammatic views of the bearing in
FIGS. 10A and 10B after stripping, respectively;
[0045] FIGS. 12 and 13 are fragmentary sectional views of the
deposited layer according to the second embodiment of the invention
and formed by adjusting different electroplating parameter,
respectively;
[0046] FIG. 14A is a diagrammatic view of the bearing after
sputtering according to a third embodiment of the invention;
[0047] FIG. 14B is a fragmentary sectional view of the bearing in
FIG. 14A;
[0048] FIGS. 15A and 15B are diagrammatic views of the bearing in
FIGS. 14A and 14B after stripping, respectively;
[0049] FIG. 16A is a diagrammatic view of bearing after chemical
reaction according to a fourth embodiment of the invention:
[0050] FIG. 16B is a fragmentary sectional view of the bearing in
FIG. 16A;
[0051] FIGS. 17A and 17B are diagrammatic views of the bearing in
FIGS. 16A and 16B, respectively, after stripping;
[0052] FIG. 18 is a diagrammatic view illustrating steps for
manufacturing a shaft according to a fifth embodiment of the
invention;
[0053] FIG. 19 is a diagrammatic view illustrating steps for
manufacturing the shaft according to a sixth embodiment of the
invention;
[0054] FIG. 20 is a diagrammatic view illustrating steps for
manufacturing the shaft according to a seventh embodiment of the
invention;
[0055] FIG. 21 is a diagrammatic view illustrating steps for
manufacturing the shaft according to a eighth embodiment of the
invention;
[0056] FIG. 22 is a diagrammatic view illustrating steps for
manufacturing the shaft according to a ninth embodiment of the
invention; and
[0057] FIG. 23 is a diagrammatic view illustrating steps for
manufacturing the shaft according to a tenth embodiment of the
invention.
DETAILED DESCRIPTION OF INVENTION
[0058] The following description is of the best-contemplated mode
of carrying out the invention. This description is made for the
purpose of illustrating the general principles of the invention and
should not be taken in a limiting sense. The scope of the invention
is best determined by reference to the appended claims.
First Embodiment
[0059] According to the invention, a method of manufacturing
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, as shown in FIG. 1, is preferably made of copper.
[0060] 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."
[0061] 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.
[0062] 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.
[0063] After the developing process, the bearing is cleaned by
water. The appeared inner wall 10, the portion of the inner wall 10
uncovering the photoresist 20, is then etched by an etchant to form
grooves 12 and an oil reservoir 13 with desirable dimensions. The
etchant can comprise ferric chloride, cupric chloride or ammonium
sulfide solution.
[0064] After the etching process, the bearing is cleaned by water,
and the photoresist 20 remaining on the inner wall 10 is stripped
by a stripping solution such as alcohol. Then, the bearing is
cleaned by water to remove the solutions and expose the grooves 12
and the oil reservoir 13. The finished bearing of the invention is
shown in FIG. 6.
[0065] 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.
Second Embodiment
[0066] According to a second embodiment of the invention, a method
for manufacturing the bearing at first is to form a desired shape
of a bearing having a through hole and then coat a photoresist on
an inner wall of the through hole in the bearing by the similar
steps to the first embodiment, as shown in FIGS. 1 and 2.
Preferably, the bearing 1 is made of copper or alloys thereof. The
photoresist 20 is preferably a positive photoresist such as, but
not limited to, photosensitive polyimide (PSPI) photoresist, diazo
photoresist, chlorine sulfonamide, naphthoquinone diazide
derivative or novolakresin derivative, and can be coated by spray
coating, dipping, spin coating or centrifugal coating. In the
second embodiment, the photoresist 20 is AZP-4620 comprising of
naphthoquinone diazide derivative and novolakresin derivative
produced by Clariant Incorporation.
[0067] The photoresist 20 coated on the inner wall 10 can be cured
by baking. Alternatively, the photoresist 20 can be cured by
natural drying at room temperature.
[0068] Furthermore, as shown in FIG. 7, a lamp 30a, also referred
to as a ultraviolet lamp, capable of passing through the through
hole and emitting light in ultraviolet spectrum, wherein the lamp
30a having a mask 40a with a pressure-generating groove pattern
401a thereon, is provided. Specifically, the mask 40a can be a
slice having the pressure-generating groove pattern 401a thereon,
attached to the lamp 30a, or have metal pattern with the
pressure-generating groove pattern 401a thereon, for example
chromium (Cr), formed on the lamp 30a. The lamp 30a is capable of
emitting a light for photosensitizing the photoresist 20. In this
embodiment, the light is preferably ultraviolet having a wavelength
of between about 350 nm and 450 nm. In this embodiment, a portion
of the mask 40a, where the pressure-generating groove pattern 401a
located, is opaque. The pressure-generating groove pattern 401a, as
shown in FIG. 7, is only an exemplary embodiment, its shape can be
varied with design and is thus not limited thereto.
[0069] As shown in FIG. 8, the lamp 30a is placed inside the
through hole of the bearing body 1 after curing and baking, the
power thereof is then turned on to emit ultraviolet light so that
the photoresist 20 can be exposed. Thus, a portion of the
photoresist 20 corresponding to a transparent portion of the mask
40a is photosensitized.
[0070] After exposing, the lamp 30a is then removed. The
photosensitized portion of the positive photoresist 20 is removed
by a developer to appear a portion of the inner wall 10, as shown
in FIG. 9. In this embodiment, the developer can be, for example
AZ-300 made of tetramethyl ammonium hydroxide, produced by Clariant
incorporation. Note that the composition and concentration of the
developer depends on the material of the photoresist, thus is not
limited to the described example.
[0071] Referring to FIG. 10A, the appeared portion of the inner
wall 10, without covered with the photoresist 20, is coated with a
wear-resistant material, for example nickel-cobalt (NiCo) alloy,
nickel-phosphor (NiP) alloy or nickel-cobalt-phosphor (NiCoP)
alloy, by electroplating to form a deposited layer 50. FIG. 10B is
a fragmentary sectional view of the bearing in FIG. 10A.
[0072] In FIG. 11A, the photoresist 20 remaining on the inner wall
10 is stripped by a stripping solution to form a desirable,
pressure-generating groove 12a between the two adjacent deposited
layer 50. In this embodiment, the stripping agent can be acetone.
Thereafter, the solutions, using foregoing steps, are cleaned with
water to perform a dynamic bearing according to the embodiment of
the invention. FIG. 11B is a fragmentary sectional view of the
bearing in FIG. 11A.
[0073] In this embodiment, the deposited layer formed by
electroplating is not limited by the depth and width of the
pressure-generating groove. Furthermore, the formation of the
deposited layer can be modified by adjusting electroplating
parameters, for example the electroplating duration, rate of
electroplating, electroplating plus current and electroplating
liquor additive. As a fragmentary sectional view of the bearing 1
shown in FIG. 12, a thickness of the deposited layer 50 is greater
than that of the photoresist 20. An arched top is formed,
decreasing the area of a surface contacting a shaft for reducing
friction between the deposited layer and the shaft. Additionally,
by supplying different current to the exposed surface of the inner
wall 10, the thickness of the deposited layer 50 can be changed as
desired, as a fragmentary sectional view of another bearing 1 shown
in FIG. 13.
Third Embodiment
[0074] According to a third embodiment of the invention, a method
for manufacturing the bearing is substantially similar to the
second embodiment. The formation of the deposited layer, according
to the third embodiment of the invention, differs only slightly
from the second embodiment. The similar steps, for example
modeling, exposing and developing, already described in the second
embodiment are not described again here. Note that the bearing 1 in
the third embodiment can be metal such as brass, or nonmetal such
as aluminum oxide ceramic.
[0075] FIGS. 14A and 14B, a diagrammatic view and a fragmentary
sectional view of the bearing 1 after developing, respectively. In
this embodiment, subsequent to the developing step, a wear
resistant material, for example nickel-cobalt (Ni--Co) alloy,
silicon carbon (SiC), tungsten carbide (WC), is deposited on the
photoresist 20 and the surface of the inner wall 10, which is not
covered by the photoresist 20 (also referred to as the surface of
the appeared portion of the inner wall 10), by sputtering to form
the deposited layer 60. In FIGS. 15A and 15B, the photoresist 20
and the wear resistant material deposited thereon are stripped by
lift-off, to form the pressure-generating groove 12 between the two
adjacent deposited layers 60, so as to perform a dynamic bearing
according to the third embodiment of the invention.
Fourth Embodiment
[0076] The process of forming the deposited layer of the fourth
embodiment of the invention differs only slightly from the second
embodiment. The similar steps to the second embodiment, for example
modeling, exposing and developing, may refer to FIGS. 7-9 and its
corresponding descriptions, and are not provided again here. Note
that the bearing in this embodiment can be metal such as aluminum
or alloys thereof.
[0077] Subsequent to the developing step, a chemical reaction
occurs between the surface of the inner wall 10, which is not
covered by the photoresist 20, with ambient reactant to form a
compound. In this embodiment, the bearing 10 comprising, for
example, aluminum or aluminum alloy, is dipped into oxalic acid
solvent. In FIGS. 16A and 16B, an anode oxidation treatment is
executed, the wear resistant material is then generated on the
surface of the inner wall 10, which is not covered by photoresist
20, to form the deposited layer 70 comprising aluminum oxide. The
photoresist 20, reminding on the surface of the inner wall 10, is
removed by a stripping agent, such as acetone, following by washing
with water and drying, to form the pressure-generating groove
between the two adjacent deposited layers 70. The dynamic bearing,
as shown in FIGS. 17A and 17B, according to the fourth embodiment
of the invention, is complete. Noted that, in this embodiment the
ambient reactant is liquid phase, but the ambient reactant can be
liquid or gas phase, have a capable of reaction with the surface of
the inner wall of the bearing.
Fifth Embodiment
[0078] FIG. 18 is a diagrammatic view illustrating steps for
manufacturing the bearing according to a fifth embodiment of the
invention, in which the baring is shown in cross sectional view. In
this embodiment, the bearing is preferably made of copper or alloys
thereof.
[0079] As shown in (a) of FIG. 18, the surface of inner wall of the
bearing 1 is coated by photoresist 20a by the same steps as the
first embodiment. Thus, the repeated descriptions are not provided.
In this embodiment, the photoresist 20a is a negative photoresist,
for example, comprising acrylic resin and propylene glycol
monomethyl ether acetate, or a negative photoresist comprising
epoxy resin and gamma butyrolactone.
[0080] As shown in (b) of FIG. 18, the lamp 30a capable of emitting
a wavelength in ultraviolet is placed inside the bearing 1 to
expose the photoresist 20a. In this embodiment, the lamp 30a has a
mask with a pressure-generating groove pattern thereon and has an
opaque area where the groove pattern located. In this embodiment,
the lamp 30a can be similar to the one shown in FIG. 7.
[0081] After exposing, the lamp 30a is removed. A portion of the
photoresist 20a without photosensitizing is cleaned by developer
and the portion of the inner wall made of copper is appeared, as
shown in (c) of FIG. 18.
[0082] Subsequently, as shown in (d) of FIG. 18, the portion of the
inner wall without covering the photoresist 20a, also referred to
as an appeared portion of the inner wall, is etched by an etchant
to form a desirable groove 12. Next, the photoresist 20a reminding
on the inner wall is stripped by a stripping agent to form a
desirable groove pattern 12.
[0083] The steps for manufacturing the bearing are substantially
the same as the first embodiment, unless the negative photoresist
is utilized in this embodiment. Thus, groove pattern of the mask on
the lamp in this embodiment is corresponding complement to that in
the first embodiment.
Sixth Embodiment
[0084] FIG. 19 is a diagrammatic view illustrating steps for
manufacturing the bearing according to a sixth embodiment of the
invention, in which the bearing is shown in cross sectional view.
In this embodiment, the bearing is preferably made of copper or
alloys thereof.
[0085] As shown in (a) of FIG. 19, the surface of inner wall of the
bearing 1 is coated by photoresist 20a by the similar steps to the
first embodiment. Thus, the repeated descriptions are not provided.
In this embodiment, the photoresist 20a is a negative
photoresist.
[0086] As shown in (b) of FIG. 19, the lamp 30 capable of emitting
a ultraviolet wavelength is placed inside the bearing 1 to expose
the photoresist 20a. In this embodiment, the lamp 30 has a mask
with a pressure-generating groove pattern thereon. The groove
pattern located on the lamp 30 is transparent. In this embodiment,
the lamp 30 can be the same as the one shown in FIG. 3.
[0087] After exposing, the lamp 30 is removed. A portion of the
photoresist 20a without photosensitizing is cleaned by a developer
and the portion of the inner wall made of copper is appeared, as
shown in (c) of FIG. 19.
[0088] As shown in (d) of FIG. 19, a deposited layer 80 is
deposited on the portion of the inner wall, which is not covered
with the photoresist 20a, also referred to as an appeared portion
of the inner wall. Next, the photoresist 20a is stripped by a
stripping agent and a desirable groove pattern 12a is formed
between the two adjacent deposited layers 80.
[0089] This embodiment is the same as the fifth embodiment, unless
the groove pattern of the mask on the lamp is transparent. The
desirable groove pattern is formed by deposited layers.
[0090] In the sixth embodiment, the deposited layer 80 is
preferably made of a wear resistant material and is formed by the
similar step to the second, third and fourth embodiments.
Seventh Embodiment
[0091] FIG. 20 is diagrammatic view illustrating steps for
manufacturing a shaft according to a seventh embodiment of the
invention, in which the shaft is shown in cross sectional view. In
this embodiment, the shaft is formed by cutting, turning or powder
sintering and is made of copper or alloys thereof.
[0092] As shown in (a) of FIG. 20, photoresist 20 is coated on the
surface of the shaft 2 by spray coating, dipping, spin coating or
centrifugal coating. Preferably, the photoresist 20 is made of a
positive photoresist.
[0093] As shown in (b) of FIG. 20, the shaft 2 is placed into a
circular lamp 90 capable of emitting ultraviolet wavelength to
expose the photoresist 20. A slice with a pressure-generating
groove pattern is attached to an inner surface of the circular lamp
90. Then, the exposing is executed to photosensitize the positive
photoresist corresponding to the transparent portion of the
slice.
[0094] In this embodiment, the slice is made of a mask 40 with the
pressure-generating groove pattern and an area thereof with the
pressure-generating groove pattern 401 located is transparent.
[0095] After exposing, the shaft is removed from the circular lamp
90. A portion of the photoresist 20 without photosensitizing is
cleaned by a developer and the surface of the shaft made of copper
is partly appeared, as shown in (c) of FIG. 20.
[0096] As shown in (d) of FIG. 20, the surface of the shaft without
covering the photoresist 20, also referred to as an appeared
surface of the shaft, is etched by an etchant. The photoresist 20
is then stripped by a stripping agent to form a desirable groove
pattern 12.
[0097] This embodiment is substantially the same as the first
embodiment, unless the groove is formed on the surface of the shaft
by photolithography and the circular lamp is utilized to expose the
surface of the shaft.
Eighth Embodiment
[0098] FIG. 21 is diagrammatic view illustrating steps for
manufacturing a shaft according to an eighth embodiment of the
invention, in which the shaft is shown in cross sectional view. In
this embodiment, the shaft is formed by cutting, turning or powder
sintering, and is made of copper or alloys thereof.
[0099] As shown in (a) of FIG. 21, the surface of the shaft 2 is
coated by photoresist 20 by the similar steps to the seventh
embodiment. Thus, the repeated descriptions are not provided here.
In this embodiment, the photoresist 20 is a positive
photoresist.
[0100] As shown in (b) of FIG. 21, the shaft 2 is placed into a
circular lamp (not shown) capable of emitting ultraviolet
wavelength to expose the photoresist 20. The exposing step in this
embodiment is the same as that in the seventh embodiment unless the
mask 40a with pressure-generating groove located is opaque.
[0101] After exposing, the shaft is removed from the circular lamp.
A portion of the photoresist 20 not photosensitized is cleaned by a
developer to appear the surface of the shaft made of copper and
form a groove pattern 401a corresponding to the groove pattern of
the mask 40a, as shown in (c) of FIG. 21.
[0102] As shown in (d) of FIG. 21, the deposited layer 80 is formed
on the surface of the shaft without covering the photoresist 20,
also referred to as an appeared surface of the shaft. The
photoresist 20 is then stripped by a stripping agent to form a
desirable groove pattern 12a between the two adjacent deposited
layers.
[0103] This embodiment is substantially the same as the seventh
embodiment unless the groove pattern of the mask on the lamp is
opaque. Thus, the desirable groove pattern is formed by the
deposited layer.
[0104] In this embodiment, the deposited layer 80 is preferably
made of wear resistant material and formed by the similar steps to
the second, the third and the fourth embodiments.
Ninth Embodiment
[0105] FIG. 22 is diagrammatic view illustrating steps for
manufacturing a shaft according to a ninth embodiment of the
invention, in which the shaft is shown in cross sectional view and
is preferably made of cooper or alloys thereof.
[0106] As shown in (a) of FIG. 22, the surface of the shaft 2 is
coated by photoresist 20a by spray coating, dipping, spin coating
or centrifugal coating. Preferably, the photoresist 20a is a
negative photoresist.
[0107] As shown in (b) of FIG. 22, the shaft 2 is placed into a
circular lamp (not shown) capable of emitting ultraviolet
wavelength to expose the photoresist 20a. The exposing step in this
embodiment is the same as that in the eighth embodiment and the
repeated descriptions are not provided here.
[0108] After exposing, the shaft is removed from the circular lamp.
A portion of the photoresist 20a not photosensitized is cleaned by
a developer to appear the surface of the shaft made of copper and
form a groove pattern 401a corresponding to the groove pattern of
the mask 40a, as shown in (c) of FIG. 22.
[0109] As shown in (d) FIG. 22, the surface of the shaft without
covering the photoresist 20a, also referred to as an appeared
surface of the shaft, is etched by an etchant. The photoresist 20a
is then stripped by a stripping agent to form a desirable groove
pattern 12.
[0110] This embodiment is substantially the same as the eighth
embodiment unless the photoresist is the negative photoresist.
Thus, the groove is formed on exterior surface of the shaft by
etching.
Tenth Embodiment
[0111] FIG. 23 is a diagrammatic view illustrating steps for
manufacturing a shaft according to a tenth embodiment of the
invention, in which the shaft is shown in cross sectional view and
is preferably made of cooper or alloys thereof.
[0112] As shown in (a) of FIG. 23, the surface of the shaft 2 is
coated by photoresist 20a. In this embodiment the photoresist 20a
is a negative photoresist.
[0113] As shown in (b) of FIG. 23, the shaft 2 is placed into a
circular lamp 90 capable of emitting ultraviolet wavelength to
expose the photoresist 20a. A slice with a pressure-generating
groove pattern is attached to an inner surface of the circular lamp
90. Then, the exposing is executed to photosensitive the negative
photoresist corresponding to the transparent portion of the slice.
In this embodiment, the slice is a mask 40 with pressure-generating
pattern and an area where the pressure-generating groove 401
located is transparent.
[0114] After exposing, the shaft is removed from the circular lamp
90. A portion of the photoresist 20a not photosensitized is cleaned
by a developer to appear the surface of the copper shaft and form a
groove pattern 401 corresponding to the groove pattern of the mask
40, as shown in (c) of FIG. 23.
[0115] As shown in (d) of FIG. 23, a deposited layer 80 is formed
on the surface of the shaft without covering the photoresist 20a,
also referred to as an appeared surface of the shaft. The
photoresist 20a is then stripped by a stripping agent to form a
desirable groove pattern 12a between the two adjacent deposited
layers 80.
[0116] 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. To 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.
* * * * *