U.S. patent application number 11/663910 was filed with the patent office on 2008-01-31 for sliding element and fluid machine.
Invention is credited to Manabu Asai, Shunji Kasai, Takuya Kinoshita, Norihiko Miki, Takeyoshi Okawa, Nobuaki Takeda.
Application Number | 20080025861 11/663910 |
Document ID | / |
Family ID | 36118827 |
Filed Date | 2008-01-31 |
United States Patent
Application |
20080025861 |
Kind Code |
A1 |
Okawa; Takeyoshi ; et
al. |
January 31, 2008 |
Sliding Element and Fluid Machine
Abstract
A lubrication part serving as a bearing metal is provided in a
scroll compressor at a sliding part between a cylindrical part of a
slide busing and an extension of a movable scroll. An inner
periphery of the lubrication part is formed so that its iron
substrate is given a surface roughness Ra of 3.7 .mu.m and a resin
layer containing FEP and PTFE is then provided on the roughened
substrate surface.
Inventors: |
Okawa; Takeyoshi; (Osaka,
JP) ; Takeda; Nobuaki; (Osaka, JP) ; Kasai;
Shunji; (Osaka, JP) ; Kinoshita; Takuya;
(Osaka, JP) ; Asai; Manabu; (Osaka, JP) ;
Miki; Norihiko; (Osaka, JP) |
Correspondence
Address: |
GLOBAL IP COUNSELORS, LLP
1233 20TH STREET, NW, SUITE 700
WASHINGTON
DC
20036-2680
US
|
Family ID: |
36118827 |
Appl. No.: |
11/663910 |
Filed: |
September 22, 2005 |
PCT Filed: |
September 22, 2005 |
PCT NO: |
PCT/JP05/17524 |
371 Date: |
March 27, 2007 |
Current U.S.
Class: |
418/178 |
Current CPC
Class: |
F16C 33/10 20130101;
C10M 2213/02 20130101; F04C 18/3562 20130101; C10M 111/04 20130101;
C10M 107/38 20130101; C10N 2040/02 20130101; F04C 23/008 20130101;
C10M 157/04 20130101; F04C 18/0215 20130101; C10M 2217/044
20130101; F04C 23/001 20130101; C10M 149/18 20130101; C10M 157/02
20130101; F16C 33/201 20130101; C10M 2213/0623 20130101; F16C
2360/42 20130101; C10M 2213/023 20130101; F05C 2225/04 20130101;
C10M 2213/062 20130101; F04C 29/0057 20130101; F04C 2230/91
20130101; C10M 147/02 20130101; C10M 2217/0443 20130101 |
Class at
Publication: |
418/178 |
International
Class: |
F04C 15/00 20060101
F04C015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2004 |
JP |
2004-281330 |
Mar 1, 2005 |
JP |
2005-056487 |
Claims
1. A sliding element comprising: a fluororesin-containing resin
layer on a surface of a metal substrate, the surface of the
substrate being subjected to surface roughening to have a surface
roughness larger than 0.5 .mu.m and smaller than 10 .mu.m in terms
of the arithmetic mean height Ra of the profile of the surface.
2. The sliding element of claim 1, wherein the surface of the
substrate is subjected to surface roughening to have a surface
roughness larger than 0.75 .mu.m and smaller than 10 .mu.m in terms
of the arithmetic mean height Ra of the profile of the surface.
3. The sliding element of claim 1, wherein the surface roughening
includes a conversion treatment.
4. The sliding element of claim 1, wherein the resin layer contains
polyamide-imide resin.
5. The sliding element of claim 1, wherein a surface layer of the
substrate is subjected to no hardening.
6. A fluid machine comprising: a sliding element including a
fluororesin-containing resin layer on at least part of a surface of
a metal substrate, the surface of the substrate under the resin
layer being subjected to surface roughening to have a surface
roughness larger than 0.5 .mu.m and smaller than 10 .mu.m in terms
of the arithmetic mean height Ra of the profile of the surface.
7. The fluid machine of claim 6, wherein the surface of the
substrate under the resin layer is subjected to surface roughening
to have a surface roughness larger than 0.75 .mu.m and smaller than
10 .mu.m in terms of the arithmetic mean height Ra of the profile
of the surface.
8. The fluid machine of claim 6, wherein the surface roughening
includes a conversion treatment.
9. The fluid machine of claim 6, wherein the resin layer contains
polyamide-imide resin.
10. The fluid machine of claim 6, wherein the sliding element is
exposed to refrigerant.
11. The fluid machine of claim 10, wherein the refrigerant contains
a fluorine-containing material.
12. The fluid machine of claim 10, wherein the mixture ratio of
lubricant to the refrigerant is 5% or less.
13. The fluid machine of claim 10, wherein substantially no
lubricant is mixed in the refrigerant.
14. The fluid machine of claim 6, further comprising a scroll
mechanism including a pair of scrolls meshing with each other, at
least one of the pair of scrolls constituting the sliding element,
and the scroll constituting the sliding element includes the resin
layer on at least part of a surface of a metal substrate.
15. The fluid machine of claim 14, wherein the scroll constituting
the sliding element is a movable scroll, and the resin layer is
directly formed on a bearing part of the movable scroll.
16. The fluid machine of claim 14, wherein the scroll constituting
the sliding element is a movable scroll, and the resin layer is
directly formed on the entire movable scroll.
17. The fluid machine of claim 14, wherein the scroll constituting
the sliding element is a movable scroll, and the resin layer is
directly formed on a movable wrap of the movable scroll.
18. The fluid machine of claim 14, wherein the scroll constituting
the sliding element is a fixed scroll, and the resin layer is
directly formed on an entire surface of the fixed scroll opposed to
the movable scroll.
19. The fluid machine of claim 6, further comprising a scroll
mechanism including a pair of scrolls meshing with each other, a
thrust bearing of a movable scroll of the pair of scrolls
constituting the sliding element, and the thrust bearing including
the resin layer directly formed on a sliding surface of the thrust
bearing on the movable scroll.
Description
TECHNICAL FIELD
[0001] This invention relates to sliding elements and fluid
compressor machines and particularly relates to a sliding element
including a fluorine-containing resin layer formed on a surface of
its metal substrate and a fluid machine using the sliding
element.
BACKGROUND ART
[0002] Almost all machines presently used employ sliding elements,
such as bearings or meshing gears. Such sliding elements are
required to have not only necessary mechanical strength but also
slidability or wear resistance in their surfaces. An example of a
method for satisfying the slidability or wear resistance is to
supply liquid lubricant to their sliding parts. However, depending
upon where the sliding element is used, the supply of liquid
lubricant may be unfavorable. In addition, the supply of liquid
lubricant often leads to cost rise. For these reasons, there have
been developed great many techniques for giving slidability or wear
resistance to the sliding element surface without using liquid
lubricant. An example of the techniques is a technique for forming
a sliding coating on a surface of the sliding element.
[0003] Since sliding elements are required to have mechanical
strength, their substrates are in many cases made of metal. Sliding
coatings commonly used for the substrates include solid lubricants,
such as MoS.sub.2 or graphite, and polymeric compounds, such as
fluororesin, because they have good sliding performance. However,
because such solid lubricants and polymeric compounds (resins) have
poor adhesion property to metal constituting the substrate, various
considerations have been made in order to enhance the adhesion
property.
[0004] Methods often considered as measures to enhance the adhesion
property are to roughen the substrate surface and apply solid
lubricant or resin to the roughened surface (see, for example,
Patent Document 1 and Patent Document 2). According to the methods,
the adhesion property is enhanced by penetrating solid lubricant or
resin into microscopic recesses in the substrate surface.
Patent Document 1: Published Japanese Patent Application No.
H05-180231
Patent Document 2: Published Japanese Patent Application No.
2000-145804
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0005] The technique disclosed in Patent Document 1 involves
hardening the surface layer of the metal substrate. Therefore, the
technique cannot be applied to sliding elements not involved in
such hardening.
[0006] According to a Barfield-type constant-velocity joint
disclosed in Patent Document 2, the substrate surface is subjected
to shot blasting to have a surface roughness of 10 to 30 .mu.m in
terms of center line average roughness Ra. Therefore, the surface
has only large concavities and convexities of simple profile, which
provides a small effect of penetrating solid lubricant or resin
into the concavities. This does not offer enhanced adhesion
property. Particularly, if resin is applied to the substrate
surface, a problem occurs that, during service, the resin may be
peeled off from the substrate, thereby significantly increasing the
coefficient of friction of the joint. This problem cannot be solved
even if the substrate surface after shot blasted to have a surface
roughness of 10 to 30 .mu.m in terms of center line average
roughness Ra is subjected to conversion treatment.
[0007] The present invention has been made in view of the foregoing
and, therefore, its object is to provide a sliding element in which
a fluororesin-containing sliding coating has an enhanced adhesion
property to the substrate surface and a fluid machine using the
same.
Means to Solve the Problems
[0008] To attain the above object, in the present invention, a
sliding element includes a fluororesin-containing resin layer on a
surface of its metal substrate.
[0009] Specifically, a first aspect of the invention is directed to
a sliding element including a fluororesin-containing resin layer on
a surface of a metal substrate. Furthermore, the surface of the
substrate is subjected to surface roughening to have a surface
roughness larger than 0.5 .mu.m and smaller than 10 .mu.m in terms
of the arithmetic mean height Ra of the profile of the surface.
[0010] According to the first aspect, the substrate surface and the
resin layer are firmly adhered to each other and there is almost no
possibility of the resin layer chipping off from the substrate.
[0011] A second aspect of the invention is the sliding element
according to the first aspect, wherein the surface of the substrate
is subjected to surface roughening to have a surface roughness
larger than 0.75 .mu.m and smaller than 10 .mu.m in terms of the
arithmetic mean height Ra of the profile of the surface.
[0012] According to the second aspect, the substrate surface and
the resin layer are very firmly adhered to each other and,
therefore, the chipping off of the resin layer from the substrate
can be surely prevented.
[0013] A third aspect of the invention is the sliding element
according to the first or second aspect, wherein the surface
roughening is conversion treatment.
[0014] According to the third aspect, the surface roughening can be
carried out with high accuracy and high reproducibility.
[0015] A fourth aspect of the invention is the sliding element
according to any one of the first to third aspects, wherein the
resin layer contains polyamide-imide resin.
[0016] According to the fourth aspect, the resin layer can be made
hard to break and can be more firmly adhered to the metal
substrate.
[0017] A fifth aspect of the invention is the sliding element
according to any one of the first to fourth aspects, wherein a
surface layer of the substrate is subjected to no hardening.
[0018] According to the aspect recited in claim 5, the need to
additionally carry out hardening is eliminated, thereby providing
cost reduction.
[0019] A sixth aspect of the invention is directed to a fluid
machine including a sliding element. Furthermore, the sliding
element includes a fluororesin-containing resin layer on at least
part of a surface of a metal substrate and the surface of the
substrate under the resin layer is subjected to surface roughening
to have a surface roughness larger than 0.5 .mu.m and smaller than
10 .mu.m in terms of the arithmetic mean height Ra of the profile
of the surface.
[0020] According to the sixth aspect, the substrate surface and the
resin layer of the sliding element in the fluid machine are firmly
adhered to each other and there is almost no possibility of the
resin layer chipping off from the substrate.
[0021] A seventh aspect of the invention is the fluid machine
according to the sixth aspect, wherein the surface of the substrate
under the resin layer is subjected to surface roughening to have a
surface roughness larger than 0.75 .mu.m and smaller than 10 .mu.m
in terms of the arithmetic mean height Ra of the profile of the
surface.
[0022] According to the seventh aspect, the substrate surface and
the resin layer are very firmly adhered to each other and,
therefore, the chipping off of the resin layer from the substrate
can be surely prevented.
[0023] An eighth aspect of the invention is the fluid machine
according to the sixth or seventh aspect, wherein the surface
roughening is conversion treatment.
[0024] According to the eighth aspect, the surface roughening can
be carried out with high accuracy and high reproducibility.
[0025] A ninth aspect of the invention is the fluid machine
according to any one of the sixth to eighth aspects, wherein the
resin layer contains polyamide-imide resin.
[0026] According to the ninth aspect, the resin layer can be made
hard to break and can be more firmly adhered to the metal
substrate.
[0027] A tenth aspect of the invention is the fluid machine
according to any one of the sixth to ninth aspects, wherein the
sliding element is exposed to refrigerant.
[0028] According to the tenth aspect, particularly the lubricating
property in refrigerant can be enhanced.
[0029] An eleventh aspect of the invention is the fluid machine
according to the tenth aspect, wherein the refrigerant contains a
fluorine-containing material.
[0030] According to the eleventh aspect, a compressor with high
cooling efficiency and excellent lubricating property can be
provided.
[0031] A twelfth aspect of the invention is the fluid machine
according to the tenth or eleventh aspect, wherein the mixture
ratio of lubricant to the refrigerant is 5% or less.
[0032] According to the twelfth aspect, since the mixture ratio of
lubricant to the refrigerant is small, the cooling efficiency can
be enhanced.
[0033] A thirteenth aspect of the invention is the fluid machine
according to the tenth or eleventh aspect, wherein substantially no
lubricant is mixed in the refrigerant.
[0034] According to the thirteenth aspect, the cooling efficiency
can be significantly enhanced.
[0035] A fourteenth aspect of the invention is the fluid machine
according to any one of the sixth to thirteenth aspects, further
comprising a scroll mechanism (40) including a pair of scrolls (50,
60) meshing with each other. Furthermore, at least one of the pair
of scrolls (50, 60) constitutes the sliding element. In addition,
the scroll (50, 60) serving as the sliding element includes the
resin layer on at least part of a surface of a metal substrate.
[0036] According to the fourteenth aspect, the resin layer formed
on at least one of the scrolls (50, 60) is firmly adhered to the
substrate and there is almost no possibility of the resin layer
chipping off from the substrate.
[0037] A fifteenth aspect of the invention is the fluid machine
according to the fourteenth aspect, wherein the resin layer is
directly formed on a bearing part (53) of the movable scroll
(50).
[0038] According to the fifteenth aspect, since the resin layer is
directly formed on the bearing part (53) of the movable scroll
(50), the bearing part (53) of the movable scroll (50) is firmly
adhered to the resin layer and the processing can be
simplified.
[0039] A sixteenth aspect of the invention is the fluid machine
according to the fourteenth aspect, wherein the resin layer is
directly formed on the entire movable scroll (50).
[0040] According to the sixteenth aspect, since the resin layer is
formed on the entire movable scroll (50), this facilitates the
processing.
[0041] A seventeenth aspect of the invention is the fluid machine
according to the fourteenth aspect, wherein the resin layer is
directly formed on a movable wrap (52) of the movable scroll
(50).
[0042] According to the seventeenth aspect, since the resin layer
is directly formed on the movable wrap (52) of the movable scroll
(50), the surface of the movable wrap (52) of the movable scroll
(50) is firmly adhered to the resin layer and the clearance between
the movable scroll (50) and the fixed scroll (60) can be
reduced.
[0043] An eighteenth aspect of the invention is the fluid machine
according to the fourteenth aspect, wherein the resin layer is
directly formed on an entire surface of the fixed scroll (60)
opposed to the movable scroll (50).
[0044] According to the eighteenth aspect, since the resin layer is
directly formed on the entire surface of the fixed scroll (60)
opposed to the movable scroll (50), the fixed scroll (60) is firmly
adhered to the resin layer and the clearance between the fixed
scroll (60) and the movable scroll (50) can be reduced.
[0045] A nineteenth aspect of the invention is the fluid machine
according to the sixth aspect, further comprising a scroll
mechanism (40) including a pair of scrolls (50, 60) meshing with
each other. Furthermore, a thrust bearing (80) of the movable
scroll (50) of the pair of scrolls (50, 60) constitutes the sliding
element. In addition, the thrust bearing (80) serving as the
sliding element includes the resin layer directly formed on a
sliding surface (81) thereof on the movable scroll (50).
[0046] According to the nineteenth aspect, since the resin layer is
directly formed on the sliding surface (81) of the thrust bearing
(80) on the movable scroll (50), the thrust bearing (80) and the
resin layer are firmly adhered to each other.
EFFECTS OF THE INVENTION
[0047] According to the first aspect, the adhesion property of the
resin layer to the metal substrate is enhanced, thereby providing
excellent slidability.
[0048] According to the second aspect, the adhesion property of the
resin layer to the metal substrate is surely enhanced, thereby
providing very excellent slidability.
[0049] According to the third aspect, the surface roughening of the
metal substrate can be carried out with high accuracy and high
reproducibility.
[0050] According to the fourth aspect, the resin layer can be
hardened and the adhesion property of the layer to the metal
substrate can be further enhanced.
[0051] According to the fifth aspect, cost reduction can be
achieved.
[0052] According to the sixth aspect, the sliding element in the
fluid machine exhibits high adhesion property of the resin layer to
the substrate surface and thereby providing excellent
slidability.
[0053] According to the seventh aspect, the sliding element in the
fluid machine exhibits surely exhibits high adhesion property of
the resin layer to the substrate surface and thereby providing very
excellent slidability.
[0054] According to the eighth aspect, the surface roughening of
the metal substrate of the sliding element in the fluid machine can
be carried out with high accuracy and high reproducibility.
[0055] According to the ninth aspect, the resin layer of the
sliding element in the fluid machine can be hardened and the
adhesion property of the layer to the metal substrate can be
further enhanced.
[0056] According to the tenth aspect, both the cooling efficiency
and the lubricating property can be enhanced.
[0057] According to the eleventh aspect, the lubricating property
and the compatibility of the sliding element with refrigerant can
be enhanced.
[0058] According to the twelfth aspect, the cooling efficiency can
be enhanced while the lubricating property is maintained.
[0059] According to the thirteenth aspect, the cooling efficiency
can be enhanced while the lubricating property is maintained.
[0060] According to the fourteenth aspect, the adhesion property of
the resin layer formed on at least one of the scrolls (50, 60) can
be enhanced, thereby providing excellent slidability.
[0061] According to the fifteenth aspect, the adhesion property of
the resin layer to the bearing part of the movable scroll (50) can
be enhanced, thereby providing further simplified processing.
[0062] According to the sixteenth aspect, the need is eliminated to
subject only a particular part of the movable scroll (50) to a
treatment for forming a resin layer, thereby facilitating the
processing.
[0063] According to the seventeenth aspect, the adhesion property
of the resin layer to the surface of the movable wrap (52) of the
movable scroll (50) can be enhanced and the clearance between the
movable scroll (50) and the fixed scroll (60) can be reduced,
thereby providing good sealing property.
[0064] According to the eighteenth aspect, the adhesion property of
the resin layer to the fixed scroll (60) can be enhanced and the
clearance between the movable scroll (50) and the fixed scroll (60)
can be reduced, thereby providing good sealing property.
[0065] According to the nineteenth aspect, the adhesion property of
the resin layer to the sliding surface (81) of the thrust bearing
(80) on the movable scroll can be enhanced, whereby the slidability
in the sliding surfaces of the movable scroll (50) and the thrust
bearing (80) can be enhanced.
BRIEF DESCRIPTION OF DRAWINGS
[0066] FIG. 1 is a cross-sectional view of a scroll compressor
according to Embodiment 1.
[0067] FIG. 2 is a schematic diagram illustrating a limit surface
pressure test.
[0068] FIG. 3 is a graph showing the relation between the surface
roughness Ra and the limit PV of a substrate.
[0069] FIG. 4 is a graph showing the results of a sliding test
carried out in refrigerant.
[0070] FIG. 5 is a graph showing the results of the limit surface
pressure test carried out in the air.
[0071] FIG. 6 is a graph showing the results of a wear amount test
carried out in the air.
[0072] FIG. 7 is a cross-sectional view of a scroll compressor
according to Embodiment 2.
[0073] FIG. 8 is a cross-sectional view of a swing compressor
according to Embodiment 3.
[0074] FIG. 9 is a horizontal cross-sectional view showing the
in-cylinder structure of the swing compressor according to
Embodiment 3.
[0075] FIG. 10 is a cross-sectional view of a swing compressor
according to Embodiment 4.
[0076] FIG. 11 is a cross-sectional view of a rotary compressor
according to Embodiment 5.
[0077] FIG. 12 is a horizontal cross-sectional view showing the
in-cylinder structure of the rotary compressor according to
Embodiment 5.
EXPLANATION OF REFERENCE NUMERALS
[0078] 50 movable scroll [0079] 52 movable wrap [0080] 53 extension
[0081] 60 fixed scroll [0082] 80 thrust bearing [0083] 81 top
surface of the thrust bearing
BEST MODE FOR CARRYING OUT THE INVENTION
[0084] Embodiments of the present invention will be described below
in detail with reference to the drawings.
Embodiment 1
[0085] A scroll compressor (10) according to this embodiment is a
fluid machine provided in a refrigerant circuit of a refrigeration
system and used to compress gas refrigerant that is a fluid.
[0086] <<Overall Structure of Scroll Compressor>
[0087] As shown in FIG. 1, the scroll compressor (10) is of
so-called fully enclosed type. The scroll compressor (10) includes
a casing (11) formed in the shape of a vertically elongated,
cylindrical, airtight container. The casing (11) contains a lower
bearing unit (30), an electric motor (35) and a compression
mechanism (40) as a scroll mechanism which are disposed thereinside
in order from bottom to top. Furthermore, the casing (11) is
internally provided with a vertically extending drive shaft
(20).
[0088] The interior of the casing (11) is partitioned from top to
bottom by a fixed scroll (60) of the compression mechanism (40).
Out of the interior spaces of the casing (11), one above the fixed
scroll (60) is configured as a first chamber (12) and the other
below the fixed scroll (60) is configured as a second chamber
(13).
[0089] A suction pipe (14) is mounted to the body of the casing
(11). The suction pipe (14) opens into the second chamber (13) in
the casing (11). A discharge pipe (15) is mounted to the upper end
of the casing (11). The discharge pipe (15) opens into the first
chamber (12) in the casing (11).
[0090] The drive shaft (20) has a main spindle (21), a flange (22)
and an eccentric part (23). The flange (22) is formed at the upper
end of the main spindle (21) and has the shape of a disc having a
larger diameter than the main spindle (21). The eccentric part (23)
extends from the top surface of the flange (22). The eccentric part
(23) has the shape of a round column having a smaller diameter than
the main spindle (21) and its axis is eccentric with respect to the
axis of the main spindle (21).
[0091] The main spindle (21) of the drive shaft (20) passes through
a frame member (41) of the compression mechanism (40). The main
spindle (21) is supported through a roller bearing (42) to the
frame member (41). The flange (22) and the eccentric part (23) of
the drive shaft (20) is located in the second chamber (13) above
the frame member (41).
[0092] A slide bush (25) is mounted to the drive shaft (20). The
slide bush (25) includes a cylindrical part (26) and a balance
weight (27) and is disposed on the flange (22). The eccentric part
(23) of the drive shaft (20) is inserted in the cylindrical part
(26) of the slide bush (25).
[0093] The lower bearing unit (30) is located within the second
chamber (13) in the casing (11). The lower bearing unit (30) is
fixed to the frame member (41) by a bolt (32). Furthermore, the
lower bearing unit (30) supports the main spindle (21) of the drive
shaft (20) through a ball bearing (31).
[0094] An oil pump (33) is mounted to the lower bearing unit (30).
The oil pump (33) engages with the lower end of the drive shaft
(20). The oil pump (33) is driven by the drive shaft (20) to suck
up refrigerator oil accumulating in the bottom of the casing (11).
The refrigerator oil sucked up by the oil pump (33) is fed through
a channel formed inside the drive shaft (20) as to the compression
mechanism (40).
[0095] The electric motor (35) includes a stator (36) and a rotor
(37). The stator (36) is fixed, together with the lower bearing
unit (30), to the frame member (41) by the bolt (32). The rotor
(37) is fixed to the main spindle (21) of the drive shaft (20).
[0096] A terminal (16) for power feed is mounted to the body of the
casing (11). The terminal (16) is covered with a terminal box (17).
The electric motor (35) is fed with electric power through the
terminal (16).
[0097] <<Structure of Compression Mechanism>>
[0098] The compression mechanism (40) includes the fixed scroll
(60) and a movable scroll (50) and also includes the frame member
(41) and an Oldham ring (43). The compression mechanism (40)
employs, for example, a so-called asymmetric scroll design.
[0099] The movable scroll (50) includes a movable plate (51), a
movable wrap (52) and an extension (53). The movable plate (51) is
formed in the shape of a thickish disc. The extension (53) is
integrally formed with the movable plate (51) to extend from the
bottom surface (back surface) of the movable plate (51). The
extension (53) is located substantially in the center of the
movable plate (51). The extension (53) receives the cylindrical
part (26) of the slide bush (25), thereby constituting a bearing
part. In other words, the eccentric part (23) of the drive shaft
(20) is inserted through the slide bush (25) in the movable scroll
(50).
[0100] The movable wrap (52) stands up from the top surface (front
surface) of the movable plate (51) and is integrally formed with
the movable plate (51). The movable wrap (52) is formed in the
shape of a spiral wall having a constant height.
[0101] The movable scroll (50) is disposed on the frame member (41)
with the Oldham ring (43) and a thrust bearing (80) interposed
therebetween. The Oldham ring (43) is formed with two pairs of
keys. One of the two pairs of keys of the Oldham ring (43) engage
with the movable plate (51) and the remaining pair of keys engage
with the frame member (41). The Oldham ring (43) restricts the
rotation of the movable scroll (50) on its axis. The Oldham ring
(43) can slide on the movable scroll (50) and the frame member
(41).
[0102] The thrust bearing (80) is disposed in a recess of the frame
member (41). The top surface of the thrust bearing (80) provides a
sliding surface on which the bottom surface of the movable plate
(51) of the movable scroll (50) slides. In other words, the movable
scroll (50) can move bodily around the drive shaft (20) while
sliding with the bottom surface of the movable plate (51) on the
top surface (81) of the thrust bearing (80).
[0103] As shown in FIG. 1, the fixed scroll (60) includes a fixed
plate (61), a fixed wrap (63) and a brim (62). The fixed plate (61)
is formed in the shape of a thickish disc. The diameter of the
fixed plate (61) is approximately equal to the inner diameter of
the casing (11). The brim (62) is formed in the shape of a wall
extending downward from the peripheral edge of the fixed plate
(61). The fixed scroll (60) is fixed to the frame member (41) by a
bolt (44), with the lower end of the brim (62) abutting on the
frame member (41). The fixed scroll (60) is in close contact at its
brim (62) with the casing (11), thereby partitioning the interior
of the casing (11) into the first chamber (12) and the second
chamber (13).
[0104] The fixed wrap (63) stands up from the bottom surface (front
surface) of the fixed plate (61) and is integrally formed with the
fixed plate (61). The fixed wrap (63) is formed in the shape of a
spiral wall having a constant height and has a length of
approximately three helical turns.
[0105] An inner wrap face (64) and an outer wrap face (65) of the
fixed wrap (63), which are both side faces thereof, slide
respectively on an outer wrap face (54) and an inner wrap face (55)
of the movable wrap (52), which are both side faces thereof. The
bottom surface (front surface) of the fixed plate (61), i.e., a
bottom land (66) thereof from which the fixed wrap (63) does not
extend, slides on the end face of the movable wrap (52). The top
surface (front surface) of the movable plate (51), i.e., a land
(56) thereof from which the movable wrap (52) does not extend,
slides on the end face of the fixed wrap (63). Furthermore, the
fixed plate (61) has a discharge port (67) formed in the vicinity
of the volute center of the fixed wrap (63). The discharge port
(67) passes through the fixed plate (61) and opens into the first
chamber (12).
[0106] As described above, the scroll compressor (10) of this
embodiment is disposed in the refrigerant circuit for a
refrigerator. The refrigerant circuit operates in a vapor
compression refrigeration cycle by circulating refrigerant
therethrough. During the operation, the scroll compressor (10)
sucks low-pressure gas refrigerant from an evaporator, compresses
it and feeds out high-pressure gas refrigerant obtained by
compression towards a condenser.
[0107] The refrigerant contains a fluorine-containing material. The
mixture ratio of lubricant to the refrigerant is 5% or less, or
alternatively substantially no lubricant is mixed in the
refrigerant.
[0108] When the scroll compressor (10) is driven, the cylindrical
part (26) of the slide bush (25) slides on the extension (53) of
the movable scroll (50). In this embodiment, the sliding part is
provided with a lubrication part (70) serving as a bearing metal.
The lubrication part (70) has a cylindrical form and constitutes a
sliding element in which its substrate is made of iron and a
lubricant layer (resin layer) is provided on a surface (the inner
surface) of the substrate. The inner surface of the lubrication
part (70) provided with the lubricant layer slides on the outer
surface of the cylindrical part (26) of the slide bush (25).
[0109] The substrate surface of the lubrication part (70) is first
subjected to conversion treatment to have a surface roughness Ra of
3.7 .mu.m. Then, a lubricant layer, which is a resin layer of
approximately 100 .mu.m thickness, is formed on the substrate
surface by applying on the substrate surface a lubricant obtained
by mixing polyamide-imide resin (hereinafter, referred to as PAI),
polytetrafluoroethylene (hereinafter, referred to as PTFE) and
polytetrafluoroethylene-hexafluoropropylene copolymer resin
(hereinafter, referred to as FEP) together. Note that here the
surface roughness Ra indicates the arithmetic mean height Ra of the
surface profile, as defined in JIS B0601-2001. Also in the
description below, the expression of "surface roughness Ra"
indicates the arithmetic mean height Ra defined in JIS.
[0110] The placement of the lubrication part (70) having the above
configuration enables the cylindrical part (26) of the slide bush
(25) and the lubrication part (70) to continue to slide together at
a low coefficient of friction for a very long time even while being
exposed to the refrigerant.
[0111] <<Evaluation of Sliding Part>>
[0112] Next, a description is given of studies made on the
lubrication part (70).
[0113] Fluorine-containing resins have low coefficient of friction
on metal and excellent slidability. However, as already described
in "Problems to Be Solved by the Invention", fluorine-containing
resins have poor adhesion property to the metal substrate and,
therefore, are readily peeled off from the metal substrate. The
Inventors conducted intensive studies on what surface roughness of
the substrate could improve the adhesion property of
fluorine-containing resin to the substrate.
[0114] The way of studies was carried out according to a limit
surface pressure test using a ring and a disc specimen as shown in
FIG. 2. The limit surface pressure test is a test for evaluating
the adhesion property of lubricant to the substrate, in which
evaluation is made by rotating the ring made of SUJ2 (according to
JIS G4805-1990) at a constant velocity and pressing the evaluation
specimen (disc) against the ring along the axis of rotation. In the
evaluation test, the load imposed on the ring by pressing was
increased stepwise at regular time intervals while the torque
against the ring was measured.
[0115] Then, the load when the torque abruptly increased was
converted to a surface pressure and the product of the surface
pressure and the rotational velocity was determined as a limit PV
(limit surface pressure-velocity product) that is an evaluation
index for adhesion property. Specifically, when the lubricant of
the specimen is peeled off from the substrate, the coefficient of
friction between the ring and the disc abruptly increases and the
torque abruptly increases. Therefore, the adhesion property can be
evaluated from the limit PV. As the limit PV increases, the
adhesion property becomes more excellent. Note that the above test
was made in the atmosphere without interposing any lubrication oil
between the ring and the disc.
[0116] Each specimen was prepared by roughening a surface of an
iron substrate by conversion treatment and then forming on the
surface a lubricant layer containing fluororesin. The surface
roughness Ra of the substrate was controlled by changing the
treatment conditions of the conversion treatment. In the above
test, manganese phosphate was used for the conversion treatment.
The lubricant layer was formed from a resin mixture having a
composition of PAI/FEP/PTFE=70/24/6. The lubricant layer was formed
into a thickness of approximately 100 .mu.m. After the application
of the resin mixture, the lubricant layer was sintered and its
surface was then polished.
[0117] FIG. 3 is a graph showing the relation between the surface
roughness Ra and the limit PV of the substrate. Note that
"Substrate Ra" shown in FIG. 3 indicates the arithmetic mean height
Ra of the profile in the substrate surface, as defined in JIS
B0601-2001.
[0118] As can be seen from the graph, if Ra is smaller than 0.5
.mu.m, the limit PV is less than 0.4 MPam/s. If Ra is over 0.5
.mu.m, the limit PV is larger than 0.4 MPam/s, which provides
sufficient adhesion property for the application to general sliding
elements. If the limit PV is not smaller than 1 MPam/s (i.e., Ra is
not smaller than 0.75 .mu.m), the substrate surface can hold
sufficient adhesion property even upon change of the environment,
which is preferable. Note that, for applications in which higher
adhesion property is needed, the limit PV is preferably not smaller
than 1.0 MPam/s (i.e., Ra is preferably not smaller than 0.75
.mu.m) and, more preferably, not smaller than 1.5 MPam/s (i.e., Ra
is more preferably not smaller than 0.85 .mu.m).
[0119] On the other hand, if the surface roughness Ra is too large,
the maximum height Rz in the roughened surface is increased.
Therefore, part of the substrate protrudes beyond the surface of
the lubricant layer. In addition, in order to increase the surface
roughness Ra, the conversion treatment must be carried out for a
long time, which raises the cost and easily breaks the concavities
and convexities of the substrate surface formed by the conversion
treatment. For these reasons, the surface roughness Ra is
preferably smaller than 10 .mu.m. More preferably, the surface
roughness Ra is not larger than 5 .mu.m because the lubricant layer
can be formed at low cost.
[0120] Next, a sliding performance evaluation test was made on
Sample B of this embodiment obtained by subjecting an iron
substrate to conversion treatment to have a surface roughness Ra of
3.7 .mu.m, applying a lubricant layer of the above composition to
the substrate surface, sintering the substrate and polishing the
substrate surface and Sample A formed for comparison. Sample A was
obtained by forming a porous bronze sintered compact (having a
surface roughness Ra of not smaller than 30 .mu.m) on an iron plate
and impregnating the iron plate with fluororesin. Note that
Comparative Sample A is a conventional sliding element used in
air-conditioning scroll compressors.
[0121] FIG. 5 shows the results of a limit surface pressure test
made in the air without using any lubrication oil. Comparative
Sample A seized at a surface pressure of approximately 5.5 MPa, but
Sample B did not seize even when the surface pressure reached 7 MPa
that is an upper limit for the tester.
[0122] FIG. 6 shows the results of a wear amount test made in the
air without using any lubrication oil. The test was carried out
under conditions that sliding was made at a surface pressure of 2.8
MPa and a sliding velocity of 1 m/s for an hour. Referring to the
graph, Comparative Sample A exhibited a wear amount of
approximately 45 .mu.m but Sample B exhibited a very small wear
amount of approximately 10 .mu.m. This shows that Sample B is
excellent in wear resistance.
[0123] FIG. 4 shows the results of a sliding test in refrigerant.
In air-conditioning compressors, generally, the refrigerant (HFC
refrigerant) and a lubrication oil are used in the form of a
mixture in a ratio of 65:35. In this test, however, data were
collected by changing the mixture ratio (concentration) of the
lubrication oil. The HFC refrigerant contains a fluorine-containing
material. In the sliding test results shown in FIG. 4, the wear
amounts of the specimen after sliding for two hours under the
conditions of a surface pressure of 3 MPa and a sliding velocity of
2 m/s are laid off as ordinates. The abscissa in the graph
indicates percentages of the lubrication oil mixed in the
refrigerant.
[0124] Comparative Sample A is a conventional element used in
sliding parts. Its wear amount was 13 .mu.m at a normal lubrication
oil concentration of 35% but increased to 24 .mu.m at a lubrication
oil concentration of 10%. For Sample B, its wear amount was 2 .mu.m
at a lubrication oil concentration of 10% and was very small, 4
.mu.m, even at a lubrication oil concentration of 0%, i.e., at a
refrigerant concentration of 100%. Therefore, the wear amount of
Sample B according to this embodiment at a refrigerant
concentration of 100% was smaller than that of Comparative Sample A
at a normal lubrication oil concentration (35%).
[0125] As is obvious from the above results, since Sample B
according to this embodiment hardly wears ever at a lubrication oil
concentration of 0%, there is no need to mix lubrication oil into
refrigerant, which significantly improves the cooling efficiency.
Since the fluororesin exists in the surface of the sliding element,
the surface is well fitted to refrigerant containing a
fluorine-containing material, which improves the sliding
performance. It can be considered that at the start or transition
of the compressor the sliding part is put under a completely dry
condition in which no refrigerant exists. Even in such a case,
Sample B according to this embodiment exhibits excellent sliding
performance. Such excellent sliding performance cannot be provided
unless the adhesion property of the fluorine-containing resin layer
(lubricant layer) to the substrate becomes high. In other words,
since the substrate surface of Sample B has an appropriate range of
surface roughnesses Ra, Sample B is very excellent in the adhesion
property of the fluorine-containing resin layer to the substrate.
Therefore, Sample B can exhibit an excellent sliding
performance.
[0126] Next, a description is given of the composition of the
fluororesin-containing resin layer.
[0127] The main component of the fluororesin-containing resin layer
is preferably composed of fluororesin of 15 mass % to 35 mass %
both inclusive and polyamide-imide resin of 65 mass % to 85 mass %
both inclusive. The fluororesin in the main component is preferably
composed of FEP and PTFE. In the fluororesin, the content of FEP is
preferably higher than that of PTFE. Specifically, the mass ratio
of FEP to PTFE in the fluororesin is preferably FEP:PTFE=7:3 to
99:1 and, more preferably, FEP to PTFE is 9 to 1.
[0128] If polyamide-imide resin is mixed into the resin layer in
the above manner, excellent impact resistance of polyamide-imide
resin can be utilized to form a high-impact resistance,
hard-to-peel resin coating on the sliding surface of the element.
Furthermore, since polyamide-imide resin also has a characteristic
of high hardness, the resin coating provides a comparatively hard
and hard-to-wear coating.
[0129] In addition to the main component composed of fluororesin
and polyamide-imide resin, the fluororesin-containing resin layer
may contain a pigment serving as a colorant, such as carbon, or
other additives. The amount of additives is selected to such a
value that does not adversely affect the performance of the
fluororesin-containing resin layer and the adhesion property
thereof to the substrate. For example, carbon as an additive should
be selected to not larger than 3% by mass of fluororesin,
preferably not larger than 1% by mass thereof and more preferably
not larger than 0.5% by mass thereof.
[0130] The thickness of the fluororesin-containing resin layer is
preferably 35 .mu.m to 120 .mu.m both inclusive. If the thickness
is smaller than 35 .mu.m, the sliding performance might be
deteriorated. If the thickness is larger than 120 .mu.m, the
production cost will be high. Therefore, in consideration of
aspects of the sliding performance and the cost, the thickness of
the resin layer is preferably 50 .mu.m to 105 .mu.m both inclusive.
Note that the reference to the thickness of the resin layer is made
as representative of the average thickness but the resin layer may
locally have thicknesses other than the above range.
[0131] According to this embodiment, since in the lubrication part
(70) serving as a sliding element a lubrication layer is provided
by giving the substrate a predetermined surface roughness Ra and
forming a fluororesin-containing resin layer on the roughened
surface, the substrate and the fluororesin-containing resin layer
are firmly adhered to each other, thereby exhibiting excellent
sliding performance. Particularly if the sliding element is used in
refrigerant containing a fluorine-containing material, it hardly
wears even without lubrication oil and can continue to slide at low
coefficient of friction for a long time. Furthermore, since the
sliding element of this embodiment exhibits excellent sliding
performance by subjecting the substrate surface to conversion
treatment to have a predetermined surface roughness Ra, it can be
easily produced at low cost. Furthermore, since the sliding element
of this embodiment can be produced by such a simple method, this
method provides not only production of the sliding part between the
cylindrical part (26) of the slide bush (25) and the extension (53)
of the movable scroll (50) but also production of sliding elements
of various types and applications.
[0132] --Modification 1 of Embodiment 1--
[0133] Although in Embodiment 1 the sliding element is provided as
the lubrication part (70) formed of a separate piece, a sliding
element in this modification is obtained by directly forming a
resin layer as a lubricant on the extension (53) of the movable
scroll (50).
[0134] Specifically, the inner periphery of the extension (53) of
the movable scroll (50) is roughened by conversion treatment so
that the substrate has a surface roughness Ra of 1 .mu.m, and a
resin layer having a composition of PAI/FEP/PTFE=70/25/5 is then
formed on the inner periphery.
[0135] According to this modification, since a resin layer is
directly formed on the extension (53) of the movable scroll (50)
that is a sliding element, the number of processing steps can be
reduced and the number of parts can also be reduced. The rest of
the configuration, the other operations and the other effects are
the same as in Embodiment 1.
[0136] --Modification 2 of Embodiment 1--
[0137] Although in Modification 1 a resin layer is formed on a
sliding part of the extension (53) of the movable scroll (50), a
resin layer in this modification is instead formed on the bottom
surface of the movable plate (51).
[0138] Specifically, the bottom surface of the movable plate (51)
of the movable scroll (50) in the scroll compressor (10) slides on
the top surfaces of the thrust bearing (80) and the Oldham ring
(43). Therefore, in this modification, the bottom surface of the
movable plate (51) is subjected to conversion treatment so that the
substrate has a surface roughness Ra of 1 .mu.m and a resin layer
having a composition of PAI/FEP/PTFE=70/25/5 is then formed on the
substrate surface.
[0139] According to this modification, since a resin layer is
directly formed on the movable plate (51) of the movable scroll
(50) that is a sliding element, the number of processing steps can
be reduced. The rest of the configuration, the other operations and
the other effects are the same as in Embodiment 1.
[0140] --Modification 3 of Embodiment 1--
[0141] Although in Modification 1 a resin layer is formed on the
inner periphery of the extension (53) of the movable scroll (50), a
resin layer in this modification is instead directly formed on the
movable wrap (52) of the movable scroll (50) that is a sliding
element.
[0142] Specifically, the side faces of the movable wrap (52) of the
movable scroll (50) in the scroll compressor (10) slide on the side
faces of the fixed wrap (63) of the fixed scroll (60). Furthermore,
the end face of the movable wrap (52) slides on the bottom land
(66) of the fixed plate (61) of the fixed scroll (60). Therefore,
in this modification, the surface of the movable wrap (52) is
subjected to conversion treatment so that the substrate has a
surface roughness Ra of 1 .mu.m and a resin layer having a
composition of PAI/FEP/PTFE=70/25/5 is then formed on the substrate
surface.
[0143] According to this modification, since a resin layer is
directly formed on the movable wrap (52) of the movable scroll
(50), the surface of the movable wrap (52) of the movable scroll
(50) is firmly adhered to the resin layer and its clearances to the
fixed wrap (63) of the fixed scroll (60) and the bottom land (66)
of the fixed plate (61) are reduced, thereby providing good sealing
property. The rest of the configuration, the other operations and
the other effects are the same as in Embodiment 1.
[0144] --Modification 4 of Embodiment 1--
[0145] Although in Modification 1 a resin layer is provided on the
inner periphery of the extension (53) of the movable scroll (50), a
resin layer in this modification is instead directly formed on the
whole of the movable scroll (50) that is a sliding element.
[0146] Specifically, in order to improve the slidability of the
inner periphery of the extension (53) of the movable scroll (50)
and the bottom surface of the movable plate (51) on their
counterparts in the scroll compressor (10) as described in
Modifications 1 and 2 of Embodiment 1 and in order to improve the
slidability and sealing property of the movable scroll (50) to the
opposed faces of the fixed scroll (60) as described in Modification
3, a resin layer is directly formed on the entire movable scroll
(50).
[0147] More specifically, the entire surface of the movable scroll
(50) is subjected to conversion treatment so that the substrate has
a surface roughness Ra of 1 .mu.m and a resin layer having a
composition of PAI/FEP/PTFE=70/25/5 is then formed on the substrate
surface.
[0148] According to this modification, there is no need to
partially subjecting the movable scroll (50) to a treatment for the
formation of a resin layer and the resin layer is directly formed
on the entire movable scroll (50). Therefore, the number of
processing steps can be reduced. The rest of the configuration, the
other operations and the other effects are the same as in
Embodiment 1.
[0149] --Modification 5 of Embodiment 1--
[0150] Although in Modification 1 a resin layer is provided on the
inner periphery of the extension (53) of the movable scroll (50), a
resin layer in this modification is instead directly formed on an
entire surface of the fixed scroll (60) opposed to the movable
scroll (50).
[0151] Specifically, a surface of the fixed scroll (60) opposed to
the movable scroll (50) in the scroll compressor (10), i.e., the
fixed wrap (63) of the fixed scroll (60) and the bottom land (66)
of the fixed plate (61), slides on the movable wrap (52) of the
movable scroll (50) and the top surface of the movable plate (51).
Therefore, in this modification, both side faces and the end face
of the fixed wrap (63) of the fixed scroll (60) and the bottom land
of the fixed plate (61) are subjected to conversion treatment so
that the substrate has a surface roughness Ra of 1 .mu.m and a
resin layer having a composition of PAI/FEP/PTFE=70/25/5 is then
formed on the substrate surface.
[0152] According to this modification, since a resin layer is
directly formed on the entire opposed surface of the fixed scroll
(60) to the movable scroll (50), the fixed scroll (60) is firmly
adhered to the resin layer and its clearance to the movable scroll
(50) is reduced, thereby providing good sealing property. The rest
of the configuration, the other operations and the other effects
are the same as in Embodiment 1.
[0153] --Modification 6 of Embodiment 1--
[0154] Although in Modification 1 a resin layer is provided on the
inner periphery of the extension (53) of the movable scroll (50), a
resin layer in this modification is instead directly formed on the
outer periphery of the cylindrical part (26) of the slide bush
(25).
[0155] Specifically, the outer periphery of the cylindrical part
(26) of the slide bush (25) in the scroll compressor (10) slides on
the inner periphery of the extension (53) of the movable scroll
(50). Therefore, in this modification, the outer periphery of the
cylindrical part (26) of the slide bush (25) is subjected to
conversion treatment so that the substrate has a surface roughness
Ra of 1 .mu.m and a resin layer having a composition of
PAI/FEP/PTFE=70/25/5 is then formed on the substrate surface.
[0156] According to this modification, since a resin layer is
directly formed on the outer periphery of the cylindrical part (26)
of the slide bush (25) that is a sliding element, the number of
processing steps can be reduced and the need is eliminated to
provide the lubrication part (70) like Modification 1 of Embodiment
1. The rest of the configuration, the other operations and the
other effects are the same as in Embodiment 1.
[0157] --Modification 7 of Embodiment 1--
[0158] Although in Modification 1 a resin layer is provided on the
inner periphery of the extension (53) of the movable scroll (50), a
resin layer in this modification is instead directly formed on the
top surface (81) of the thrust bearing (80).
[0159] Specifically, the top surface (81) of the thrust bearing
(80) in the scroll compressor (10) slides on the bottom surface of
the movable plate (51) of the movable scroll (50). Therefore, in
this modification, the top surface (81) of the thrust bearing (80)
is subjected to conversion treatment so that the substrate has a
surface roughness Ra of 1 .mu.m and a resin layer having a
composition of PAI/FEP/PTFE=70/25/5 is then formed on the substrate
surface.
[0160] According to this modification, since a resin layer is
directly formed on the top surface (81) of the thrust bearing (80),
the top surface (81) of the thrust bearing (80) and the resin layer
are firmly adhered to each other and the slidability can be
improved in the sliding part between the top surface (81) of the
thrust bearing (80) and the bottom surface of the movable plate
(51) of the movable scroll (50). The rest of the configuration, the
other operations and the other effects are the same as in
Embodiment 1.
[0161] --Modification 8 of Embodiment 1--
[0162] Although in Modification 1 a resin layer is provided on the
inner periphery of the extension (53) of the movable scroll (50), a
resin layer in this modification is instead directly formed on the
Oldham ring (43).
[0163] Specifically, one key of the Oldham ring (43) in the scroll
compressor (10) slides on the bottom surface of the movable plate
(51) of the movable scroll (50), while the body and the other key
of the Oldham ring (43) slide on the frame member (41). Therefore,
in this modification, the surfaces of the Oldham ring (43) are
subjected to conversion treatment so that the substrate has a
surface roughness Ra of 1 .mu.m and a resin layer having a
composition of PAI/FEP/PTFE=70/25/5 is then formed on the substrate
surfaces.
[0164] According to this modification, since a resin layer is
directly formed on the surfaces of the Oldham ring (43), the Oldham
ring (43) and the resin layer are firmly adhered to each other and
the slidability is improved in the sliding part between the one key
of the Oldham ring (43) and the bottom surface of the movable plate
(51) of the movable scroll (50) and the sliding part between the
body and the other key of the Oldham ring (43) and the frame member
(41). The rest of the configuration, the other operations and the
other effects are the same as in Embodiment 1.
Embodiment 2
[0165] A detailed description is given of Embodiment 2 of the
present invention with reference to FIG. 7.
[0166] In a scroll compressor (100) according to this embodiment,
instead of the drive shaft (20) in Embodiment 1 being supported
through the roller bearing (42) and the ball bearing (31) to the
frame member (41) and the lower bearing unit (30), the main spindle
(21) of the drive shaft (20) is supported through lubrication parts
(111, 121) serving as bearing metals to a main bearing part (110)
of the frame member (41) and a lower main bearing part (120) of a
lower bearing unit (119).
[0167] The lubrication parts (111, 121) are formed in the shape of
a cylinder and constitute sliding elements. Each lubrication part
(111, 121) is formed by subjecting the inner periphery of its
substrate made of iron to conversion treatment to have a surface
roughness Ra of 1 .mu.m and providing on the substrate inner
periphery a lubrication layer made of a resin layer having a
composition of PAI/FEP/PTFE=70/25/5.
[0168] When the scroll compressor (100) is driven, the main spindle
(21) of the drive shaft (20) slides through the lubrication parts
(111, 121) on the main bearing part (110) and the lower main
bearing part (120).
[0169] The placement of the lubrication parts (111, 121) having the
above configuration enables the main spindle (21) and the
lubrication parts (111, 121) to continue to slide together at low
coefficient of friction for a very long time. The rest of the
configuration, the other operations and the other effects are the
same as in Embodiment 1.
[0170] --Modification of Embodiment 2--
[0171] In Embodiment 2, the lubrication parts (111, 121) are
provided between the main spindle (21) and the main bearing part
(110) and between the main spindle (21) and the lower main bearing
part (120). Instead of this, in this embodiment, resin layers are
directly formed on the main bearing part (110) and the lower main
bearing part (120) or directly formed on the main spindle (21).
[0172] Specifically, either the inner peripheries of the main
bearing part (110) and the lower main bearing part (120) or
portions of the outer periphery of the main spindle (21)
corresponding to the sliding surfaces thereof on the main bearing
part (110) and the lower main bearing part (120) are subjected to
conversion treatment to have a substrate surface roughness Ra of 1
.mu.m and resin layers having a composition of PAI/FEP/PTFE=70/25/5
are then formed on the substrate surfaces.
[0173] Thus, the main bearing part (110) and the lower main bearing
part (120) constitute sliding elements having their respective
resin layers formed on their respective iron substrate surfaces or
the main spindle (21) constitutes a sliding element having resin
layers formed on surface portions of the iron substrate.
[0174] According to this modification, since resin layers are
directly formed either on the inner peripheries of the main bearing
part (110) and the lower main bearing part (120) or on portions of
the outer periphery of the main spindle (21), the number of
processing steps can be reduced and the number of parts can also be
reduced. The rest of the configuration, the other operations and
the other effects are the same as in Embodiment 2.
Embodiment 3
[0175] A detailed description is given of Embodiment 2 of the
present invention with reference to FIGS. 8 and 9.
[0176] A fluid machine according to this embodiment is a so-called
rolling piston type swing compressor (200). The swing compressor
(200) according to this embodiment, like those according to
Embodiments 1 and 2, is provided in a refrigerant circuit of a
refrigeration system and used to compress gas refrigerant that is a
fluid. The swing compressor (200) has a fully enclosed
configuration in which a compression mechanism (230) and an
electric motor (220) are contained in a domed casing (210).
[0177] The casing (210) includes a cylindrical body (211) and end
plates (212, 213) provided at the top and bottom of the body (211).
A lower part of the body (211) is provided with a suction pipe
(241). The upper end plate (212) is provided with a discharge pipe
(215) and a terminal (216) for feeding electric power to the
electric motor (220).
[0178] The compression mechanism (230) is disposed in a lower part
of the interior of the casing (210) and includes a cylinder (219)
and a rolling piston (228) contained in a cylinder chamber (225) of
the cylinder (219). The cylinder (219) is composed of a cylindrical
cylinder body (221) and a front head (222) and a rear head (223)
that close the top and bottom, respectively, of the cylinder body
(221). The cylinder chamber (225) is defined by the cylinder body
(221), the front head (222) and the rear head (223).
[0179] The electric motor (220) includes a stator (231) and a rotor
(232). The stator (231) is located above the compression mechanism
(230) and fixed to the body (211) of the casing (210) and the rotor
(232) is connected to the drive shaft (233).
[0180] The drive shaft (233) vertically passes through the cylinder
chamber (225). The front head (222) and the rear head (223) are
formed with a main bearing part (222a) and a sub bearing part
(223a), respectively, for the purpose of supporting the drive shaft
(233). The drive shaft (233) has an oil pump (236) provided at the
lower end thereof. The oil pump (236) allows oil accumulating in
the bottom of the casing (210) to flow through an oil feed pipe
(not shown) and feeds the oil as to the cylinder chamber (225) of
the compression mechanism (230).
[0181] The drive shaft (233) has an eccentric part (233a) formed in
the center of the cylinder chamber (225). The eccentric part (233a)
has a larger diameter than the drive shaft (233).
[0182] As shown in FIG. 9, the rolling piston (228) includes a
piston body (228a) and a blade (228c) integrally formed with the
piston body (228) and serving as a partition extending from the
piston body (228a). The inner periphery of the piston body (228a)
engages the eccentric part (233a) inserted in the piston body
(228a).
[0183] The cylinder body (221) is formed with a bush hole (221b).
The bush hole (221b) contains a pair of bushes (251, 252) of
approximately semi-circular cross section inserted therein. Opposed
flat faces of the pair of bushes (251, 252) define a blade groove
(229). The blade (228c) is inserted in the blade groove (229). The
pair of bushes (251, 252) are configured so that the blade (228c)
can move backward and forward in the blade groove (229) in
sandwiched relation between the pair of bushes (251, 252).
Concurrently, the bushes (251, 252) is configured to oscillate
together with the blade (228c) in the bush hole (221b).
[0184] Furthermore, the cylinder body (221) has a bush back chamber
(250) formed outwardly of the bush hole (221b) to accommodate the
distal end of the blade (228c).
[0185] When the drive shaft (233) rotates with the above
configuration, the rolling piston (228) rolls about a point on the
blade (228c) moving backward and forward in the blade groove (229).
This rolling provides not rotation of the piston body (228a) on its
axis, but bodily movement thereof around the inner periphery of the
cylinder chamber (225). Note that, during the bodily movement of
the piston body (228a), such a slight clearance that can form a
thin oil film is created at the contact point (260) between the
piston body (228a) and the inner periphery of the cylinder chamber
(225).
[0186] The blade (228c) partitions the cylinder chamber (225) into
a suction side space (225a) and a compression side space (225b).
The cylinder body (221) is formed with a suction port (214)
communicated with the suction side space (225a). The suction port
(214) is connected to the suction pipe (241). The front head (222)
is formed with a discharge port (242). The inner periphery of the
cylinder body (221) is formed with a discharge channel (243)
communicated with the discharge port (242). The top surface of the
front head (222) is formed with a recess (245). The recess (245) is
provided with a discharge valve (246) for selectively opening and
closing the discharge port (215).
[0187] When the swing compressor (200) as described above is
driven, the drive shaft (233) slides on the main bearing part
(222a) and the sub bearing part (223a) and the eccentric part
(233a) of the drive shaft (233) slides on the piston body (228a).
In this embodiment, these sliding parts are provided with
lubrication parts (222b, 223b, 228b) serving as bearing metals. The
lubrication parts (222b, 223b, 228b) are configured as in
Embodiment 1 and formed in the shape of a cylinder. The lubrication
parts (222b, 223b, 228b) are sliding elements each formed by
subjecting the inner periphery of its substrate made of iron to
conversion treatment to have a surface roughness of 1 .mu.m and
providing on the substrate inner periphery a lubrication layer made
of a resin layer having a composition of PAI/FEP/PTFE=70/25/5.
[0188] The placement of the lubrication parts (222b, 223b, 228b)
having the above configuration enables the drives shaft (233) and
the eccentric part (233a) of the drive shaft (233) to continue to
slide on the lubrication parts (222b, 223b) and the lubrication
part (228b), respectively, at low coefficient of friction for a
very long time.
[0189] --Modification 1 of Embodiment 3--
[0190] Although in Embodiment 3 the sliding elements are provided
as the lubrication parts (222b, 223b, 228b) formed of separate
pieces for the main bearing part (222a), the sub bearing part
(223a) and the eccentric part (233a) of the drive shaft (233),
sliding elements in this modification are instead obtained either
by directly forming resin layers as lubricants on portions of the
outer periphery of the drive shaft (233) sliding on the main
bearing part (222a) and the sub bearing part (223a) and the outer
periphery of the eccentric part (233a) or by directly forming resin
layers as lubricants on the inner peripheries of the main bearing
part (222a) and the sub bearing part (223a) and the inner periphery
of the piston body (228a).
[0191] Specifically, either the portions of the outer periphery of
the drive shaft (233) sliding on the main bearing part (222a) and
the sub bearing part (223a) and the outer periphery of the
eccentric part (233a) or the inner peripheries of the main bearing
part (222a), the sub bearing part (223a) and the piston body (228a)
are roughened by conversion treatment to have a substrate surface
roughness Ra of 1 .mu.m and lubrication layers made of resin layers
having a composition of PAI/FEP/PTFE=70/25/5 are then formed on the
substrate surfaces.
[0192] According to this modification, since not the lubrication
parts (222b, 223b, 228b) as described in Embodiment 3 are provided
but resin layers are directly formed either on the drive shaft
(233) and the eccentric part (233) or on the main bearing part
(222a), the sub bearing part (223a) and the piston body (228a), the
number of processing steps can be reduced and the number of parts
can also be reduced. The rest of the configuration, the other
operations and the other effects are the same as in Embodiment
3.
[0193] --Modification 2 of Embodiment 3--
[0194] Although in Embodiment 3 the sliding elements are provided
as the lubrication parts (222b, 223b, 228b) formed of separate
pieces for the main bearing part (222a), the sub bearing part
(223a) and the eccentric part (233a) of the drive shaft (233),
sliding elements in this modification are instead obtained by
directly forming resin layers on the entire bushes (251, 252).
[0195] Specifically, for the above bushes (251, 252), their opposed
faces defining the blade groove (229) slide on the blade (228c) and
the semi-circular faces of the bushes (251, 252) slide on the
surface of the bush hole (221b). Therefore, in this modification,
the entire surfaces of the bushes (251, 252) are subjected to
conversion treatment to have a substrate surface roughness Ra of 1
.mu.m and lubrication layers made of resin layers having a
composition of PAI/FEP/PTFE=70/25/5 are then formed on the
substrate surfaces.
[0196] According to this modification, since resin layers are
directly formed on the bushes (251, 252), the bushes (251, 252) are
firmly adhered to their associated resin layers and the slidability
of the blade groove (229) on the blade (228c) and the slidability
of the semi-circular faces of the bushes (251, 252) on the bush
hole (221b) are improved. This provides smooth forward and backward
movement of the blade (228c) in the blade groove (229) and in turn
enhances the reliability of bodily movement of the piston (228).
The rest of the configuration, the other operations and the other
effects are the same as in Embodiment 3.
[0197] --Modification 3 of Embodiment 3--
[0198] In Modification 1 of Embodiment 3, a resin layer is formed
on the outer periphery of the eccentric part (233a) of the drive
shaft (233) of the swing compressor (200). In this modification,
resin layers are instead formed on the top and bottom surfaces of
the eccentric part (233a).
[0199] Specifically, the top surface of the eccentric part (233a)
slides on the bottom surface of the front head (222) and the bottom
surface thereof slides on the top surface of the rear head (223).
Therefore, in this modification, the top and bottom surfaces of the
eccentric part (233a) are subjected to conversion treatment to have
a substrate surface roughness Ra of 1 .mu.m and lubrication layers
made of resin layers having a composition of PAI/FEP/PTFE=70/25/5
are then formed on the substrate surfaces.
[0200] According to this modification, since resin layers are
directly formed on the eccentric part (233a), the eccentric part
(233a) is firmly adhered to the resin layers and the clearance
between the eccentric part (233a) and each of the front head (222)
and the rear head (223) in the cylinder chamber (225) is reduced,
thereby providing good sealing property. This enhances the
reliability of this machine as a compressor. The rest of the
configuration, the other operations and the other effects are the
same as in Modification 1 of Embodiment 3.
[0201] If a resin layer is directly formed on the entire eccentric
part (233a), not only the above effects can be obtained but also
the slidability between the eccentric part (233a) and the piston
body (228a) can be improved like Modification 1 of Embodiment 3. In
addition, since there is no need to subject a plurality of portions
of the eccentric part (233a) individually to a treatment for
forming a resin layer, the processing can be simplified.
[0202] --Modification 4 of Embodiment 3--
[0203] In Modification 1 of Embodiment 3, a resin layer serving as
a lubrication layer is formed on the inner periphery of the piston
body (228a). In this modification, a resin layer is instead formed
on the whole of the rolling piston (228).
[0204] Specifically, the top surface of the rolling piston (228)
slides on the bottom surface of the front head (222), the bottom
surface thereof slides on the top surface of the rear head (223),
the outer periphery of the piston body (228a) slides on the inner
periphery of the cylinder body (221), the inner periphery of the
piston body (228a) slides on the eccentric part (233a), and the
side faces of the blade (228c) slide on the opposed faces of the
bushes (251, 252). Therefore, in this modification, the entire
surface of the piston (228) is subjected to conversion treatment so
that its substrate has a surface roughness Ra of 1 .mu.m and a
lubrication layer made of a resin layer having a composition of
PAI/FEP/PTFE=70/25/5 is then formed on the entire substrate.
[0205] According to this modification, since a resin layer is
directly formed on the entire rolling piston (228), there is no
need to subject a plurality of portions of the rolling piston (228)
individually to a treatment for forming a resin layer, thereby
simplifying the processing. Furthermore, the slidability between
the blade (228c) and the bushes (252, 252) can be improved, which
provides smooth forward and backward movement of the blade (228c)
and in turn provides accurate bodily movement of the piston body
(228a). Furthermore, the clearance between the rolling piston (228)
and the inner periphery of the cylinder chamber (225) can be
reduced, thereby providing good sealing property. This enhances the
reliability of this machine as a compressor. The rest of the
configuration, the other operations and the other effects are the
same as Embodiment 3.
[0206] --Modification 5 of Embodiment 3--
[0207] In Modification 3 of Embodiment 3, resin layers are formed
as lubricants on the eccentric part (233a) and the piston (228a).
In this modification, resin layers are instead directly formed on
the bottom surface of the front head (222), the top surface of the
rear head (223) and the inner periphery of the cylinder body
(221).
[0208] Specifically, the bottom surface of the front head (222)
slides on the top surface of the eccentric part (233a) and the top
surface of the piston body (228a), the top surface of the rear head
(223) slides on the bottom surface of the eccentric part (233a) and
the bottom surface of the piston body (228a), the inner periphery
of the cylinder body (221) slides on the outer periphery of the
piston body (228a). Therefore, in this modification, the bottom
surface of the front head (222), the top surface of the rear head
(223) and the inner periphery of the cylinder body (221) are
subjected to conversion treatment to have a substrate surface
roughness Ra of 1 .mu.m and lubrication layers made of resin layers
having a composition of PAI/FEP/PTFE=70/25/5 are then formed on the
substrate surfaces.
[0209] According to this modification, since resin layers are
directly formed on the bottom surface of the front head (222), the
top surface of the rear head (223) and the inner periphery of the
cylinder body (221), the resin layers are firmly adhered to the
front head (222), the rear head (223) and the cylinder body (221).
Furthermore, since resin layers are formed on the bottom surface of
the front head (222), the top surface of the rear head (223) and
the inner periphery of the cylinder body (221) that constitute the
inside wall surface of the cylinder chamber (225), the clearances
of the inside wall surface of the cylinder chamber (225) to the top
and bottom surfaces of the eccentric part (233a) and the top and
bottom surfaces and the outer periphery of the piston body (228a)
that slide on the inside wall surface of the cylinder chamber (225)
can be reduced, thereby providing good sealing property. This
enhances the reliability of this machine as a compressor. The rest
of the configuration, the other operations and the other effects
are the same as Embodiment 3.
Embodiment 4
[0210] A fluid machine according to Embodiment 4 of the present
invention is a swing compressor (300) as shown in FIG. 10. Although
the compression mechanism (230) in Embodiment 3 includes a single
cylinder (219), a compression mechanism (301) in this embodiment
includes a plurality of cylinder bodies (325, 326). The rest of the
configuration and the other operations are the same as in the swing
compressor (200) according to Embodiment 3.
[0211] The swing compressor (300) according to this embodiment,
like Embodiment 3, is provided in a refrigerant circuit of a
refrigeration system and used to compress gas refrigerant that is a
fluid. A description is given here only of the compression
mechanism (301) including a plurality of cylinder bodies (325,
326).
[0212] The compression mechanism (301) includes two cylinder bodies
(325, 326) and the two cylinder bodies (325, 326) are juxtaposed in
a direction of extension of a drive shaft (314), i.e., in a
vertical direction.
[0213] A front head (307) is disposed on top of the first cylinder
body (325) placed upwardly of the second cylinder body (326). A
rear head (308) is disposed on the underside of the second cylinder
body (326) downwardly of the first cylinder body (325). A middle
plate (327) is disposed as a partition plate between the first
cylinder body (325) and the second cylinder body (326). The middle
plate (327) is formed at the center with a through hole (327a)
through which the drive shaft (314) passes.
[0214] The front head (307), the first cylinder body (325), the
middle plate (327), the second cylinder body (326) and the rear
head (308) are arranged in this order and fastened together by
bolts. The drive shaft (314) passes through both the heads (307,
308), both the cylinder bodies (325, 326) and the middle plate
(327).
[0215] The first cylinder body (325) contains a first rolling
piston (333) disposed therein. The second cylinder body (326)
contains a second rolling piston (334) disposed therein.
Furthermore, in this embodiment, two compression chambers are
formed: a first compression chamber (335) defined by the front head
(307), the first cylinder body (325), the first piston (333) and
the middle plate (327) and a second compression chamber (336)
defined by the rear head (308), the second cylinder body (326), the
second piston (334) and the middle plate (327).
[0216] When the swing compressor (300) is driven, the top surface
of the middle plate (327) slides on the bottom surface of the first
rolling piston (333) and the bottom surface of the middle plate
(327) slides on the top surface of the second rolling piston (334).
Therefore, in this embodiment, the top and bottom surfaces of the
middle plate (327) are subjected to conversion treatment to have a
substrate surface roughness Ra of 1 .mu.m and resin layers having a
composition of PAI/FEP/PTFE=70/25/5 are then directly formed on the
substrate surfaces.
[0217] According to this embodiment, since resin layers are
directly formed on the middle plate (327), the middle plate (327)
is firmly adhered to the resin layers. Furthermore, the clearance
between the sliding surfaces formed of the top surface of the
middle plate (327) and the bottom surface of the first rolling
piston (333) and the clearance between the sliding surfaces formed
of the bottom surface of the middle plate (327) and the top surface
of the second rolling piston (334) can be reduced, thereby
providing good sealing property. This enhances the reliability of
this machine as a compressor. The rest of the configuration, the
other operations and the other effects are the same as Embodiment
3.
[0218] --Modification of Embodiment 4--
[0219] In Embodiment 4, resin layers are formed as lubricants on
the top and bottom surfaces of the middle plate (327). In this
modification, resin layers are instead directly formed on the
entire first rolling piston (333) and the entire second rolling
piston (334).
[0220] Specifically, the entire surfaces of the first rolling
piston (333) and the second rolling piston (334) are subjected to
conversion treatment so that their substrates have a surface
roughness Ra of 1 .mu.m and resin layers having a composition of
PAI/FEP/PTFE=70/25/5 are then formed on the substrate surfaces.
[0221] According to this modification, since resin layers are
directly formed on the first rolling piston (333) and the second
rolling piston (334), the first rolling piston (333) and the second
rolling piston (334) are firmly adhered to their respective resin
layers. Furthermore, like Embodiment 4, the clearance between the
bottom surface of the first rolling piston (333) and the top
surface of the middle plate (327) and the clearance between the top
surface of the second rolling piston (334) and the bottom surface
of the middle plate (327) can be reduced, thereby providing good
sealing property. This enhances the reliability of this machine as
a compressor. The rest of the configuration, the other operations
and the other effects are the same as Embodiment 4.
Embodiment 5
[0222] A fluid machine according to this embodiment is a rotary
piston type rotary compressor (400) as shown in FIGS. 11 and
12.
[0223] The rotary compressor (400) has substantially the same
configuration as the swing compressor (200) according to Embodiment
3 and, specifically, includes a compression mechanism (420) and an
electric motor (430) contained in a fully enclosed casing (410) and
has a discharge pipe (415) and a suction pipe (414) mounted to the
casing (410). As shown in FIG. 12, the rotary compressor (400) has
a configuration in which a rotary piston (424) and a blade (426) of
the compression mechanism (420) are separately provided and the
rotary piston (424) bodily moves around the inner periphery of the
cylinder chamber (425) while rotating itself on its axis.
[0224] Furthermore, the rotary compressor (400), like Embodiment 1,
is provided in a refrigerant circuit of a refrigeration system and
used to compress gas refrigerant that is a fluid. A description is
given here only of different constructional points of the rotary
compressor (400) according to this embodiment from the swing
compressor (200) according to Embodiment 3, i.e., only of the
compression mechanism (420).
[0225] The compression mechanism (420) includes a cylinder body
(421), a front head (422) and a rear head (423) and has a cylinder
chamber (425) defined by the cylinder body (421), the front head
(422) and the rear head (423).
[0226] The front head (422) and the rear head (423) are formed with
a main bearing part (422a) and a sub bearing part (423a),
respectively, both for supporting a drive shaft (433). An eccentric
part (433a) of the drive shaft (433) located inside the cylinder
chamber (425) is formed to have a larger diameter than a main body
(433b) of the drive shaft (433). The eccentric part (433a) is
inserted in the rotary piston (424) of the compression mechanism
(420). The rotary piston (424) is formed in the shape of a ring and
configured so that its outer periphery can contact the inner
periphery of the cylinder (421) substantially at a single
point.
[0227] The cylinder (421) is formed with a blade groove (421a)
along a radial direction of the cylinder (421). Fitted in the blade
groove (421a) is the blade (426) in sliding contact with the
cylinder (421). The blade (426) is urged inwardly in the radial
direction by a spring (427) seated in the blade groove (421a) and
its distal end is always in contact with the outer periphery of the
rotary piston (424).
[0228] The blade (426) partitions the cylinder chamber (425)
between the inner periphery of the cylinder (421) and the outer
periphery of the rotary piston (424) into a suction chamber (425a)
and a compression chamber (425b). The cylinder (421) is formed with
a suction port (428) that communicates the suction pipe (414) with
the suction chamber (425a). Furthermore, the cylinder (421) is
formed with a discharge port (429) that communicates the
compression chamber (425b) with the interior space of the casing
(410).
[0229] The top surface of the front head (422) is formed with a
recess (440). The recess (440) is provided with a discharge valve
(441) for selectively opening and closing the discharge port
(429).
[0230] When the swing compressor (200) as described above is
driven, the outer periphery of the rotary piston (421) slides on
the inner periphery of the cylinder (421), the top surface of the
rotary piston (424) slides on the bottom surface of the front head
(422) and the bottom surface of the rotary piston (424) slides on
the top surface of the rear head (423). Therefore, in this
embodiment, the entire surface of the rotary piston (424) is
subjected to conversion treatment so that its substrate has a
surface roughness Ra of 1 .mu.m and a resin layer having a
composition of PAI/FEP/PTFE=70/25/5 is then directly formed on the
entire substrate.
[0231] Since, thus, a resin layer is directly formed on the entire
rotary piston (424), the rotary piston (424) and the resin layer
are firmly adhered to each other. Furthermore, the slidability of
the rotary piston (424) on each of the front head (422) and the
rear head (423) can be improved and the clearance between the
sliding surfaces can be reduced, thereby providing good sealing
property of the cylinder chamber (425).
[0232] Also in this embodiment, the sliding parts as in Embodiment
3 and Modifications 1 to 5 of Embodiment 3 may be provided with
resin layers serving as lubrication layers.
[0233] Specifically, the drive shaft (433) slides on the main
bearing part (422a) and the sub bearing part (423a) and the
eccentric part (433a) slides on the piston (424). Therefore, these
sliding parts may be provided with lubrication parts (422b, 423b,
433b) serving as bearing metals. The lubrication parts (422b, 423b,
433b) are sliding elements having a cylindrical shape and obtained
by subjecting the peripheries of their substrates made of iron to
conversion treatment to have a surface roughness Ra of 1 .mu.m and
forming on the substrate surfaces lubrication layers made of resin
layers having a composition of PAI/FEP/PTFE=70/25/5. The provision
of the lubrication parts (422b, 423b, 433b) improves the
slidability in the sliding part between the drive shaft (433) and
the main bearing part (422a) and the sliding part between the drive
shaft (433) and the sub bearing part (423a) and the sliding part
between the eccentric part (433a) and the piston (424).
[0234] Alternatively, instead of provision of the lubrication parts
(422b, 423b, 433b), either portions of the outer periphery of the
drive shaft (433) sliding on the main bearing part (422a) and the
sub bearing part (423a) and the outer periphery of the eccentric
part (433a) or the inner peripheries of the main bearing part
(422a) and the sub bearing part (423a) and the inner periphery of
the piston (424) may be subjected to conversion treatment to have a
substrate surface roughness Ra of 1 .mu.m and lubrication layers
made of resin layers having a composition of PAI/FEP/PTFE=70/25/5
may be then formed on the substrate surfaces. This improves,
without provision of the lubrication parts (422b, 423b, 433b), the
slidability in the sliding part between the drive shaft (433) and
the main bearing part (422a) and the sliding part between the drive
shaft (433) and the sub bearing part (423a) and the sliding part
between the eccentric part (433a) and the piston (424).
[0235] Furthermore, since the blade (426) slides on the blade
groove (421a), either the surface of the blade (426) or the surface
of the blade groove (421a) may be subjected to conversion treatment
so that the substrate has a surface roughness Ra of 1 .mu.m and a
lubrication layer made of a resin layer having a composition of
PAI/FEP/PTFE=70/25/5 may be then formed on the substrate surface.
This provides smooth forward and backward movement of the blade
(426) in the blade groove (421a) and in turn provides smooth bodily
movement of the piston (424) accompanied by its rotation on its
axis. Thus, the reliability of this machine as a compressor can be
enhanced.
[0236] Furthermore, since the top surface of the eccentric part
(433a) slides on the bottom surface of the front head (422) and the
bottom surface of the eccentric part (433a) slides on the top
surface of the rear head (423), the top and bottom surfaces of the
eccentric part (433a) may be subjected to conversion treatment to
have a substrate surface roughness Ra of 1 .mu.m and lubrication
layers made of resin layers having a composition of
PAI/FEP/PTFE=70/25/5 may be then formed on the substrate surfaces.
Thus, the slidability of the surfaces of the eccentric part (433a)
sliding on the front head (422) and the rear head (423) can be
improved. In addition, the clearances in the sliding parts can be
reduced, thereby good sealing property.
[0237] Furthermore, the inner periphery of the cylinder body (421),
the bottom surface of the front head (422) and the top surface of
the rear head (423), which define the cylinder chamber (425), may
be subjected to conversion treatment so that their substrates have
a surface roughness Ra of 1 .mu.m and lubrication layers made of
resin layers having a composition of PAI/FEP/PTFE=70/25/5 may be
then formed on the substrate surfaces. This improves the
slidability of the inside wall surface of the cylinder chamber
(425) on the surfaces sliding on the inside wall surface of the
cylinder (425): the top and bottom surfaces of the eccentric part
(433a), the top and bottom surfaces and outer periphery of the
piston (424), and the top and bottom surfaces of the blade (426).
Furthermore, the clearances in the sliding parts can be reduced,
thereby good sealing property. This enhances the reliability of
this machine as a compressor. The rest of the configuration, the
other operations and the other effects are the same as Embodiment
3.
Other Embodiments
[0238] The above embodiments may have the following
configurations.
[0239] In Embodiments 1 to 5, resin layers are formed as lubricants
on bearing parts or sliding parts, such as scrolls, cylinders and
pistons. However, if there is any other sliding part, a lubrication
part may be formed by likewise roughening the sliding part to have
a predetermined substrate surface roughness Ra and then forming a
resin layer containing fluorine-containing resin on the substrate
surface.
[0240] Furthermore, in Embodiments 1 to 5, the sliding elements of
the scroll compressors (10, 100), the swing compressors (200, 300)
and the rotary compressor (400) are roughened so that their
substrates have a predetermined surface roughness Ra and resin
layers containing fluorine-containing resin are then formed on the
substrate surfaces. The compressor used may be any type of
compressor that compresses a fluid. The fluid is not limited to
refrigerant. Furthermore, sliding elements according to the present
invention are not limited to those used in compressors.
Specifically, sliding elements according to the present invention
may be those in any fluid machines other than compressors or those
in any sliding parts, such as drive units or rotating parts in
vehicles or manufacturing apparatuses.
[0241] In the sliding part, one of two elements sliding on each
other may be roughened into a predetermined substrate surface
roughness Ra and a resin layer containing fluorine-containing resin
may be formed on the roughened surface. Alternatively, both the
members in the sliding part may be roughened into a predetermined
substrate surface roughness Ra and resin layers containing
fluorine-containing resin may be formed on both the roughened
surfaces.
[0242] The material of the substrate of the sliding element is not
limited to iron and may be selected from metals other than iron,
such as aluminum.
[0243] The treatment for roughening the substrate surface is not
limited to conversion treatment and various known surface
roughening processes, such as sand blasting, can be employed. The
chemical agent used for conversion treatment is not limited to
manganese phosphate and other phosphates or known chemical agents
can be employed.
INDUSTRIAL APPLICABILITY
[0244] As described so far, the sliding element and compressor
according to the present invention have excellent slidability and,
therefore, are useful for air conditioners, vehicles, manufacturing
apparatuses and machine tools.
* * * * *