U.S. patent application number 13/814076 was filed with the patent office on 2013-05-23 for scroll-type fluid machine.
The applicant listed for this patent is Sueji Hirawatari, Makoto Ijiri, Takayuki Kudo. Invention is credited to Sueji Hirawatari, Makoto Ijiri, Takayuki Kudo.
Application Number | 20130129550 13/814076 |
Document ID | / |
Family ID | 45559273 |
Filed Date | 2013-05-23 |
United States Patent
Application |
20130129550 |
Kind Code |
A1 |
Hirawatari; Sueji ; et
al. |
May 23, 2013 |
Scroll-Type Fluid Machine
Abstract
A scroll-type fluid machine in which: a fixed scroll and a
moveable scroll are disposed in a housing; a fluid pocket, the
volume of which varies, is formed between the fixed scroll and the
moveable scroll; and a thrust plate for receiving the reaction
force in the axial direction of pressure applied within the fluid
pocket is disposed between the bottom plate of the moveable scroll
and the housing. The scroll-type fluid machine is characterized in
that at least the surface of the thrust plate facing the bottom
plate of the moveable scroll is subjected to tin plating. As a
consequence, it is possible to efficiently produce, at a low cost,
a thrust bearing which is disposed between the bottom plate of the
moveable scroll and the housing, exerts excellent seizure
resistance, and has a high PV limit level and a low friction
coefficient.
Inventors: |
Hirawatari; Sueji;
(Isesaki-shi, JP) ; Ijiri; Makoto; (Isesaki-shi,
JP) ; Kudo; Takayuki; (Isesaki-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hirawatari; Sueji
Ijiri; Makoto
Kudo; Takayuki |
Isesaki-shi
Isesaki-shi
Isesaki-shi |
|
JP
JP
JP |
|
|
Family ID: |
45559273 |
Appl. No.: |
13/814076 |
Filed: |
June 30, 2011 |
PCT Filed: |
June 30, 2011 |
PCT NO: |
PCT/JP2011/065032 |
371 Date: |
February 4, 2013 |
Current U.S.
Class: |
418/55.1 |
Current CPC
Class: |
F04C 2240/80 20130101;
F05C 2201/0493 20130101; F01C 21/02 20130101; F01C 1/0215 20130101;
F04C 2230/91 20130101 |
Class at
Publication: |
418/55.1 |
International
Class: |
F01C 1/02 20060101
F01C001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 2, 2010 |
JP |
2010-173550 |
Claims
1. A scroll-type fluid machine in which a fixed scroll and a
movable scroll to revolve around the fixed scroll as being
prevented from rotating are provided to a housing, a fluid pocket
having a variable volume is provided between the fixed scroll and
the movable scroll, and a thrust plate to bear an axial reaction
force of a pressure applied into the fluid pocket is provided
between a bottom plate of the movable scroll and the housing,
characterized in that at least a surface of the thrust plate facing
the bottom plate of the movable scroll is plated with tin-based
metal.
2. The scroll-type fluid machine according to claim 1, wherein the
thrust plate is made of iron-based steel plate, cast metal or light
metal.
3. The scroll-type fluid machine according to claim 1, wherein the
thrust plate is provided with a base layer plated with the
tin-based metal.
4. The scroll-type fluid machine according to claim 3, wherein the
base layer is a nickel plating or a copper plating.
5. The scroll-type fluid machine according to claim 1, wherein the
base layer plated with the tin-based metal on the thrust plate has
a skewness Rsk defined by Formula 1 which is less or equal to -0.05
and a kurtosis Rku defined by Formula 2 which is more or equal to
+2.5, wherein the skewness Rsk and the kurtosis Rku are prescribed
in JISB0601 (corresponding to International Standard: ISO4287)
concerning surface roughness. Rsk = 1 Rq 3 [ 1 lr .intg. 0 lr Z 3 (
x ) x ] [ Formula 1 ] ##EQU00005## where, Z(x) is a function
showing a profile and Rq is a root-mean-square height of the
profile ( 1 l .intg. 0 l Z 2 ( x ) x ) . ##EQU00006## Rku = 1 Rq 4
[ 1 lr .intg. 0 lr Z 4 ( x ) x ] [ Formula 2 ] ##EQU00007## where,
Z(x) is a function showing a profile and Rq is a root-mean-square
height of the profile ( 1 l .intg. 0 l Z 2 ( x ) x ) .
##EQU00008##
6. The scroll-type fluid machine according to claim 1, wherein the
tin-based metal to be plated with has a thickness of 1-15
.mu.m.
7. The scroll-type fluid machine according to claim 1, wherein a
whole surface of the thrust plate is plated with the tin-based
metal.
8. The scroll-type fluid machine according to claim 1, wherein the
thrust plate is formed in a plurality of members divided
circumferentially.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to a scroll-type fluid
machine, and specifically relates to an improvement of a thrust
bearing interposed between a movable scroll bottom plate and a
housing.
BACKGROUND ART OF THE INVENTION
[0002] In a scroll-type fluid machine such as a scroll-type
compressor and a scroll-type expander, it is usual that a thrust
bearing member for receiving an axial reaction force, such as a
compression reaction force, to an inner pressure of a fluid pocket
formed between a fixed scroll and a movable scroll is provided
between a bottom plate of the movable scroll which revolves around
the fixed scroll as being prevented from rotating and a housing.
The thrust bearing member may be a thrust plate made with a
ring-shaped plate member. Such a thrust plate and such a bottom
plate of the movable scroll are required to have an excellent seize
resistance as well as a high PV limit level and a low coefficient
of friction which are enough to prevent both members from adhering
to each other.
[0003] With respect to such a requirement, Patent document 1
discloses a structure where a steel thrust bearing for receiving a
thrust load is provided between a movable scroll member and a front
housing and the bottom plate surface at the side of the movable
scroll is tinned in order to improve an abrasion resistance and a
seize resistance. Patent document 2 discloses a structure where
solid lubricant coating is formed on either of the outside of a
movable scroll end plate or a sliding surface of a trust bearing to
slide the end plate, or both.
PRIOR ART DOCUMENTS
Patent Documents
[0004] Patent document 1: JP8-247052-A
[0005] Patent document 2: JP8-061256-A
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0006] In the structure disclosed in Patent document 1, because a
certain part of the movable scroll having a complicated shape is
tinned, some parts must be masked or few number of movable scrolls
can be put at a time in the plating barrel, so as to cause problems
such as poor productivity and high cost.
[0007] In the structure disclosed in Patent document 2, there might
be a problem, that the forming cost of the solid lubricant coating
is high and a sufficiently high seize-resistance load is not
obtained because of less adhesion of the coating. In order to
improve the adhesion performance, it is possible that a chemical
treatment such as a chemical conversion treatment or a physical
treatment such as a shot blasting is processed between the thrust
plate base material and the coating layer. However, both treatments
may cause a high cost.
[0008] Accordingly, an object of the present invention is to
provide a scroll-type fluid machine which achieves excellent seize
resistance, high PV limit level and low coefficient of friction
with a low cost and a good productivity.
Means for Solving the Problems
[0009] To achieve the above-described object, a scroll-type fluid
machine according to the present invention is a scroll-type fluid
machine in which a fixed scroll and a movable scroll to revolve
around the fixed scroll as being prevented from rotating are
provided to a housing, a fluid pocket having a variable volume is
provided between the fixed scroll and the movable scroll, and a
thrust plate to bear an axial reaction force of a pressure applied
into the fluid pocket is provided between a bottom plate of the
movable scroll and the housing, characterized in that at least a
surface of the thrust plate facing the bottom plate of the movable
scroll is plated with tin-based metal. Here the tin-based metal for
plating includes tin alloy, as well as a single metal of tin.
[0010] In such a scroll-type fluid machine, a simple ring-shaped
plate of the thrust plate is plated with tin, so that a simple
masking would be enough even if a masking is required in the
plating process. Therefore, the plating can be achieved at a low
cost. Further, because the thrust plate is a member which has a
simple structure and is smaller than the movable scroll, more
number of thrust plates can be put at a time in the plating barrel.
With such a good operability and a good productivity, the plating
can be achieved at a low cost. Furthermore, even compared to a
solid lubricant coating film, a plated layer having a high adhesion
performance can be realized at a low cost. Additionally, because
the thrust plate is plated with tin, a good sliding performance is
ensured between the thrust plate and the bottom plate of the
movable scroll which faces thereof, and the sliding surface is
improved in its conformability so as to prevent defect such as a
seizing between the scroll and the thrust plate. As a result, the
seize resistance can be greatly improved at this part, so as to
obtain a high PV limit and a low coefficient of friction, and
therefore the durability can be greatly improved.
[0011] In the present invention, it is possible that a base
material of the thrust plate is made of iron-based steel plate,
cast metal or light metal. The light metal may be aluminum,
aluminum alloy, magnesium alloy, or titanium alloy. The iron-based
steel plate or the cast metal makes it possible that the
productivity is improved. The light metal can contribute to the
weight saving of the fluid machine.
[0012] It is possible that the thrust plate is provided with a base
layer plated with the tin-based metal. The base layer makes it
possible that the tin-based metal for plating adheres much better.
The base layer for plating may be a nickel plating or a copper
plating.
[0013] It is preferable that the base layer (a surface before
plating) plated with the tin-based metal on the thrust plate has a
predetermined surface aspect. Concretely, it is preferable that a
skewness Rsk defined by Formula 1 is less or equal to -0.05 and a
kurtosis Rku defined by Formula 2 is more or equal to +2.5, wherein
the skewness Rsk and the kurtosis Rku are prescribed in JISB0601
(corresponding to International Standard: ISO4287) concerning
surface roughness. It is more preferable that the skewness Rsk is
less or equal to -0.1 and the kurtosis Rku is more or equal to
+3.0. If the skewness Rsk and the kurtosis Rku are in such
preferable range, desirably high PV limit and desirably low
coefficient of friction can be achieved at the same time. Details
of the skewness Rsk and the kurtosis Rku will be explained later.
In order to satisfy the predetermined range of the surface aspect,
the following surface processing method may be employed. The base
material of the thrust plate is processed by cutting with a lathe,
and then is processed by a finish grinding process, so as to be
shaped with a predetermined surface roughness. In order to improve
the surface roughness practically, it is preferable that the
material is processed by a barrel finishing process according to
the barrel finishing method after the grinding. The barrel
finishing can easily form a surface having a predetermined surface
roughness.
Rsk = 1 Rq 3 [ 1 lr .intg. 0 lr Z 3 ( x ) x ] [ Formula 1 ]
##EQU00001##
where, Z(x) is a function showing a profile and Rq is a
root-mean-square height of the profile
( 1 l .intg. 0 l Z 2 ( x ) x ) . ##EQU00002##
Rku = 1 Rq 4 [ 1 lr .intg. 0 lr Z 4 ( x ) x ] [ Formula 2 ]
##EQU00003##
where, Z(x) is a function showing a profile and Rq is a
root-mean-square height of the profile
( 1 l .intg. 0 l Z 2 ( x ) x ) . ##EQU00004##
[0014] It is preferable that tin-based metal to be plated with has
a thickness of 1-15 .mu.m. The thickness is more preferably 2-12
.mu.m, and further preferably 3-10 .mu.m. If the thickness is set
within such ranges, the tin component filled in the valleys on the
plate surface makes up for the surface conformability even in a
case where several parts of the tinned layer of the thrust plate
surface have been exfoliated. If the thickness of tinned layer is
less than 1 .mu.m, the tinned layer might not be sufficiently
formed in valleys of the surface of base material, and therefore,
the superficial conformability is not easily ensured and the
lubrication might deteriorate. On the other hand, if the thickness
of tinned layer is more than 15 .mu.m, the loss of tinned layer
might fluctuate the dimension in an axial direction of the
compressor, so that the compressor functionality might be not
maintained even if the lubrication is ensured.
[0015] The plating method is not limited to a specific method. For
example, electroplating or non-electrolytic plating can be
employed. It is possible that a masking is performed before the
plating process. Alternatively, in order to simplify a preparation
operation, it is possible that a whole surface of the thrust plate
is plated with the tin-based metal.
[0016] It is possible that the thrust plate is formed in a
ring-shaped solid plate, and alternatively is formed in a plurality
of members divided circumferentially, which is divided into two
half-ring-shaped partitions, for example. It can be designed
arbitrarily from a viewpoint of workability in assembling, etc.
[0017] The structure of the scroll-type fluid machine according to
the present invention is applicable to both a scroll-type
compressor and scroll-type expander. The present invention is
applicable to a scroll-type fluid machine for vehicles, and
specifically to a scroll-type compressor for vehicles, which
strongly requires a high durability and a long life, and is
suitable to a scroll-type compressor in an air-conditioning system
for vehicles.
Effect According to the Invention
[0018] A scroll-type fluid machine according to the present
invention makes it possible that the sliding surface of the thrust
plate plated with a tin-based metal improves the conformability and
the movable scroll and the thrust plate are prevented from adhering
to each other, so that a high PV limit level and a low coefficient
of friction are achieved. A high productivity can also be achieved
because the cost can be reduced from a conventional process, such
as a film coating with a solid lubricant and a tin plating on a
scroll side.
BRIEF EXPLANATION OF THE DRAWINGS
[0019] FIG. 1 is a longitudinal section view of a scroll-type
compressor as a scroll-type fluid machine according to an
embodiment of the present invention.
[0020] FIG. 2 shows thrust plates, where (A) is a plan view of the
thrust plate of the scroll-type compressor in FIG. 1, (B) is a
schematic side view thereof and (C) is a schematic side view of a
thrust plate according to another embodiment.
[0021] FIG. 3 shows a thrust plate according to another embodiment,
where (A) is a plan view and (B) is a schematic side view.
[0022] FIG. 4 is a comparison chart of PV limit among various
layered films in a sliding test.
[0023] FIG. 5 is a comparison chart of coefficient of friction
among various layered films in a sliding test.
[0024] FIG. 6 is a relationship chart of skewness Rsk and PV
limit.
[0025] FIG. 7 is a relationship chart of kurtosis Rku and PV
limit.
[0026] FIG. 8 is a characteristic chart of surface roughness,
showing an example of surface aspect shift caused by skewness Rsk
shift.
[0027] FIG. 9 is a characteristic chart of surface roughness,
showing an example of surface aspect shift caused by kurtosis Rku
shift.
[0028] FIG. 10 is a schematic superficial section view of a thrust
plate, showing an example of surface aspect shift before and after
sliding while only skewness Rsk is in a specific range.
[0029] FIG. 11 is a schematic superficial section view of a thrust
plate, showing an example of surface aspect shift before and after
sliding while skewness Rsk and kurtosis Rku are both in each
specific range.
[0030] FIG. 12 is a schematic superficial section view of a thrust
plate, showing an example of surface aspect shift caused by tinned
plate thickness shift.
EMBODIMENTS FOR CARRYING OUT THE INVENTION
[0031] Hereinafter, desirable embodiments will be explained as
referring to figures.
[0032] FIG. 1 shows a scroll-type compressor 1 as a scroll-type
fluid machine according to an embodiment of the present invention.
In this embodiment of scroll-type compressor 1, a housing is
provided with fixed scroll 4 and movable scroll 5 which revolves
around fixed scroll 4 in a state prevented from rotating between
front housing 2 and rear housing 3, and fluid pocket 6 of which
volume is varied is formed between fixed scroll 4 and movable
scroll 5. Accompanying movable scroll 5 swinging, sealed fluid
pocket 6 is moved radially toward the center, so that the volume of
fluid pocket 6 is reduced so as to compress the fluid, such as
refrigerant, in fluid pocket 6. Tip seals 7 are attached to the tip
parts of scroll walls of fixed scroll 4 and movable scroll 5, so as
to contribute the sealing during compression movement. The
compressed fluid is discharged through a discharge hole perforated
at the central part in a radial direction of fixed scroll 4 to
discharge chamber 8, and then is delivered to the outside through
discharge port 9. Movable scroll 5 revolves as swinging in a
condition where its rotation is prevented by a rotation preventing
mechanism having rotation preventing pins 10. Movable scroll 5 is
driven with eccentric bush 11 which is rotatably positioned on the
back side of its bottom plate 5a, and main shaft 12 which is
eccentrically engaged with eccentric bush 11 as being rotatable
relatively. Main shaft 12 is supported by front housing 2 through
drive bearing 13 rotatably. The rotary driving force of main shaft
12 is transmitted through pulley 14 and electromagnetic clutch 15
from an external drive source (not shown).
[0033] Ring-shaped thrust plate 21, which receives an axial
reaction force to the pressure applied into fluid pocket 6, is
provided between bottom plate 5a of movable scroll 5 and front
housing 2. Thrust plate 21 and bottom plate 5a of movable scroll 5
move as sliding on each other, accompanied by the swing movement of
movable scroll 5. Thrust plate 21 is plated with tin-based material
at least on a surface facing bottom plate 5a of movable scroll
5.
[0034] Thrust plate 21 is configured to be a ring-shaped solid
plate member as shown in FIG. 2(A), and is plated with tinned layer
22 on the surface facing bottom plate 5a of movable scroll 5 of
thrust plate base material 21a as shown in FIG. 2(B). The surface
plated with tinned layer 22 is supposed to be sliding surface 23 to
slide on bottom plate 5a of movable scroll 5. Though FIG. 2(B)
shows an embodiment where thrust plate base material 21a is plated
with tinned layer 22 only on the surface facing bottom plate 5a of
movable scroll 5, it is possible that the tin-plating is applied to
both surfaces or all over thrust plate base material 21a from a
viewpoint of the workability in plating and the treatment
efficiency, etc. Alternatively, an interlayer such as base layer 24
of tinned layer 22 may be formed between thrust plate base material
21a and tinned layer 22, as shown in FIG. 2(C). Base layer 24 may
be a layer plated with nickel or copper, as described above. Base
layer 24 can make tinned layer 22 improve in adhesion. Plated
layers can be formed by electroplating or non-electrolytic
plating.
[0035] The thrust plate may be formed in a ring-shaped solid plate
shown in FIG. 2(A) as well as a plurality of members divided
circumferentially as shown in FIG. 3(A) and 3(B). In FIG. 3, thrust
plate 31 consists of two partitions. Each thrust plate base
material 31a is plated with tinned layer 32, and the surface plated
with tinned layer 32 is supposed to be sliding surface 33 to slide
on bottom plate 5a of movable scroll 5. The number of partitions
can be designed arbitrarily from a viewpoint of workability in
assembling and plating, and treating efficiency, etc.
[0036] With such a tinned thrust plate, specifically with thrust
plates of two kinds of which one is tinned and the other is tinned
with Nickel-plated base layer, the sliding test results of PV limit
and coefficient of friction are shown in FIGS. 4 and 5 which are
comparison charts of PV limit and coefficient of friction among
various layered films in a sliding test as compared with
resin-coated layer. The test has been conducted as a ring-on-plate
test, where the circumferential velocity is 6 m/s and the surface
pressure is 6 MPa, under a lubricating atmosphere. As shown in FIG.
4, PV limit levels of both a tinned layer and a tinned layer with a
Ni-plated base layer are higher than that of a resin coating.
Further, as shown in FIG. 5, coefficients of friction of both the
tinned layer and the tinned layer with a Ni-plated base layer are
stably lower than that of the resin coating for a long time.
[0037] As described above, it is preferable that skewness Rsk
defined by the above-described Formula 1 is less or equal to -0.05
and kurtosis Rku defined by the above-described Formula 2 is more
or equal to +2.5, wherein parameters prescribed in JISB0601
(corresponding to International Standard: ISO4287) concerning
surface roughness are determined for the surface aspect of a base
layer (surface which has not been plated yet) of the tinned layer
of the thrust plate. It is more preferable that skewness Rsk is
less or equal to -0.1 and kurtosis Rku is more or equal to +3.0.
The above-described ranges of skewness Rsk and kurtosis Rku have
been specified so as to achieve PV limit more or equal to 20
MPam/s, as much as an appropriate sliding performance is expected.
Namely, such parameter ranges are specified as ranges to achieve PV
limit more or equal to 20 MPam/s, while the relationship between
skewness Rsk and limit PV and the relationship between kurtosis Rku
and PV limit are shown in FIGS. 6 and 7.
[0038] With FIG. 8 and FIG. 9, skewness Rsk and kurtosis Rku can be
more clearly understood in their concept. As shown in FIG. 8, when
skewness Rsk is less or equal to -0.05, peak widths increase and
the surface area becomes greater. Therefore, because the contact
area to slide on the movable scroll increases, the surface pressure
load bearing can be increased. On the other hand, when skewness Rsk
is less or equal to -0.05, it is difficult to obtain high sliding
performance, because the number of valleys decreases so that tin
filled in valleys is not enough to keep lubrication. Even in such a
condition, when kurtosis Rku is more or equal to 2.5, peaks of the
roughness profile become sharper so as to form sufficiently many
valleys as shown in FIG. 9. Therefore tin and other lubrication
components can be held to enhance lubrication. Consequently a high
sliding performance can be achieved. Thus, the thrust plate base
material having a surface roughness, where skewness Rsk of less or
equal to -0.05 and kurtosis Rku of more or equal to 2.5, is tinned,
so that the contact area increases to improve the surface pressure
load capacity and that the number of the surface valleys increases
to fill a large number of the surface valleys with conformable tin
plating component, so as to achieve highly enhanced lubrication and
small coefficient of friction.
[0039] Further, if such a surface aspect is achieved, even in a
case where several parts of the tinned layer of the thrust plate
surface have been exfoliated, it is possible that tin filled in the
surface valleys makes up for the conformability of the surface.
Thus, even if the skewness Rsk of the base material surface is less
or equal to -0.05, the lubrication might deteriorate because the
number of valleys decreases as shown in FIG. 10 so as not to
exhibit good superficial conformability by tin filled in the
valleys, in spite of its great width. Accordingly, if a surface
aspect, such that skewness Rsk is less or equal to -0.05 and
kurtosis Rku is more or equal to 2.5 or less, is ensured as shown
in FIG. 11, the number of valleys increases, so that tin filled
therein develops sufficient superficial conformability as well as
lubrication retention.
[0040] Further, it is preferable that thickness of the tinned layer
is 1-15 .mu.m, as described above. It is more preferably 2-12
.mu.m, and is further preferably 3-10 .mu.m. Such designed
thickness, such as around 5 .mu.m as the thickness of tinned layer
42 on base material 41 shown in FIG. 12(B), makes it possible that
tin filled in valleys on the surface sufficiently makes up for the
conformability of the surface, even in a case where exfoliation of
the tinned layer of the thrust plate surface has progressed. As
shown in FIG. 12(A), if the thickness of tinned layer 42 is less
than 1 .mu.m, the tinned layer might not be sufficiently formed in
valleys of the surface of base material 41, and therefore, the
superficial conformability is not easily ensured and the
lubrication might deteriorate. Further, as shown in FIG. 12(C), if
the thickness of tinned layer 42 is more than 15 .mu.m, the loss of
tinned layer 42 might fluctuate the dimension in an axial direction
of the compressor (plate thickness direction), so that the
compressor functionality is not maintained even if the lubrication
is ensured.
[0041] Furthermore, in order to confirm the above-described ranges
as preferable conditions, the ring-on-plate sliding test has been
conducted under lubrication atmosphere in various conditions of
thrust plates. The test has been conducted while the
circumferential velocity has been constant and the surface pressure
has been gradually increased at a constant speed. Here, PV limit is
defined as a product of circumferential velocity (V) and surface
pressure (P) at a time when the coefficient of friction suddenly
increases (when coefficient of friction becomes more or equal to
0.03). The criteria are the following.
[0042] PV limit: o (Good); if the level is more or equal to 20
MPam/s, x (No Good); otherwise
[0043] Coefficient of friction: o (Good); if the level is less than
0.04, x (No Good); otherwise
[0044] The results are shown in Table 1 and Table 2.
TABLE-US-00001 TABLE 1 Surface Sliding performance roughness
Plating Coefficient Determination Rsk Rku thickness PV limit of
friction PV Coefficient [.mu.m] [.mu.m] [.mu.m] [MPa m/s] [--]
limit of friction Example 1 -1.66 6.76 5.4 44 0.03 .smallcircle.
.smallcircle. Example 2 -0.42 3.25 2.5 38 0.03 .smallcircle.
.smallcircle. Comparative -0.13 1.46 5.1 22 0.06 .smallcircle. x
Example 1 Comparative 0.22 2.13 4.3 16 0.04 x x Example 2
Comparative 1.12 1.53 6.8 11 0.06 x x Example 3
TABLE-US-00002 TABLE 2 Surface roughness Plating Determination Rsk
Rku thickness Seize Coefficient [.mu.m] [.mu.m] [.mu.m] resistance
of friction Example 1 -1.66 6.76 5.4 .largecircle. .largecircle.
Comparative -1.32 4.12 0.8 X .largecircle. Example 1 Comparative
-2.13 3.12 0.5 X X Example 2
[0045] As shown in Table 1 and Table 2, it has been confirmed that
the preferable conditions according to the present invention can
achieve both of desirable high PV limit and low coefficient of
friction.
Industrial Applications of the Invention
[0046] The structure of a scroll-type fluid machine is applicable
to any of a scroll-type compressor and a scroll-type expander, and
is suitable to a fluid machine for vehicles which strongly requires
a high durability and a long life. Above all it is suitable to a
scroll-type compressor for vehicles, and is specifically suitable
to a scroll-type compressor provided in an air-conditioning system
for vehicles.
Explanation of Symbols
[0047] 1: scroll-type compressor
[0048] 2: front housing
[0049] 3: rear housing
[0050] 4: fixed scroll
[0051] 5: movable scroll
[0052] 5a: bottom plate of movable scroll
[0053] 6: fluid pocket
[0054] 7: tip seal
[0055] 8: discharge chamber
[0056] 9: discharge port
[0057] 10: rotation preventing pin
[0058] 11: eccentric bush
[0059] 12: main shaft
[0060] 13: drive bearing
[0061] 14: pulley
[0062] 15: electromagnetic clutch
[0063] 21, 31: thrust plate
[0064] 21a, 31a: thrust plate base material
[0065] 22, 32: tinned layer
[0066] 23, 33: sliding surface
[0067] 24: base layer
[0068] 41: base material
[0069] 42: tinned layer
* * * * *