U.S. patent application number 13/824694 was filed with the patent office on 2013-07-25 for rotary compressor.
This patent application is currently assigned to PANASONIC CORPORATION. The applicant listed for this patent is Daisuke Funakoshi, Noboru Iida, Tsuyoshi Karino, Hiroaki Nakai, Ryuichi Ohno, Shingo Oyagi, Hirofumi Yoshida. Invention is credited to Daisuke Funakoshi, Noboru Iida, Tsuyoshi Karino, Hiroaki Nakai, Ryuichi Ohno, Shingo Oyagi, Hirofumi Yoshida.
Application Number | 20130189080 13/824694 |
Document ID | / |
Family ID | 45892317 |
Filed Date | 2013-07-25 |
United States Patent
Application |
20130189080 |
Kind Code |
A1 |
Nakai; Hiroaki ; et
al. |
July 25, 2013 |
ROTARY COMPRESSOR
Abstract
A refrigerant being low in both ODP and GWP and containing at
least hydrofluoroolefin having a double bond of carbon is used. By
providing a first compression-chamber oil feed path for feeding
refrigerating machine oil to a compression chamber 15 after the
refrigerant has been enclosed therein, effects on the global
environment can be suppressed and moreover temperature increases of
the refrigerant due to re-expansion heating and feeding of
high-temperature refrigerating machine oil can be suppressed, i.e.,
decomposition of the refrigerant can be inhibited.
Inventors: |
Nakai; Hiroaki; (Shiga,
JP) ; Oyagi; Shingo; (Kyoto, JP) ; Yoshida;
Hirofumi; (Shiga, JP) ; Karino; Tsuyoshi;
(Shiga, JP) ; Funakoshi; Daisuke; (Shiga, JP)
; Ohno; Ryuichi; (Shiga, JP) ; Iida; Noboru;
(Shiga, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nakai; Hiroaki
Oyagi; Shingo
Yoshida; Hirofumi
Karino; Tsuyoshi
Funakoshi; Daisuke
Ohno; Ryuichi
Iida; Noboru |
Shiga
Kyoto
Shiga
Shiga
Shiga
Shiga
Shiga |
|
JP
JP
JP
JP
JP
JP
JP |
|
|
Assignee: |
PANASONIC CORPORATION
Osaka
JP
|
Family ID: |
45892317 |
Appl. No.: |
13/824694 |
Filed: |
September 26, 2011 |
PCT Filed: |
September 26, 2011 |
PCT NO: |
PCT/JP2011/005395 |
371 Date: |
March 18, 2013 |
Current U.S.
Class: |
415/116 |
Current CPC
Class: |
F04C 18/356 20130101;
F04C 18/0292 20130101; F04C 18/0207 20130101; F04C 2210/26
20130101; F04D 17/00 20130101; F04C 2210/263 20130101; F04C 29/042
20130101 |
Class at
Publication: |
415/116 |
International
Class: |
F04D 17/00 20060101
F04D017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2010 |
JP |
2010-214877 |
Claims
1. A rotary compressor in which a single refrigerant of
hydrofluoroolefin having a double bond of carbon or a mixed
refrigerant containing the hydrofluoroolefin is used, the rotary
compressor comprising: a compression chamber for compressing the
refrigerant; and a first compression-chamber oil feed path for
feeding refrigerating machine oil to the compression chamber after
the refrigerant has been enclosed therein.
2. The rotary compressor according to claim 1, wherein the first
compression-chamber oil feed path is intermittently closed.
3. The rotary compressor according to claim 1, wherein the
compression chamber is defined between a stationary scroll and a
turning scroll by the stationary scroll and the turning scroll
being engaged with each other, each of the stationary scroll and
the turning scroll including an end plate and a lap being a
volute-shaped wall formed on the end plate, the rotary compressor
further comprising: an oil storage section for storing the
refrigerating machine oil therein; and at least one or more second
compression-chamber oil feed paths for feeding the refrigerating
machine oil from the oil storage section to the compression
chamber, and wherein at least one of the second compression-chamber
oil feed paths is the first compression-chamber oil feed path.
4. The rotary compressor according to claim 3, wherein the
compression chamber includes a first compression chamber formed
outside the lap of the turning scroll, and a second compression
chamber formed inside the lap of the turning scroll, and in
comparison between the first compression chamber and the second
compression chamber, a feed rate of the refrigerating machine oil
to one compression chamber having a longer leak length is larger
than a feed rate of the refrigerating machine oil to the other
compression chamber.
5. The rotary compressor according to claim 3, wherein the
compression chamber includes a first compression chamber formed
outside the lap of the turning scroll, and a second compression
chamber formed inside the lap of the turning scroll, and in
comparison between the first compression chamber and the second
compression chamber, a feed rate of the refrigerating machine oil
to one compression chamber having a higher capacity change rate is
larger than a feed rate of the refrigerating machine oil to the
other compression chamber.
6. The rotary compressor according to claim 3, wherein the first
compression-chamber oil feed path comprises: a lead-in path part
provided in a back face of the turning scroll so as to allow the
refrigerating machine oil to be led in from the oil storage
section; an in-lap oil feed path part which is provided inside the
lap of the turning scroll so as to be communicated with the lead-in
path part and which has an opening in a lap top face; and a recess
portion which is provided in the end plate of the stationary scroll
and which is intermittently communicated with the opening of the
in-lap oil feed path pan.
7. The rotary compressor according to claim 1, wherein the
refrigerant contains at least one of tetrafluoropropene or
trifluoropropene, which is a kind of hydrofluoroolefin, and the
refrigerant has a global warming, potential within a range of 5 to
750, desirably 5 to 350.
8. The rotary compressor according to claim 1, wherein the
refrigerant contains, as a principal ingredient, tetrafluoropropene
or trifluoropropene, which is a kind of hydrofluoroolefin, and
difluoromethane and pentafluoroethane are mixed in the refrigerant
so that its global warn potential falls within a range of 5 to 750,
desirably 5 to 350.
9. The rotary compressor according to claim 1, wherein the
refrigerating machine oil is (1) polyoxyalkylene glycol, (2)
polyvinyl ether, (3) poly(oxy)alkylene glycol or copolymer of its
monoether and polyvinyl ether, (4) synthetic oil containing an
oxygenated compound of polyol esters and polycarbonates, (5)
synthetic oil containing alkylbenzenes as a principal ingredient,
or (6) synthetic oil containing .alpha.-olefins as a principal
ingredient.
Description
TECHNICAL FIELD
[0001] The present invention relates to a rotary compressor which
uses a refrigerant containing no chlorine atoms, being low in GWP
(Global Warming Potential) and containing at least
hydrofluoroolefin having a double bond of carbon, and which is to
be incorporated into refrigerating cycle apparatuses for room air
conditioners, automotive air conditioners, refrigerators and other
air conditioning equipment.
BACKGROUND ART
[0002] is Refrigerants for use in refrigerating cycle apparatuses
have been moving to HFC (hydrofluorocarbon)-related refrigerants
(hereinafter, referred to as `HFC refrigerant`) having an ODP
(Ozone Depletion Potential) of 0. However, the HFC refrigerants are
very high in GWP. Accordingly, there have been being developed
compressors using refrigerants that are low in ODP and GWP.
Unfortunately, refrigerants being low in GWP are, in general, low
in stability. Thus, there is a need for ensuring stability and
reliability of the refrigerant for its long-term use in
refrigerating cycle apparatuses for room air conditioners,
automotive air conditioners, refrigerators and other air
conditioning equipment.
[0003] With use of refrigerants composed principally of
hydrofluoroolefin containing no chlorine atoms and being low in GWP
and moreover having a double bond of carbon, there are problems as
follows. Such refrigerants, having a characteristic of high
decomposability at high temperatures, will be decomposed due to
high temperatures when elevated to the high temperatures by
over-compression or re-expansion. Therefore, these refrigerants are
low in stability. Particularly when those refrigerants are used for
long time in room air conditioners, automotive air conditioners,
refrigerators and other air conditioning equipment, decomposition
of the refrigerants due to high temperatures keeps occurring over
long periods, giving rise to a need for measures against
temperature increases of the refrigerants.
[0004] In a refrigerating cycle, a refrigerant evaporated by an
evaporator is sucked into a compressor and compressed to a
prescribed pressure by the compressor. During this process, the
refrigerant changes in state largely from low to high pressure and
from low to high temperature. Therefore, the compressor needs to be
made up so that stability and reliability of the refrigerant can be
ensured.
[0005] For example, PTL 1 discloses a compressor which uses a
refrigerant of low GWP and which has a direct suction path for
feeding the refrigerant directly to a suction port so that
compression of the refrigerant sucked to inside of the compressor
is started at as low temperatures as possible. With such an
arrangement, temperature increases of the refrigerant before
compression start are suppressed, compared with a case where the
refrigerant is temporarily stored in a storage space such as a
crankcase before being fed to a compression chamber. By virtue of
the suppression of temperature increases before the compression
start, the temperature of the refrigerant after its compression to
the prescribed pressure by the compressor is lower than that of the
case where the refrigerant is not directly fed to the suction port.
As a result, decomposition of the refrigerant is inhibited, so that
faults or life reduction of the compressor due to decomposition
products (e.g., sludge) of the refrigerant is suppressed. That is,
reliability and durability of the compressor are improved.
CITATION LIST
Patent Literature
[0006] PTL 1: JP 2009-228473 A
SUMMARY OF INVENTION
Technical Problem
[0007] However, even with suppression of temperature increases of
the refrigerant before compression start, there are some cases
where the temperature of the refrigerant after its compression to
the prescribed pressure by the compressor becomes higher than
necessary, so that the refrigerant may be decomposed. Among causes
for this case is `re-expansion heating.` The `re-expansion heating`
refers to a phenomenon that a high-pressure refrigerant under
compression is leaked into a low-pressure space so as to be
re-expanded to a high temperature in the low-pressure space so that
the low-pressure refrigerant present in the low-pressure space is
heated resultantly. By such re-expansion heating, the refrigerant
having been compressed to a prescribed pressure becomes higher than
necessary temperatures. Also, in the event of re-expansion heating,
part of compression power (energy) spent to obtain a
high-temperature, high-pressure refrigerant is used for heating of
the low-temperature, low-pressure refrigerant, causing the
compressor efficiency to lower.
[0008] As a method for suppressing such re-expansion heating due to
leakage of the refrigerant under compression, it is conceivable
that a refrigerating machine oil is fed to the refrigerant before
compression start (suction process) so as to improve sealability of
the compression chamber after the refrigerant has been enclosed
therein. However, there is a problem that the refrigerant before
compression start (suction process) is heated by higher-temperature
oil than the refrigerant.
[0009] Accordingly, with an aim of solving the above-described
problems, an object of the present invention is to provide a rotary
compressor which uses a refrigerant of low GWP and which is capable
of suppressing the re-expansion heating by improving the
sealability of the compression chamber by using a refrigerating
machine oil and moreover capable of suppressing the heating of the
refrigerant by the refrigerating machine oil, thus the rotary
compressor being excellent in reliability and durability and
moreover high in efficiency.
Solution to Problem
[0010] In order to achieve the above object, the present invention
has the following constitutions.
[0011] In order to solve the above-described problems, in one
aspect of the present invention, there is provided a rotary
compressor in which
[0012] a single refrigerant of hydrofluoroolefin having a double
bond of carbon or a mixed refrigerant containing the
hydrofluoroolefin is used, the rotary compressor comprising:
[0013] a compression chamber for compressing the refrigerant;
and
[0014] a first compression-chamber oil feed path for feeding
refrigerating machine oil to the compression chamber after the
refrigerant has been enclosed therein.
[0015] A refrigerating machine oil is fed to the compression
chamber after the refrigerant has been enclosed therein, by which
the sealability of the compression chamber is improved so that the
re-expansion heating due to leakage of the refrigerant under
compression is suppressed and moreover heating of the refrigerant
by the refrigerating machine oil is suppressed as compared with
cases in which the refrigerating machine oil is fed in the suction
process. As a result, the temperature of the refrigerant after its
compression to a prescribed pressure becomes lower than those in
cases where the refrigerating machine oil is fed in the suction
process, thus decomposition of the refrigerant being inhibited.
[0016] As compared with a case where the refrigerating machine oil
is fed in the suction process, the temperature of the refrigerant
after its compression to a prescribed pressure becomes lower in the
case where the refrigerating machine oil is fed to the compression
chamber after the refrigerant has been enclosed therein. The reason
of this is as follows.
[0017] The refrigerant under suction into the compression chamber
(under suction process) is the lowest in temperature. When a
high-temperature refrigerating machine oil is fed to such a
refrigerant, the refrigerant is strongly heated because of a large
temperature difference between the refrigerant and the
refrigerating machine oil (as a result, decomposition of the
refrigerant progresses to a large extent). In contrast to this, the
refrigerant under compression increases in temperature of the
refrigerant itself along with the compression, resulting in a small
temperature difference from the fed refrigerating machine oil. In a
case of the refrigerant further compressed to near the discharge
pressure, the temperature of the refrigerant has become higher than
the temperature of the fed refrigerating machine oil. Accordingly,
heating of the refrigerant by the refrigerating machine oil can be
suppressed more in the case where the refrigerating machine oil is
fed to the compression chamber after the refrigerant has been
enclosed therein (compression process). Thus, not by feeding the
refrigerating machine oil in suction process but by feeding the
refrigerating machine oil in compression process, heating of the
refrigerant can be suppressed while the sealability of the
compression chamber after the refrigerant has been enclosed therein
can be improved by the refrigerating machine oil. In addition,
desirably, the refrigerating machine oil is fed at such a timing
that its temperature difference from the refrigerant becomes as
small as possible.
Advantageous Effects of Invention
[0018] According to the present invention, in a rotary compressor,
with use of a refrigerant being low in both ODP and GWP,
temperature increases of the refrigerant, which could cause
decomposition of the refrigerant, can be suppressed. As a result,
there can be provided a rotary compressor being excellent in
reliability and durability and having high efficiency with
considerations given to the global environment.
BRIEF DESCRIPTION OF DRAWINGS
[0019] The above aspects and features of the present invention will
become more apparent from the following description of preferred
embodiments thereof with reference to the accompanying drawings,
and wherein:
[0020] FIG. 1 is a sectional view of a scroll compressor according
to Embodiment 1 of the invention;
[0021] FIG. 2 is a partly enlarged sectional view of a compression
mechanism of the scroll compressor according to Embodiment 1;
[0022] FIG. 3 is a view showing a plurality of states of a turning
scroll of the scroll compressor according to Embodiment 1;
[0023] FIG. 4 is a partly enlarged sectional view of a compression
mechanism of a scroll compressor according to Embodiment 2 of the
invention;
[0024] FIG. 5 is a view showing a plurality of states of a turning
scroll of the scroll compressor according to Embodiment 2;
[0025] FIG. 6 is a sectional view of a rotary compressor according
to Embodiment 3 of the invention;
[0026] FIG. 7 is an enlarged sectional view of a compression
mechanism of the rotary compressor according to Embodiment 3;
[0027] FIG. 8 is an assembly structural view of the compression
mechanism of the rotary compressor according to Embodiment 3;
and
[0028] FIG. 9 is a view showing a plurality of states of the
compression mechanism of the rotary compressor according to
Embodiment 3.
DESCRIPTION OF EMBODIMENTS
[0029] In a rotary compressor according to one aspect of invention,
a single refrigerant of hydrofluoroolefin having a double bond of
carbon or a mixed refrigerant containing the hydrofluoroolefin is
used, the rotary compressor comprises a compression chamber for
compressing the refrigerant; and a first compression-chamber oil
feed path for feeding refrigerating machine oil to the compression
chamber after the refrigerant has been enclosed therein. By the use
of a refrigerant being low in both ODP and GWP, effects on the
global environment can be suppressed. Also, with an aim of solving
the problem that a single refrigerant (or mixed refrigerant) of
hydrofluoroolefin having a double bond of carbon is easily
decomposable at high temperatures, the refrigerating machine oil is
fed to the compression chamber after the refrigerant has been
enclosed therein. By doing so, sealability of the compression
chamber is improved, so that the re-expansion heating due to
leakage of the refrigerant under compression is suppressed and
moreover temperature increases of the refrigerant due to the
feeding of the refrigerating machine oil are suppressed as compared
with cases in which the refrigerating machine oil is fed in the
suction process (before the refrigerant is enclosed in the
compression chamber). As a result, the temperature of the
refrigerant after its compression to a prescribed pressure becomes
lower, as compared with cases where the refrigerating machine oil
is fed in the suction process, so that decomposition of the
refrigerant is inhibited. Thus, there can be provided a rotary
compressor being excellent in reliability and durability and having
high efficiency with considerations given to the global
environment.
[0030] The rotary compressor may be configured that the first
compression-chamber oil feed path is intermittently dosed. The
refrigerating machine oil can be fed to the compression chamber at
such an optimum timing and an optimum quantity that improvement of
the sealability of the compression chamber as well as suppression
of temperature increases of the refrigerant due to the feeding of
the refrigerating machine oil can be effectively fulfilled. As a
result, temperature increases of the refrigerant due to the feeding
of the refrigerating machine oil and re-expansion heating due to
the leakage of the refrigerant can be suppressed further
securely.
[0031] In case the compression chamber is defined between a
stationary scroll and a turning scroll by the stationary scroll and
the turning scroll being engaged with each other, each of the
stationary scroll and the turning scroll including, an end plate
and a lap being a volute-shaped wall formed on the end plate, the
rotary compressor may comprise an oil storage section for storing
the refrigerating machine oil therein; and at least one or more
second compression-chamber oil feed paths for feeding the
refrigerating machine oil from the oil storage section to the
compression chamber, and wherein at least one of the second
compression-chamber oil feed paths is the first compression-chamber
oil feed path.
[0032] Generally, with a rotary compressor which includes a
plurality of compression chambers and in which the refrigerant in
the plurality of compression chambers is compressed simultaneously,
in a case where the refrigerant being under compression and having
been compressed to some extent of high pressure leaks to the
lower-pressure side compression chamber, the leak of the
refrigerant is more likely to occur (so-called internal leakage
occurs) not in the compression chamber under suction of the
refrigerant but in the compression chamber being under
one-process-later compression process. In such a case, re-expansion
of the leaked refrigerant causes not only heating of the
refrigerant in the leakage-destination compression chamber but also
pressure increases in the leakage-destination compression chamber.
As a result of such internal leakage, the refrigerant temperature
increases. As a countermeasure for this, providing at least one
second compression-chamber oil feed path for feeding the
refrigerating machine oil to the compression chamber makes it
possible to improve the sealability of the compression chamber
involved in occurrence of the internal leakage, which particularly
contributes to temperature increases of the refrigerant, by using
an optimum quantity of the refrigerating machine oil. Also, by the
use of an optimum quantity, of the refrigerating machine oil,
heating of the refrigerant due to excess refrigerating machine oil,
which could be caused by the feeding of excessive quantities of the
refrigerating machine oil, can also be suppressed.
[0033] In case the compression chamber includes a first compression
chamber formed outside the lap of the turning scroll and a second
compression chamber formed inside the lap of the turning scroll, in
comparison between the first compression chamber and the second
compression chamber, a feed rate of the refrigerating machine oil
to one compression chamber having a longer leak length may be
larger than a feed rate of the refrigerating machine oil to the
other compression chamber. Since the feed rate of the refrigerating
machine oil can be optimized to improve the sealability in
correspondence to the length of the leakage portion of the
compression chamber, heating of the refrigerant due to excess
refrigerating machine oil, which could be caused by feeding of
excessive quantities of refrigerating machine oil, can also be
suppressed.
[0034] In case the compression chamber includes a first compression
chamber formed outside the lap of the turning scroll, and a second
compression chamber formed inside the lap of the turning scroll, in
comparison between the first compression chamber and the second
compression chamber, a feed rate of the refrigerating machine oil
to one compression chamber having a higher capacity change rate may
be larger than a feed rate of the refrigerating machine oil to the
other compression chamber. By an optimum quantity of the
refrigerating machine oil, the sealability of the compression
chamber, in which leakage of the refrigerant is more likely to
occur because of a large pressure difference from the
lower-pressure side compression chamber, can be improved. Heating
of the refrigerant due to excess refrigerating machine oil, which
could be caused by feeding of excessive quantities of refrigerating
machine oil, can also be suppressed.
[0035] The first compression-chamber oil feed path may comprise a
lead-in path part provided in a back face of the turning scroll so
as to allow the refrigerating machine oil to be led in from the oil
storage section; an in-lap oil feed path part which is provided
inside the lap of the turning scroll so as to be communicated with
the lead-in path part and which has an opening in a lap top face;
and a recess portion which is provided in the end plate of the
stationary scroll and which is intermittently communicated with the
opening of the in-lap oil feed path part. As a result of this, it
becomes possible to feed the refrigerating machine oil in
particular periods to the compression chamber after the refrigerant
has been enclosed therein, while it becomes easier to achieve
control of the feed rate of the refrigerating machine oil. Further,
back flow of the compressed refrigerant to the first
compression-chamber oil feed path can be prevented, making it
possible to realize a scroll compressor of high reliability.
[0036] The refrigerant may contain at least one of
tetrafluoropropene or trifluoropropene, which is a kind of
hydrofluoroolefin, and the refrigerant has a global warming
potential within a range of 5 to 750, desirably 5 to 350. With such
a refrigerant, there can be provided a rotary compressor of low
environmental load, high reliability and high efficiency.
[0037] The refrigerant may contain, as a principal ingredient,
tetrafluoropropene or trifluoropropene, which is a kind of
hydrofluoroolefin, and difluoromethane and pentafluoroethane are
mixed in the refrigerant so that its global warming potential falls
within a range of 5 to 750, desirably 5 to 350. With such a
refrigerant, smaller environmental loads are involved and moreover
the flow velocity can be suppressed to lower the temperature. Thus,
a rotary compressor of high reliability and high efficiency can be
provided effectively.
[0038] The refrigerating machine oil may be (1) polyoxyalkylene
glycol, (2) polyvinyl ether, (3) poly(oxy)alkylene glycol or
copolymer of its monoether and polyvinyl ether, (4) synthetic oil
containing an oxygenated compound of polyol esters and
polycarbonates, (5) synthetic oil containing alkylbenzenes as a
principal ingredient, or (6) synthetic oil containing
.alpha.-olefins as a principal ingredient. With such refrigerating
machine oil, a rotary compressor of high reliability and high
efficiency can be provided effectively.
[0039] Hereinbelow, embodiments of the present invention will be
described with reference to the accompanying drawings. It is noted
that the invention is not limited by these embodiments.
[0040] In compressors according to three embodiments of the
invention described below, a single refrigerant of
hydrofluoroolefin having a double bond of carbon or a mixed
refrigerant containing the hydrofluoroolefin is used.
Embodiment 1
[0041] FIG. 1 is a longitudinal sectional view of a scroll
compressor according to Embodiment 1 of the invention. FIG. 2 is a
partly enlarged sectional view of a compression mechanism shown in
FIG. 1. FIG. 3 is a view showing a plurality of states of a turning
scroll of the compression mechanism. The scroll compressor will be
described below in terms of its operation and function.
[0042] The scroll compressor of this Embodiment 1 has a dosed
container 1 as shown in FIG. 1. The scroll compressor also has a
compression mechanism 2, a motor section 3 and an oil storage
section 20 inside the closed container 1. The compression mechanism
2 is made up of a main bearing member 11 fixed to the closed
container 1 by welding or shrinkage fit or the like, a shaft 4
supported by the main bearing member 11, a stationary scroll 12
fixed onto the main bearing member 11 with a bolt or the like, and
a turning scroll 13 placed between the main bearing member 11 and
the stationary scroll 12 so as to be engaged with the stationary
scroll 12.
[0043] The stationary scroll 12 includes an end plate 12a, and a
lap 12b that is a volute-shaped wall formed on the end plate 12a,
while the turning scroll 13 includes an end plate 13a, and a lap
13b that is a volute-shaped wall formed on the end plate 13a. An
automatic constraint mechanism 14, including Oldham's ring or the
like for preventing self-rotation of the turning scroll 13 and for
guiding in a way that the turning scroll 13 driven by the shaft 4
makes motion on a circular orbit is provided between the turning
scroll 13 and the main bearing member 11. An eccentric shaft part
4a located at an upper end of the shaft 4 makes the turning scroll
13 eccentrically turned, by which the circular-orbit turning motion
of the turning scroll 13 is fulfilled.
[0044] With the construction shown above, a compression chamber 15
defined between the stationary scroll 12 and the turning scroll 13
is moved from outer peripheral side toward center while reducing
its capacity. Via a suction pipe 16 communicating with outside of
the closed container 1 and a suction port 17 in an outer peripheral
part of the stationary scroll 12, a refrigerant (gas) is sucked
into the compression chamber 15 (suction process). After the
compression chamber 15 is closed by turning motion of the turning
scroll 13 (after the refrigerant is enclosed in the compression
chamber 15), the refrigerant is compressed (compression process).
The refrigerant having reached a prescribed pressure by the
compression pushes and opens a lead valve 19 provided at a
discharge hole 18 in a central portion of the stationary scroll 12,
thus the refrigerant moving from the compression chamber 15 via the
discharge hole 18 into the closed container 1.
[0045] Also, a pump 25 is provided at the other end of the shaft 4.
The pump 25 is so placed that its suction opening is present within
the oil storage section 20 provided at a bottom portion of the
closed container 1. Since the pump 25 is driven in synchronism with
the compression mechanism 2, the pump 25 is enabled to securely
suck up refrigerating machine oil 6 stored in the oil storage
section 20, and further stably feed the oil to the compression
mechanism 2, irrespective of pressure conditions or operating
speed. The oil 6 sucked up by the pump 25 is passed through an oil
feed hole 26 extending through inside the shaft 4 so as to be fed
to the compression mechanism 2. In addition, by removing foreign
matters from within the oil 6 with an oil filter or the like before
or after the sucking-up by the pump 25, mixing of foreign matters
into the compression mechanism 2 can be prevented, so that the
reliability of the compressor can be further improved.
[0046] A pressure of the oil 6 introduced into the compression
mechanism 2, being generally equal to a discharge pressure of the
scroll compressor, serves as a back pressure source for the turning
scroll 13. That is, the oil 6 fulfills a role of pressing a back
face (surface facing the main bearing member 11) of the turning
scroll 13 to push the turning scroll 13 against the stationary
scroll 12. As a result of this, the turning scroll 13 is kept in
contact with the stationary scroll 12 without separating from the
stationary scroll 12 and without partly contacting the stationary
scroll 12. Thus, the compression mechanism 2 is enabled to fulfill
specified compression power with stability. Further, part of the
oil 6 enters, by the feed pressure or deadweight, into a fitting
portion between the eccentric shaft part 4a and the turning scroll
13 as well as to a bearing portion 66 provided between the shaft 4
and the main bearing member 11 and serves for lubrication. The oil
6 after the lubrication falls down to return to the oil storage
section 20 as indicated by arrows in FIG. 2.
[0047] Also, a seal member 78 is placed between the back face of
the turning scroll 13 and the main bearing member 11 so that a
high-pressure region 30 is defined inside the seal member 78 while
a back pressure chamber 29 is defined outside the seal member 78.
Since a pressure of the high-pressure region 30 and a pressure of
the back pressure chamber 29 can be fully isolated from each other,
it becomes implementable to stably control the pressure on the back
face of the turning scroll 13.
[0048] In a portion 12c of the end plate 12a between laps 12b of
the stationary scroll 12, a recess portion 12d is formed. Further,
an in-lap oil feed path 55 is formed in the turning scroll 13. The
in-lap oil feed path 55 is communicated with the back pressure
chamber 29 via one opening 55a. Then, the back pressure chamber 29
is communicated with the oil storage section 20 via a lead-in path
54 provided on the back face side of the turning scroll 13 and the
oil feed hole 26 provided in the shaft 4. Meanwhile, the other
opening 55b of the in-lap oil feed path 55 is formed in a top face
of the lap 13a that makes sliding contact with the end plate 12a of
the stationary scroll 12. The opening 55b of the in-lap oil feed
path 55 is moved relative to the stationary scroll 12 by the
turning motion of the turning scroll 13 so as to draw a circular
turning locus as shown by broken line in FIG. 3.
[0049] FIG. 3 shows a plurality of states of the turning scroll 13
engaged with the stationary scroll 12, more specifically, states of
the turning scroll 13 individually differing by steps of 90.degree.
from one another. As shown in FIG. 3, the compression chamber 15
formed by the stationary scroll 12 and the turning scroll 13
includes a first compression chamber 15a formed outside the lap 13a
of the turning scroll 13, and a second compression chamber 15b
formed inside the lap 13a. The first compression chamber 15a and
the second compression chamber 15b are moved each by turning motion
of the turning scroll 13 toward the center while reducing their
capacities. When the refrigerant in the compression chamber 15 has
reached the discharge pressure and moreover the compression chamber
15 and the discharge hole 18 are communicated with each other, the
refrigerant in the compression chamber 15 pushes and opens the lead
valve 19, thus moving into a discharge chamber 31.
[0050] As shown in FIG. 3, the opening 55b of the in-lap oil feed
path 55 and the recess portion 12d formed at the portion 12c of the
end plate 12a of the stationary scroll 12 are intermittently
communicated with each other. As a result of this, the in-lap oil
feed path 55 and the second compression chamber 15b are
intermittently communicated with each other via the recess portion
12d.
[0051] The following description is given by focusing on the second
compression chamber 15b. As shown in FIG. 3(a), when the second
compression chamber 15b formed on the outermost side of the turning
scroll 13 and the suction port 17 are communicated with each other,
introduction of the refrigerant into the second compression chamber
15b is started (start of suction process). Then, as shown in FIG.
3(c), the second compression chamber 15b is closed by turning
motion of the turning scroll 13, so that the refrigerant is
enclosed within the second compression chamber 15b (start of
compression process). Thereafter, as shown in FIG. 3(d), the
opening 55b of the in-lap oil feed path 55 is communicated with the
second compression chamber 15b via the recess portion 12d by
turning motion of the turning scroll 13, and then the oil 6 is fed
from the back pressure chamber 29 via the in-lap oil feed path 55
to the second compression chamber 15b after the refrigerant has
been enclosed therein. In contrast to this, with the opening 55b
and the recess portion 12d not communicated with each other as
shown in FIG. 3(a)-(c), oil is scarcely fed from the back pressure
chamber 29 to the second compression chamber 15b. Thus, by making
the opening 55b of the in-lap oil feed path 55 and the second
compression chamber 15b intermittently communicated with each other
via recess portion 12d of the stationary scroll 12, the oil 6 is
intermittently fed to the second compression chamber 15b via the
in-lap oil feed path 55. It is noted that the reason of feeding the
oil 6 to the second compression chamber 15b will be described
later.
[0052] As described above, according to this Embodiment 1, use of a
single refrigerant of hydrofluoroolefin or a mixed refrigerant
containing the hydrofluoroolefin, being low in ODP and GWP, makes
it possible to suppress is effects on the global environment. Also,
by feeding the oil 6 to the second compression chamber 15b after
the refrigerant has been enclosed therein (compression process),
the temperature of the refrigerant after its compression to a
prescribed pressure becomes lower, as compared with cases where the
oil 6 is fed in the suction process (i.e., in a state of being
communicated with the suction port 17).
[0053] The reason that the refrigerant temperature after the
compression the prescribed pressure is lower in feeding of the oil
6 to the second compression chamber 15b in the compression process
than in feeding of the oil 6 to the second compression chamber 15b
in the suction process is as follows.
[0054] The refrigerant during suction to the second compression
chamber 15b (in the suction process) is the lowest in its
temperature. Feeding a high-temperature oil 6 to such a refrigerant
causes the refrigerant to be strongly heated because of a large
temperature difference between the refrigerant and the oil 6 (as a
result, decomposition of the refrigerant progresses to a large
extent). In contrast to this, the refrigerant under compression has
increased in temperature of the refrigerant itself along with the
compression, having a small temperature difference from the fed oil
6. In a case of the refrigerant further compressed to near the
discharge pressure, the refrigerant temperature becomes higher than
the temperature of the fed oil 6. Accordingly, heating of the
refrigerant by the oil 6 can be suppressed more in the case where
the oil 6 is fed to the second compression chamber 15b after the
refrigerant has been enclosed therein (compression process). Thus,
not by feeding the oil 6 in suction process but by feeding the oil
6 in compression process, heating of the refrigerant can be
suppressed while the sealability of the second compression chamber
15b after the refrigerant has been enclosed therein can be improved
by the oil 6. In addition, desirably, the oil 6 is fed at such a
timing that a temperature difference of the oil 6 from the
refrigerant is as small as possible.
[0055] Further, since the sealability of the second compression
chamber 15b (between the end plate 12a of the stationary scroll 12
and the lap 13b of the turning scroll 13 and between the lap 12b
and the end plate 13a) is improved by the oil 6, re-expansion
heating, i.e. leakage of the refrigerant from the second
compression chamber 15b, can be suppressed.
[0056] As a result, temperature increases of the refrigerant are
suppressed, so that decomposition of the refrigerant is inhibited.
Thus, there can be provided a rotary compressor being excellent in
reliability and durability and having high efficiency with
considerations given to the global environment.
[0057] Further, the oil 6 in the back face of the turning scroll 13
can be fed to the second compression chamber 15b via the in-lap oil
feed path 55 and the recess portion 12d when the turning scroll 13
is in a particular phase (i.e., when the shaft 4 is at a particular
turning angle). That is, the oil 6 can be fed to the second
compression chamber 15b at such an optimum timing and an optimum
quantity that improvement of the sealability of the second
compression chamber 15b as well as suppression of temperature
increases of the refrigerant by feeding of the oil 6 can be
fulfilled effectively. As a result, temperature increases of the
refrigerant due to the feeding of the oil 6 and the re-expansion
heating due to the leakage of the refrigerant can be suppressed
more securely.
[0058] Now the reason of feeding the oil 6 to the second
compression chamber 15b via the in-lap oil feed path 55 is
described below. First, configuration of the laps included in the
stationary scroll 12 and the turning scroll 13 is described. In
this embodiment, the volute shape of the laps of the stationary
scroll and the turning scroll is defined by an involute curve.
Given an involute angle of .theta. and a basic circle radius of a,
an involute curve can be expressed by the following function in the
Cartesian coordinate system:
x=a(cos .theta.+.theta. sin .theta.)
y=a(sin .theta.+.theta. cos .theta.) (Eq. 1)
[0059] A curve expressed by Equation 1 is taken as a reference
curve. Out of two envelope curves drawn by the reference curve as a
result of turning with a turning radius of .epsilon., the outer
envelope curve is expressed by the following function:
x=a(cos(.theta.-.epsilon./a)+.theta. sin(.theta.-.epsilon./a))
y=a(sin(.theta.-.epsilon./a)+.theta. cos(.theta.-.epsilon./a)) (Eq.
2)
[0060] Similarly, the inner envelope curve is expressed by the
following function:
x=a(cos(.theta.+.epsilon./a)+.theta. sin(.theta.+.epsilon./a))
y=a(sin(.theta.+.epsilon./a)+.theta. cos(.theta.+.epsilon./a)) (Eq.
3)
[0061] By defining an outer surface of the lap of either one of the
stationary scroll 12 or the turning scroll 13 with the
above-described function of the reference curve, and by defining an
inner surface of the other lap combined with the above lap by using
the above-described function of the outer envelope curve, it
follows that a plurality of minimum radial clearances on the inner
surface side of the lap 13b of the turning scroll 13 or a plurality
of minimum radial clearances on the outer surface side of the lap
13b of the turning scroll 13, both of which are formed
simultaneously by engagement of the lap of the stationary scroll
and the lap of the turning scroll with each other, become equal to
one another. In this embodiment, an asymmetrical compression
chamber 15 is realized by forming the lap 12b of the stationary
scroll 12 and the lap 13b of the turning scroll 13 so that their
numbers of turns differ from each other, with an aim of enlarging
the capacity of the compression chamber 15.
[0062] Since an asymmetrical compression chamber is formed,
capacity change rate of the second compression chamber 15b formed
on the inner surface side of the lap 13b of the turning scroll 13
is larger than capacity change rate of the first compression
chamber 15a formed on the outer surface side of the lap 13b. The
second compression chamber 15b having the larger capacity change
rate increases in refrigerant pressure more rapidly than the first
compression chamber 15a, resulting in a larger pressure difference
from the lower-pressure side compression chamber 15. Because of
this, leakage of the refrigerant to the lower-pressure side
compression chamber 15 from the second compression chamber 15b by
passing through between the lap and the end plate is more likely to
occur, making it necessary to improve the sealability.
[0063] Therefore, in this Embodiment 1, the in-lap oil feed path 55
and the recess portion 12d are properly provided so that as much
oil 6 as possible is fed to the second compression chamber 15b of
larger capacity change rate. As a result, leakage of the
refrigerant from the second compression chamber 15b to the
lower-pressure side compression chamber 15 is suppressed, so that
the re-expansion heating of the refrigerant in the lower-pressure
side compression chamber 15 is suppressed and moreover pressure
increases due to internal leakage can be suppressed. As a result,
temperature increases of the refrigerant, which is easily
decomposable at high temperatures and which is used for the scroll
compressor of Embodiment 1, can be suppressed.
[0064] Furthermore, it is also allowable that another
compression-chamber oil feed path for feeding the oil 6 to the
first compression chamber 15a (a second compression-chamber oil
feed path different from the first compression-chamber oil feed
path) is provided so that a smaller quantity of oil 6 than that of
oil 6 intermittently fed to the second compression chamber 15b is
fed to the first compression chamber 15a via the another
compression-chamber oil feed path. As such another
compression-chamber oil feed path, for example, a
compression-chamber oil feed path 57 shown in FIG. 2 is provided.
The compression-chamber oil feed path 57 is formed in the turning
scroll 13. One opening of the compression-chamber oil feed path 57
is formed in the top face of the lap 13b. The other opening is
communicated with the oil storage section 20 via the lead-in path
54 provided in the back face of the turning scroll 13, the oil feed
hole 26 provided in the shaft 4 and the like. As a result of this,
a small quantity of oil 6 can be fed through the clearance between
the end plate 12a of the stationary scroll 12 and the top face of
the lap 13b of the turning scroll 13.
[0065] In this case also, re-expansion heating of the refrigerant
can be suppressed and moreover pressure increases due to internal
leakage can be suppressed. Further, since the feed rate of the oil
6 to the second compression chamber 15b of higher capacity change
rate is larger than the feed rate of the oil 6 to the first
compression chamber 15a, the sealability of the compression
chamber, which is liable to leakage of the refrigerant because of a
large pressure difference from the lower-pressure side compression
chamber 15, can be improved by an optimum quantity of oil. As a
result of this, heating of the refrigerant due to excessive
refrigerating machine oil, which could be caused by feeding of
excessive quantities of refrigerating machine oil, can also be
suppressed.
[0066] Besides, with respect to the quantity of oil 6 fed to the
second compression chamber 15b, it is also allowable that a
quantity of oil smaller than the quantity of oil fed after
enclosing of the refrigerant (after closure of the second
compression chamber 15b) is fed before the enclosing of the
refrigerant (before the second compression chamber 15b starts to be
closed) or during the enclosing of the refrigerant (during a period
from a start of closure of the second compression chamber 15b until
its complete closure). That is, only if most part of the necessary
quantity of oil 6 is fed after the enclosing of the refrigerant,
temperature increases of the refrigerant, i.e. decomposition of the
refrigerant, can be suppressed.
Embodiment 2
[0067] FIG. 4 is a partly enlarged sectional view of a compression
mechanism of a scroll compressor according to Embodiment 2 of the
invention. FIG. 5 is a view showing a plurality of states of a
turning scroll. Component members other than a compression-chamber
oil feed path 56 are similar to those of above-described Embodiment
1. In FIGS. 4 and 5, the same component members as in FIGS. 2 and 3
are designated by the same reference signs. Also, the following
description is made about the compression-chamber oil feed path 56
alone, and description of the other component members is
omitted.
[0068] As shown in FIG. 4, in the scroll compressor of this
Embodiment 2, a compression-chamber oil feed path 56 is formed in
the end plate 13a of the turning scroll 13. The compression-chamber
oil feed path 56 communicates the back pressure chamber 29 and the
first compression chamber 15a formed on the outer surface side of
the lap 13b of the turning scroll 13 with each other. While the
turning scroll 13 is in a state shown in FIG. 5(b), the
compression-chamber oil feed path 56 is communicated with the first
compression chamber 15a so that the oil 6 is fed to the first
compression chamber 15a. On the other hand, while the turning
scroll 13 is in a state shown in FIG. 5(a), 5(c) or 5(d), the
compression-chamber oil feed path 56 is closed by the end plate 12a
of the stationary scroll 12, so that the oil 6 is not fed to the
first compression chamber 15a. In a scroll compressor in which the
capacity of the compression chamber reduces along with movement
from outer periphery toward center, a compression chamber located
on the outer side is larger in capacity than a compression chamber
located on the central side. Therefore, with respect to a leak
length (in other words, necessary seal length), which is a length
of a portion through which the refrigerant leaks from a
high-pressure side compression chamber of smaller capacity to a
low-pressure side compression chamber of larger capacity, the
length of the first compression chamber 15a formed on the outer
side of the lap 13b of the turning scroll 13 is longer than the
length of the second compression chamber 15b formed on the inner
side. Accordingly, the oil 6 is fed to the first compression
chamber 15a of longer leak length via the compression-chamber oil
feed path 56 in a quantity larger than the quantity of oil 6 fed to
the second compression chamber 15b, by which the first compression
chamber 15a of longer leak length is sealed enough. As a result of
this, temperature increases of the refrigerant, which is easily
decomposable at high temperatures, are suppressed.
[0069] According to this Embodiment 2, re-expansion heating of the
refrigerant and pressure increases due to internal leakage can be
suppressed, and moreover making the feed rate of oil 6 to the first
compression chamber 15a of longer leak length larger than the feed
rate of oil 6 to the second compression chamber 15b makes it
possible to optimize the feed rate of oil 6 for improvement of the
sealability in correspondence to the length of the leakage portion
of the compression chamber. As a result, heating of the refrigerant
due to excessive refrigerating machine oil, which could be caused
by feeding of excessive quantities of refrigerating machine oil,
can also be suppressed.
Embodiment 3
[0070] FIG. 6 is a longitudinal sectional view of a rotary
compressor according to Embodiment 3 of the invention. FIG. 7 is an
enlarged sectional view of a compression mechanism of the rotary
compressor. FIG. 8 is an assembly structural view of the
compression mechanism of the rotary compressor. FIG. 9 is a view
showing a plurality of states of the compression mechanism of the
rotary compressor. In the rotary compressor, as shown in FIGS. 6
and 7, an electric motor 102 and a compression mechanism 103, being
coupled together via a crankshaft 131, are housed within the closed
container 101. The compression mechanism 103 includes: a cylinder
130; a suction chamber 149 and a compression chamber 139 defined by
an end plate 134 of an upper bearing 134a and an end plate 135 of a
lower bearing 135a for closing both end faces of the cylinder 130;
a piston 132 placed within the cylinder 130; and a vane 133 which
is in contact with an outer peripheral surface of the piston 132 to
divide the cylinder 130 into the suction chamber 149 and the
compression chamber 139. The piston 132 is fitted to an eccentric
portion 131a of the crankshaft 131 supported by the upper bearing
134a and the lower bearing 135a so as to be eccentrically rotated
by the crankshaft 131. The vane 133 is so constructed as to make
reciprocating motion toward the piston 132 in correspondence to
eccentric rotation of the piston 132 so as to maintain the contact
with the outer peripheral surface of the eccentrically rotating
piston 132.
[0071] In the crankshaft 131, an oil hole 141 is formed along a
center axis for drawing up oil from the oil storage section 20. Oil
feed holes 142, 143 communicated with the oil hole 141 are provided
at portions of the crankshaft 131 facing the upper bearing 134a and
the lower bearing 135a, respectively. Also, an oil feed hole 144
communicated with the oil hole 141 and an oil groove 145
communicated with the oil feed hole 144 are formed at portions of
the eccentric portion 131a of the crankshaft 131 facing the piston
132.
[0072] Meanwhile, a suction port 140 for sucking a gaseous
refrigerant into the suction chamber 149 is formed in the cylinder
130. As a sliding-contact portion of the piston 132 which is in
sliding contact with an inner peripheral surface of the cylinder
130 passes through the suction port 140 so as to be separated from
the suction port 140, the suction chamber 149 expands gradually,
causing the refrigerant to be sucked into the suction chamber 149
through the suction port 140. In the upper bearing 134a is a
discharge port 138 opened for discharging out the refrigerant from
the compression chamber 139. The discharge port 138 is formed as a
hole having a circular cross section extending through the upper
bearing 134a. In the top face of the discharge port 138, a delivery
valve 136 which opens upon reception of a more than specified
pressure, and a cap muffler 137 for covering the delivery valve
136, are provided.
[0073] As the sliding-contact portion of the piston 132 in sliding
contact with the inner peripheral surface of the cylinder 130
approaches the discharge port 138 more and more, the compression
chamber 139 is reduced gradually. When the refrigerant within the
compression chamber 139 is compressed to a specified pressure or
more, the delivery valve 136 is opened. When the delivery valve 136
is opened, the refrigerant flows out through the discharge port 138
so as to be discharged out into the closed container 101 by the cap
muffler 137.
[0074] On the other hand, a space 146 surrounded by the eccentric
portion 131a of the crankshaft 131, the end plate 134 of the upper
bearing 134a and the inner peripheral surface of the piston 132,
and a space 147 surrounded by the eccentric portion 131a of the
crankshaft 131, the end plate 135 of the lower bearing 135a and the
inner peripheral surface of the piston 132, are formed, it is
leaked into those spaces 146, 147 from the oil hole 141 via the oil
feed holes 142, 143. Pressures of these spaces 146, 147, nearly
normally higher than the pressure inside the compression chamber
139, are generally equal to the discharge pressure.
[0075] Also, the height of the cylinder 130 is set slightly larger
than the height of the piston 132 so that the piston 132 is enabled
to make sliding contact inside the cylinder 130. As a result, there
are clearances between the end face of the piston 132 and the end
plate 134 of the upper bearing 134a as well as the end plate 135 of
the lower bearing 135a. Oil in the spaces 146, 147 leaks via these
clearances into the compression chamber 139.
[0076] In the rotary compressor constructed as described above, as
shown hi FIG. 8, a recess-shaped compression-chamber oil feed path
155 is provided in the end plate 135 of the lower bearing 135a.
FIG. 9 shows a positional relationship between the piston 132 and
the oil feed path 155, as viewed in a center-axis direction of the
crankshaft 131. As shown in left, lower part of FIG. 9, oil is fed
to the compression chamber 139 at range of a crank angle of the
crankshaft 131 that an inlet 155a of the compression-chamber oil
feed path 155 and the inside of the piston 132 are communicated
with each other as well as an outlet 155b of the oil feed path 155
and the compression chamber 139 are communicated with each other.
In this case, by providing the compression-chamber oil feed path
155 in such a manner that the inlet 155a and the outlet 155b differ
from each other in terms of angular position with respect to a
crankshaft center, it becomes achievable to determine such a crank
angle that oil is allowed to flow into the inlet 155a. As a result,
the degree of freedom for the position of the outlet 155b is
increased. Thus, it becomes possible to provide the outlet 155b of
the compression-chamber oil feed path 155 near a
refrigerant-leaking place.
[0077] Also, as shown in left, lower part of FIG. 9, by providing
the outlet 155b of the oil feed path 155 at a position near a
contact point between the piston 132 and the cylinder 130 in the
compression chamber 139, leakage of the refrigerant through between
the piston 132 and the cylinder 130 can be suppressed with a
necessary, minimum quantity of oil. Thus, temperature increases of
the refrigerant, which is easily decomposable at high temperatures,
are suppressed.
[0078] According to this Embodiment 3, with use of a refrigerant
being low in both ODP and GWP, effects on the global environment
can be reduced. Also, by feeding the oil to the compression chamber
139 after the refrigerant has been enclosed therein, re-expansion
heating of the refrigerant is suppressed and moreover heating of
the refrigerant by the refrigerating machine oil is suppressed, as
compared with cases in which the refrigerating machine oil is fed
in the suction process (before the refrigerant is enclosed in the
compression chamber). As a result, decomposition of the refrigerant
is inhibited.
[0079] Hereinabove, rotary compressors of Embodiments 1 to 3 have
been described. In the rotary compressors of Embodiments 1 to 3, a
single refrigerant of hydrofluoroolefin having a double bond of
carbon or a mixed refrigerant containing the hydrofluoroolefin is
used. As this mixed refrigerant, a refrigerant resulting from
mixing hydrofluoroolefin with hydrofluorocarbon having no double
bond of carbon may also be used.
[0080] Further, a mixed refrigerant of tetrafluoropropene
(HFO1234yf or HFO1234ze) or trifluoropropene (HFO1243zf), which is
a kind of hydrofluoroolefin, and difluoromethane (HFC32), which is
a kind of hydrofluorocarbon, may also be used.
[0081] Further, a mixed refrigerant of tetrafluoropropene
(HFO1234yf or HFO1234ze) or trifluoropropene (HFO1243zf), which is
a kind of hydrofluoroolefin, and pentafluoroethane (HFC125), which
is a kind of hydrofluorocarbon, may also be used.
[0082] Still further, a mixed refrigerant composed of three
components resulting from mixing together tetrafluoropropene
(HFO1234yf or HFO1234ze) or trifluoropropene (HFO1243zf), which is
a kind of hydrofluoroolefin, pentafluoroethane (HFC125), which is a
kind of hydrofluorocarbon, and difluoromethane (HFC32), may also be
used.
[0083] Preferably, those mixed refrigerants described above are
blended in such a two-component or three-component mixing that the
GWP falls within a range of 5 to 750, desirably 5 to 350.
[0084] Further, preferably usable as the refrigerating machine oil
to be used for the rotary compressor according to the invention are
(1) polyoxyalkylene glycols, (2) polyvinyl ethers, (3)
poly(oxy)alkylene glycol or copolymers of its monoether and
polyvinyl ether, or (4) synthetic oils containing an oxygenated
compound of polyol esters and polycarbonates, (5) synthetic oils
containing alkylbenzenes as a principal ingredient, or (6)
synthetic oils containing .alpha.-olefins as a principal
ingredient.
[0085] Although the present invention has been fully described in
connection with the preferred embodiments thereof with reference to
the accompanying drawings, it is to be noted that various changes
and modifications are apparent to those skilled in the art. Such
Changes and modifications are to be understood as included within
the scope of the present invention as defined by the appended
claims unless they depart therefrom.
[0086] The entire disclosure of Japanese Patent Application No.
2010-214877 filed on Sep. 27, 2010, including specification,
claims, drawings, and summary are incorporated herein by reference
in its entirety.
INDUSTRIAL APPLICABILITY
[0087] As described above, according to the present invention, even
with use of a single refrigerant of hydrofluoroolefin having a
double bond of carbon or a mixed refrigerant containing the
hydrofluoroolefin, there can be realized a rotary compressor of
high reliability, high durability and high efficiency. Therefore,
the invention is applicable also to use in air conditioners,
heat-pump water heaters, refrigerator-freezers, dehumidifiers or
the like including rotary compressors.
REFERENCE SIGNS LIST
[0088] 12 stationary scroll [0089] 12a end plate [0090] 12b lap
[0091] 12d recess portion [0092] 13 turning scroll [0093] 13a end
plate [0094] 13b lap [0095] 14 automatic constraint mechanism
[0096] 15 compression chamber [0097] 15a first compression chamber
[0098] 15b second compression chamber [0099] 17 suction port [0100]
18 discharge hole [0101] 19 lead valve [0102] 20 oil storage
section [0103] 29 back pressure chamber [0104] 30 high-pressure
region [0105] 55 in-lap oil feed path [0106] 56 compression-chamber
oil feed path [0107] 130 cylinder [0108] 131 crankshaft [0109] 133
vane [0110] 134a upper bearing [0111] 135a lower bearing [0112] 139
compression chamber [0113] 141 oil hole [0114] 155
compression-chamber oil feed path
* * * * *