U.S. patent application number 14/008231 was filed with the patent office on 2014-01-16 for scroll compressor.
The applicant listed for this patent is Katsumi Katou, Youhei Nishide, Takashi Uekawa. Invention is credited to Katsumi Katou, Youhei Nishide, Takashi Uekawa.
Application Number | 20140017108 14/008231 |
Document ID | / |
Family ID | 46930208 |
Filed Date | 2014-01-16 |
United States Patent
Application |
20140017108 |
Kind Code |
A1 |
Uekawa; Takashi ; et
al. |
January 16, 2014 |
SCROLL COMPRESSOR
Abstract
A scroll compressor (10) includes a bearing oil supply passage
(70) configured to supply a refrigeration oil from an oil reservoir
(18) located in a casing (15) to a bearing of a driving shaft (60).
An oil groove (80) which communicates only with the oil reservoir
(18) in the casing (15) through a connection passage (86) and a
capillary tube (87) is formed on a thrust sliding surface (35) of a
fixed scroll (30). Since the bearing oil supply passage (70) is not
in communication with the oil groove (80), even when an orbiting
scroll (40) is tilted and a pressure of the oil groove (80)
decreases, a pressure of the bearing oil supply passage (70) does
not decrease, and accordingly, the refrigeration oil is supplied
from the bearing oil supply passage (70) to the bearing of the
driving shaft (60).
Inventors: |
Uekawa; Takashi; (Osaka,
JP) ; Nishide; Youhei; (Osaka, JP) ; Katou;
Katsumi; (Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Uekawa; Takashi
Nishide; Youhei
Katou; Katsumi |
Osaka
Osaka
Osaka |
|
JP
JP
JP |
|
|
Family ID: |
46930208 |
Appl. No.: |
14/008231 |
Filed: |
March 28, 2012 |
PCT Filed: |
March 28, 2012 |
PCT NO: |
PCT/JP2012/002161 |
371 Date: |
September 27, 2013 |
Current U.S.
Class: |
418/55.1 |
Current CPC
Class: |
F04C 23/008 20130101;
F04C 18/0253 20130101; F05C 2253/22 20130101; F04C 29/025 20130101;
F04C 18/0215 20130101; F04C 18/0207 20130101; F04C 29/028 20130101;
F04C 2240/806 20130101 |
Class at
Publication: |
418/55.1 |
International
Class: |
F04C 18/02 20060101
F04C018/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 29, 2011 |
JP |
2011-73396 |
Claims
1. A scroll compressor comprising: a casing; a compression
mechanism housed in the casing, the compression mechanism including
a fixed scroll and an orbiting scroll; a driving shaft housed in
the casing, the drive shaft being engaged with the orbiting scroll;
a bearing oil supply passage configured to supply the lubricating
oil from an oil reservoir located in the casing to a bearing
location in the compression mechanism, the bearing location being
disposed with the driving shaft; and a groove communication
passage, the compression mechanism being configured to discharge a
compressed fluid into the casing and to generate a pressing force
pressing the orbiting scroll against the fixed scroll, the orbiting
scroll having an end plate with a thrust sliding surface and the
fixed scroll having a thrust sliding surface, the thrust sliding
surfaces of the fixed scroll and the orbiting scroll being in
sliding contact with each other, one of the thrust sliding surfaces
of the orbiting scroll and the fixed scroll includes an oil groove
arranged such that a lubricating oil flows into the oil groove, the
bearing oil supply passage not being in communication with he oil
groove, and the groove communication passage connecting the oil
groove to the oil reservoir in the casing.
2. The scroll compressor of claim 1, wherein the bearing oil supply
passage is provided with an oil supply pump driven by the driving
shaft and configured to suck the lubricating oil from the oil
reservoir in the casing and to discharge the lubricating oil, and
the groove communication passage is configured such that the
lubricating oil is caused to flow through the groove communication
passage only by a pressure difference between the oil reservoir and
the oil groove.
3. The scroll compressor of claim 2, wherein the groove
communication passage is provided with at least one throttle
configured to control a flow rate of the lubricating oil.
4. The scroll compressor of claim 3, wherein the throttle is at
least one rod member disposed in the groove communication passage,
the throttle includes a spiral groove on an outer circumference,
and the spiral groove is configured to allow the lubricating oil to
flow therethrough.
5. The scroll compressor of claim 4, wherein the at least one rod
member includes a plurality of rod members, and the plurality of
rod members are disposed in a plurality of locations of the groove
communication passage.
6. The scroll compressor of claim 5, further comprising: a bearing
separate from the compression mechanism and supporting the driving
shaft in a rotatable manner, the bearing including a first
communicating path therein and the fixed scroll including a second
communicating path therein, the first and second communicating
paths forming parts of the groove communication passage, and each
of the first and second communicating paths being provided with an
associated one of the rod members.
7. The scroll compressor of claim 1, further comprising: a motor
configured to drive and rotate the driving shaft; and a connection
pipe provided between the casing and the motor, the connection pipe
forming part of the groove communication passage, the connection
pipe being one of a resin pipe made of a resin material, and a
metal pipe having an outer circumferential surface coated with a
resin material.
8. The scroll compressor of claim 1, wherein a lubricating oil
inlet of the groove communication passage is located higher than a
suction inlet of the bearing oil supply passage.
9. The scroll compressor of claim 2, further comprising: a motor
configured to drive and rotate the driving shaft; and a connection
pipe provided between the casing and the motor, the connection pipe
forming part of the groove communication passage, the connection
pipe being one of a resin pipe made of a resin material, and a
metal pipe having an outer circumferential surface coated with a
resin material.
10. The scroll compressor of claim 2, wherein a lubricating oil
inlet of the groove communication passage is located higher than a
suction inlet of the bearing oil supply passage.
11. The scroll compressor of claim 3, further comprising: a motor
configured to drive and rotate the driving shaft; and a connection
pipe provided between the casing and the motor, the connection pipe
forming part of the groove communication passage, the connection
pipe being one of a resin pipe made of a resin material, and a
metal pipe having an outer circumferential surface coated with a
resin material.
12. The scroll compressor of claim 4, further comprising: a motor
configured to drive and rotate the driving shaft; and a connection
pipe provided between the casing and the motor, the connection pipe
forming part of the groove communication passage, the connection
pipe being one of a resin pipe made of a resin material, and a
metal pipe having an outer circumferential surface coated with a
resin material.
13. The scroll compressor of claim 4, wherein a lubricating oil
inlet of the groove communication passage is located higher than a
suction inlet of the bearing oil supply passage.
14. The scroll compressor of claim 5, further comprising: a motor
configured to drive and rotate the driving shaft; and a connection
pipe provided between the casing and the motor, the connection pipe
forming part of the groove communication passage, the connection
pipe being one of a resin pipe made of a resin material, and a
metal pipe having an outer circumferential surface coated with a
resin material.
15. The scroll compressor of claim 5, wherein a lubricating oil
inlet of the groove communication passage is located higher than a
suction inlet of the bearing oil supply passage.
16. The scroll compressor of claim 6, further comprising: a motor
configured to drive and rotate the driving shaft; and a connection
pipe provided between the casing and the motor, the connection pipe
forming part, of the groove communication passage, the connection
pipe being one of a resin pipe made of a resin material, and a
metal pipe having an outer circumferential surface coated with a
resin material.
17. The scroll compressor of claim 6, wherein a lubricating oil
inlet of the groove communication passage is located higher than a
suction inlet of the bearing oil supply passage.
18. The scroll compressor of claim 12, wherein a lubricating oil
inlet of the groove communication passage is located higher than a
suction inlet of the bearing oil supply passage.
19. The scroll compressor of claim 14, wherein a lubricating oil
inlet of the groove communication passage is located higher than a
suction inlet of the bearing oil supply passage.
20. The scroll compressor of claim 16, wherein a lubricating oil
inlet of the groove communication passage is located higher than a
suction inlet of the bearing oil supply passage.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to measures to improve
reliability of scroll compressors.
BACKGROUND ART
[0002] Conventionally, scroll compressors have been widely used to
compress, e.g., refrigerants or air. For example, Patent Document 1
discloses a hermetic scroll compressor. Here, the structure of the
scroll compressor (500) disclosed in Patent Document 1 is described
with reference to FIG. 9.
[0003] The scroll compressor (500) includes a vertically oriented
cylindrical casing (510) in which a compression mechanism (520) and
a motor (515) are housed. The compression mechanism (520) is
disposed above the motor (515), and a driving shaft (550) connects
the compression mechanism (520) to the motor (515).
[0004] The compression mechanism (520) includes a fixed scroll
(525), an orbiting scroll (530), and housing (540). The orbiting
scroll (530) has an end plate (531), a lap (532) projecting from
the front side of the end plate (531), and a cylindrical portion
(533) projecting from the backside of the end plate (531). In the
compression mechanism (520), the lap (532) of the orbiting scroll
(530) is engaged with a lap (526) of the fixed scroll (525),
thereby forming compression chambers (521). The end plate (531) of
the orbiting scroll (530) has a thrust sliding surface (536) which
is in sliding contact with a thrust sliding surface (527) of the
fixed scroll (525). The driving shaft (550) has an eccentric
portion (551) inserted in the cylindrical portion (533) of the
orbiting scroll (530). When the driving shaft (550) rotates, the
orbiting scroll (530) performs orbital motion and a refrigerant
sucked in the compression chambers (521) is compressed,
[0005] In the scroll compressor (500), the driving shaft (550)
includes an oil supply passage (555) formed therein. A lubricating
oil having flowed from a bottom portion of the casing (510) into
the oil supply passage (555) is supplied to a bearing portion
through a first branch passage (556) and a second branch passage
(557). Part of the lubricating oil flowing through the oil supply
passage (555) comes out of a terminal end of the oil supply passage
(555) which opens at an upper end of the eccentric portion
(551).
[0006] The pressure of the refrigerant present in the compression
chambers (521) acts on the front side of the end plate (531) of the
orbiting scroll (530). Accordingly, an increase in the pressure of
the refrigerant in the compression chambers (521) causes the
orbiting scroll (530) to be pushed down, and thereby reduces air
tightness of the compression chambers (521).
[0007] On the other hand, the scroll compressor (500) includes a
seal ring (541) provided between the housing (540) and the orbiting
scroll (530). The pressure present inside the seal ring (541) is
substantially equal to the pressure of the lubricating oil having
flowed out from the terminal end of the oil supply passage (555)
(consequently, substantially equal to the pressure of the
refrigerant discharged from the compression mechanism (520)).
Accordingly, the orbiting scroll (530) is upwardly pushed by the
pressure acting on the backside of the end plate (531). The
orbiting scroll (530) is consequently pressed against the fixed
scroll (525), and the air tightness of the compression chambers
(521) is ensured.
[0008] However, the force pressing the orbiting scroll (530)
against the fixed scroll (525) sometimes becomes too strong. In
such a case, the friction force generated between the thrust
sliding surface (536) of the orbiting scroll (530) and the thrust
sliding surface (527) of the fixed scroll (525) becomes strong,
resulting in an increase in power consumption of the motor
(515).
[0009] On the other hand, the scroll compressor (500) includes an
oil groove (534) and a communication passage (535) which are formed
on the end plate (531) of the orbiting scroll (530). The oil groove
(534) is a groove which opens on the thrust sliding surface (536)
of the end plate (531) and surrounds the lap (532).
[0010] The oil groove (534) communicates with the inner space of
the cylindrical portion (533) through the communication passage
(535). Accordingly, the pressure inside the oil groove (534) is
substantially equal to the pressure of the lubricating oil having
flowed out from the terminal end of the oil supply passage (555).
The pressure of the compression chamber (521) adjacent to the oil
groove (534) is approximate to the pressure of the low-pressure
refrigerant sucked in the compression chamber (521) and lower than
the pressure of the oil groove (534). Accordingly, a pressure
difference between the oil groove (534) and the compression chamber
(521) causes a sufficient amount of the lubricating oil to be
supplied to the thrust sliding surfaces (527, 536). Consequently,
the friction force between the thrust sliding surface (536) of the
orbiting scroll (530) and the thrust sliding surface (527) of the
fixed scroll (525) becomes weak, and accordingly, the power
consumption of the motor (515) is kept low.
CITATION LIST
Patent Document
[0011] PATENT DOCUMENT 1: Japanese Patent No. 3731068
SUMMARY OF THE INVENTION
Technical Problem
[0012] In the orbiting scroll (530) of the scroll compressor (500),
the internal pressure of the compression chambers (521) acts on the
lap (532) projecting from the front side of the end plate (531),
and a load from the driving shaft (550) acts on the cylindrical
portion (533) projecting from the backside of the end plate (531).
The line of action of the gas pressure acting on the lap (532) and
the line of action of the load acting on the cylindrical portion
(533) intersect the axial direction of the orbiting scroll (530) at
right angles but do not intersect each other. Accordingly, a moment
acts on the orbiting scroll (530) in a direction tilting the
orbiting scroll (530).
[0013] If the pressure acting on the backside of the end plate
(531) (specifically, the pressure inside the seal ring (541)) is
sufficiently high, the orbiting scroll (530) is strongly pressed
against the fixed scroll (525), and accordingly, the orbiting
scroll (530) is not tilted even by the moment acting thereon.
However, in an operational state where the pressure acting on the
backside of the end plate (531) is insufficiently high (for
example, in an operational state where the pressure of the
refrigerant discharged from the compression mechanism (520) is very
low), the orbiting scroll (530) is sometimes tilted, resulting in
an increase in the clearance between the thrust sliding surface
(536) of the orbiting scroll (530) and the thrust sliding surface
(527) of the fixed scroll (525). In the scroll compressor (500)
shown in FIG. 9, the increase in the clearance between the thrust
sliding surfaces (527, 536) may disadvantageously cause the
pressure in the oil groove (534) to drop abruptly.
[0014] In the conventional scroll compressor (500) shown in FIG. 9,
the oil groove (534) communicates with the bearing portion of the
compression mechanism (520) through the communication passage (535)
and the oil supply passage (555). Therefore, when the orbiting
scroll (530) is tilted and the pressure in the oil groove (534)
abruptly drops, the pressure of the oil supply passage (555)
communicating with the oil groove (534) decreases, and accordingly,
the lubricating oil may disadvantageously flow backward from the
bearing portion to the oil supply passage (555) through the branch
passages (556, 557). This back-flow of the lubricating oil from the
bearing portion to the oil supply passage (555) may cause a
shortage of lubrication in the bearing portion and troubles such as
seizure.
[0015] It is therefore an object of the present disclosure to
improve reliability of scroll compressors.
Solution to the Problem
[0016] A first aspect of the present disclosure relates to a scroll
compressor including: a casing (15); a compression mechanism (20)
housed in the casing (15) and including a fixed scroll (30) and an
orbiting scroll (40); and a driving shaft (60) housed in the casing
(15) and engaged with the orbiting scroll (40), in which the
compression mechanism (20) is configured to discharge a compressed
fluid into the casing (15) and to generate a pressing force which
presses the orbiting scroll (40) against the fixed scroll (30).
According to the first aspect, an end plate (41) of the orbiting
scroll (40) and the fixed scroll (30) respectively include a thrust
sliding surface (45) and a thrust sliding surface (35) which are in
sliding contact with each other, the thrust sliding surface (45) of
the orbiting scroll (40) or the thrust sliding surface (35) of the
fixed scroll (30) includes an oil groove (80) into which a
lubricating oil flows, and the scroll compressor is provided with a
bearing oil supply passage (70) which is not in communication with
the oil groove (80) and is configured to supply the lubricating oil
in an oil reservoir (18) located in the casing (15) to a bearing
provided in the compression mechanism (20) for the driving shaft
(60), and a groove communication passage (85) which connects the
oil groove (80) to the oil reservoir (18) in the casing (15).
[0017] According to the first aspect of the present disclosure,
when the driving shaft (60) drives the orbiting scroll (40), the
fluid is sucked into the compression mechanism (20) to be
compressed therein. The compression mechanism (20) then discharges
the compressed fluid into the casing (15). Accordingly, the
lubricating oil stored in the casing (15) has a pressure which is
substantially equal to a pressure of the fluid discharged from the
compression mechanism (20). The lubricating oil in the casing (15)
passes through the bearing oil supply passage (70) to be supplied
to the bearing in the compression mechanism (20).
[0018] In the compression mechanism (20) of the first aspect, the
orbiting scroll (40) is pressed against the fixed scroll (30) in
order to ensure air tightness of compression chambers. Further, the
thrust sliding surface (45) of the orbiting scroll (40) slides on
the thrust sliding surface (35) of the fixed scroll (30). In the
compression mechanism (20), the thrust sliding surface (45) or the
thrust sliding surface (35) includes the oil groove (80) formed
thereon. The oil groove (80) communicates with the oil reservoir
(18) in the casing (15) through the groove communication passage
(85). Accordingly, the pressure of the lubricating oil in the oil
groove (80) becomes substantially equal to the pressure of the
lubricating oil stored in the casing (15). The lubricating oil
having flowed from the oil reservoir (18) into the oil groove (80)
through the groove communication passage (85) is supplied to the
thrust sliding surface (45) and the thrust sliding surface
(35).
[0019] In the compression mechanism (20) of the first aspect, the
orbiting scroll (40) may be sometimes tilted. In such a case, a
clearance between the thrust sliding surface (45) and the thrust
sliding surface (35) increases, and consequently, the pressure of
the oil groove (80) may abruptly drop. On the other hand, in the
first aspect of the present disclosure, since the bearing oil
supply passage (70) is not in communication with the oil groove
(80), the abrupt pressure drop of the oil groove (80) does not
cause the pressure of the bearing oil supply passage (70) to
change.
[0020] A second aspect of the present disclosure relates to the
scroll compressor of the first aspect, wherein the bearing oil
supply passage (70) is provided with an oil supply pump (75) which
is driven by the driving shaft (60) and configured to suck the
lubricating oil from the oil reservoir (18) in the casing (15) and
to discharge the lubricating oil, and the groove communication
passage (85) is configured such that the lubricating oil is caused
to flow through the groove communication passage (85) only by a
pressure difference between the oil reservoir (18) in the casing
(15) and the oil groove (80).
[0021] According to the second aspect, when the orbiting scroll
(40) is tilted and the pressure of the oil groove (80) decreases
during operation of the compression mechanism (20), the lubricating
oil in the oil reservoir (18) is caused to flow through the groove
communication passage (85) toward the oil groove (80) by the
pressure difference between the oil reservoir (18) in the casing
(15) and the oil groove (80). On the other hand, the bearing oil
supply passage (70) is provided with the oil supply pump (75). The
oil supply pump (75) is driven by the driving shaft (60), sucks the
lubricating oil from the oil reservoir (18) in the casing (15), and
discharges the lubricating oil. The lubricating oil discharged by
the oil supply pump (75) is supplied to the bearing in the
compression mechanism (20).
[0022] A third aspect of the present disclosure relates to the
scroll compressor of the second aspect, wherein the groove
communication passage (85) is provided with at least one throttle
for controlling a flow rate of the lubricating oil.
[0023] When the orbiting scroll (40) is tilted during operation of
the compression mechanism (20), the clearance between the thrust
sliding surface (45) and the thrust sliding surface (35) increases.
Consequently, the lubricating oil easily flows out from the oil
groove (80), and the flow rate of the lubricating oil in the groove
communication passage (85) may become excessively high.
[0024] To address this problem, the groove communication passage
(85) of the third aspect is provided with the throttle.
Accordingly, even in a state where the clearance between the thrust
sliding surface (45) and the thrust sliding surface (35) has
increased, the throttle controls the flow rate of the lubricating
oil in the groove communication passage (85).
[0025] A fourth aspect of the present disclosure relates to the
scroll compressor of the third aspect, wherein the throttle is at
least one rod member (89) which is disposed in the groove
communication passage (85) and includes, on its outer
circumference, a spiral groove (89e) through which the lubricating
oil is allowed to flow.
[0026] According to the fourth aspect, the rod member (89) having
the spiral groove (89e) is disposed in the groove communication
passage (85), thereby forming a narrow spiral channel on the outer
circumference of the rod member (89) disposed in the groove
communication passage (85). The narrow spiral channel on the outer
circumference of the rod member (89) controls the flow rate of the
lubricating oil having flowed o the groove communication passage
(85).
[0027] A fifth aspect of the present disclosure relate to the
scroll compressor of the fourth aspect, wherein the at least one
rod member (89) includes a plurality of rod members (89), and the
plurality of rod members (89) are disposed in a plurality of
locations of the groove communication passage (85).
[0028] According to the fifth aspect, the rod members (89) serving
as the throttles are disposed in the plurality of locations in the
groove communication passage (85). If the groove communication
passage (85) was provided with only one rod member (89), the rod
member (89) provided in the passage (85) would need to be a long
one because the narrow channel would need to be long to some extent
in order to control the flow rate of the lubricating oil
sufficiently. On the other hand, providing the plurality of rod
members (89) in the plurality of locations in the groove
communication passage (85) as described above results in that the
narrow channels have a large length in total although each of the
rod members (89) is short.
[0029] A sixth aspect of the present disclosure elate to the scroll
compressor of the fifth aspect, further including a bearing (55)
which is provided separately from the compression mechanism (20)
and supports the driving shaft (60) in a rotatable manner, wherein
the bearing (55) and the fixed scroll (30) respectively include
therein a communicating path (83) and another communicating path
(81) which form part of the groove communication passage (85), and
each of the communicating paths (83, 81) is provided with an
associated one of the rod members (89).
[0030] According to the sixth aspect, the bearing (55) and the
fixed scroll (30) respectively include therein the communicating
path (83) and the communicating path (81) which form part of the
groove communication passage (85), and each of the communicating
paths(83, 81) is provided with the associated one of the rod
members (89) serving as the throttles. If any one of the bearing
(55) and the fixed scroll (30) was provided with one of the rod
members (89), the narrow channel would need to be long to some
extent to control the flow rate of the lubricating nil
sufficiently, and the rod member (89) and the communicating path
where the rod member (89) is disposed would need to be long.
However, since both of the bearing (55) and the fixed scroll (30)
include therein the communicating paths (83, 81) which are each
provided with the rod member (89), the narrow channels have a large
length in total although each of the rod members (89) and the
communicating paths (83, 81) is short.
[0031] A seventh aspect of the present disclosure relates to the
scroll compressor of any of the first through the sixth aspects,
further including: a motor (50) configured to drive and rotate the
driving shaft (60); and a connection pipe (84) which is provided
between the casing (15) and the motor (50) and forms part of the
groove communication passage (85), wherein the connection pipe (84)
is a resin pipe made of a resin material or a metal pipe having the
outer circumferential surface coated with a resin material.
[0032] According to the seventh aspect, the connection pipe (84)
which forms part of the groove communication passage (85) is
provided between the casing (15) and the motor (50).
[0033] If a metal pipe was provided on a side of the motor (50), it
would be necessary to space the metal pipe from the motor (50) at a
distance which ensures insulation, and accordingly, the diameter of
the casing (15) would need to be increased in accordance with the
distance between the metal pipe and the motor (50).
[0034] In contrast, according to the seventh aspect, the connection
pipe (84) is a resin pipe made of a resin material or a metal pipe
having the outer circumferential surface coated with a resin
material. Therefore, it is possible to ensure insulation without
distancing the connection pipe (84) from the motor (50).
[0035] An eighth aspect of the present disclosure relates to the
scroll compressor of any of the first through the seventh aspects,
wherein a lubricating oil inlet (88) of the groove communication
passage (85) is located higher than a suction inlet (76) of the
bearing oil supply passage (70).
[0036] Part of the lubricating oil supplied from the oil reservoir
(18) in the casing (15) to the thrust sliding surface (45) and the
thrust sliding surface (35) through the oil groove (80) flows into
compression chambers, and then, is discharged together with
compressed refrigerant to the outside of the casing (15).
Accordingly, the amount of the lubricating oil in the oil reservoir
(18) in the casing (15) decreases and the oil level is becoming
low. When the oil level of the oil reservoir (18) in the casing
(15) has become lower than the lubricating oil inlet (76) of the
bearing oil supply passage (70) and the lubricating oil inlet (88)
of the groove communication passage (85), it is no longer possible
to supply the lubricating oil from the oil reservoir (18) to the
bearing of the driving shaft (60) and the oil groove (80).
[0037] An insufficient amount of lubricating oil supplied to the
bearing of the driving shaft (60) may cause seizure and failure of
the bearing. On the other hand, an insufficient amount of
lubricating oil supplied to the oil groove (80) may cause an
increase in friction force generated between the thrust sliding
surface (45) of the orbiting scroll (40) and the thrust sliding
surface (35) of the fixed scroll (30), and accordingly, an increase
in power consumption of the motor.
[0038] When an insufficient amount of the refrigeration oil is
supplied to the bearing of the driving shaft (60), even for a short
time, the bearing may be fatally damaged and the compressor may
become unable to operate properly. On the other hand, when an
insufficient amount of the refrigeration oil is supplied to the oil
groove (80) only for a short time, the compressor does not suffer
fatal damage although the performance is temporary reduced by
insufficient sealing of the thrust sliding surfaces (35, 45). That
is, an oil shortage of the bearing of the driving shaft (60) must
be dealt with more quickly than an oil shortage of the oil groove
(80).
[0039] To address this problem, the eighth aspect has the
configuration in which the lubricating oil inlet (88) of the groove
communication passage (85) is located higher than the lubricating
oil inlet (76) of the bearing oil supply passage (70). With this
configuration, when the lubricating oil in the oil reservoir (18)
in the casing (15) decreases, the oil level of the oil reservoir
(18) first becomes lower than the inlet (88) of the groove
communication passage (85), and supply of the lubricating oil to
the oil groove (80) is stopped. Consequently, he amount of the
lubricating oil discharged together with the refrigerant to the
outside of the casing (15) decreases, and lowering of the oil level
of the oil reservoir (18) in the casing (15) is alleviated.
Advantages of the Invention
[0040] According to the first aspect of the present disclosure, any
one of the thrust sliding surface (45) of the orbiting scroll (40)
or the thrust sliding surface (35) of the fixed scroll (30)
includes the oil groove (80) formed thereon. The bearing oil supply
passage (70) which supplies the lubricating oil to the bearing in
the compression mechanism (20) is not in communication with the oil
groove (80). Accordingly, even when the orbiting scroll (40) is
tilted and the pressure of the oil groove (80) abruptly drops
during operation of the compression mechanism (20), the pressure of
the bearing oil supply passage (70) remains unchanged.
[0041] If the oil groove (80) and the bearing oil supply passage
(70) communicated with each other, an abrupt pressure drop of the
oil groove (80) would cause a decrease in the pressure of the
bearing oil supply passage (70). The pressure decrease of the
bearing oil supply passage (70) would cause the lubricating oil to
flow backward from the bearing in the compression mechanism (20) to
the bearing oil supply passage (70), and would lead to a shortage
of the lubricating oil for the bearing.
[0042] In contrast, the bearing oil supply passage (70) of the
first aspect is not in communication with the oil groove (80). An
abrupt pressure drop of the oil groove (80) does not cause the
pressure of the bearing oil supply passage (70) to change.
Therefore, according to the first aspect, even when the orbiting
scroll (40) has been tilted and the pressure of the oil groove (80)
has abruptly dropped, the lubricating oil is not allowed to flow
backward from the bearing in the compression mechanism (20) to the
bearing oil supply passage (70), and it is accordingly ensured that
the lubricating oil continues to be supplied to the bearing in the
compression mechanism (20) through the bearing oil supply passage
(70). Consequently, lubrication of the bearing in the compression
mechanism (20) is ensured, and troubles such as seizure are
prevented, thereby enabling improvement of the reliability of the
scroll compressor (10).
[0043] According to the second aspect of the present disclosure,
the lubricating oil discharged from the oil supply pump (75) driven
by the driving shaft (60) passes through the bearing oil supply
passage (70), which is not in communication with the oil groove
(80), to be supplied to the bearing in the compression mechanism
(20). Accordingly, even in a state where the orbiting scroll (40)
has been tilted and the pressure of the oil groove (80) has
abruptly dropped during operation of the compression mechanism
(20), the lubricating oil can be supplied to the bearing in the
compression mechanism (20) in a stable manner. Therefore, according
to the second aspect, it can be ensured that the lubricating oil is
supplied to the bearing in the compression mechanism (20)
regardless of the pressure of the oil groove (80), thereby enabling
improvement of the reliability of the scroll compressor (10).
[0044] According to the third aspect of the present disclosure, the
groove communication passage (85) is provided with the at least one
throttle. Accordingly, even in a state where the orbiting scroll
(40) has been tilted and the clearance between the thrust sliding
surface (45) and the thrust sliding surface (35) has increased, the
throttle controls the flow rate of the lubricating oil in the
groove communication passage (85).
[0045] Here, tilting of the orbiting scroll (40) during operation
of the compression mechanism (20) may reduce a pressure loss caused
when the lubricating oil passes through the clearance between the
thrust sliding surface (45) and the thrust sliding surface (35),
and accordingly, the pressure acting on the thrust sliding surfaces
(35, 45) increases to become approximate to the pressure of the
lubricating oil in the oil groove (80). In such a case, a force
separating the orbiting scroll (40) from the fixed scroll (30)
becomes strong, and the air tightness of the compression chambers
(21) may be reduced.
[0046] To address this problem, the groove communication passage
(85) of the third aspect is provided with the throttle.
Accordingly, even in a state where the orbiting scroll (40) has
been tilted, the flow rate of the lubricating oil flowing from the
groove communication passage (85) into the oil groove (80) and the
pressure of the oil groove (80) are kept low. Consequently, even
when the orbiting scroll (40) has been tilted during operation of
the compression mechanism (20), the pressure acting on the thrust
sliding surfaces (35, 45) is kept low, and the force separating the
orbiting scroll (40) from the fixed scroll (30) is not allowed to
become excessively strong. On the other hand, the pressing force
acts on the orbiting scroll (40) to press the orbiting scroll (40)
against the fixed scroll (30). Therefore, the orbiting scroll (40)
which has been tilted during operation of the compression mechanism
(20) quickly restores the original position by receiving the
pressing force. According to the third aspect, it is possible to
cause the orbiting scroll (40) which has been tilted during
operation of the compression mechanism (20) to quickly restore the
original position, and accordingly, decrease in performance of the
scroll compressor (10) can be alleviated by ensuring air tightness
of the compression chambers (21).
[0047] According to the fourth aspect of the present disclosure,
the throttle which controls the flow rate of the lubricating oil in
the groove communication passage (85) can be easily provided simply
by inserting into the groove communication passage (85) the rod
member (89) having the spiral groove (89e) formed on the outer
circumference. Furthermore, the cross-sectional area of the groove
communication passage (85) can be easily varied simply by changing
the cross-sectional shape of the spiral groove (89e) formed on the
outer circumference of the rod member (89). That is, use of the rod
member (89) as the throttle increases the degree of freedom of
design and makes it easy to change the design.
[0048] When using the rod member (89) having the spiral groove
(89e) on the outer circumference as the throttle for controlling
the flow rate of the lubricating oil in the groove communication
passage (85), the narrow channel formed with the spiral groove
(89e) needs to be long to some extent in order to obtain a
sufficient throttle effect. Increasing the length of the narrow
channel by using a longer rod member (89), however, requires a
longer space in which the longer rod member (89) is placed. In
addition, installation of the longer rod member (89) may require
much time and effort.
[0049] To address this problem, the fifth embodiment of the present
disclosure is configured such that, a plurality of rod members (89)
serving as the throttles are provided in a plurality of locations
of the groove communication passage (85). Accordingly, it is
possible to increase the total length of the narrow channels by
using the rod members (89) each of which is short, and the flow
rate of the lubricating oil in the groove communication passage
(85) can be sufficiently controlled. In other words, providing the
plurality of rod members (89) in the plurality of locations of the
groove communication passage (85) makes it possible to reduce the
length of each of the rod members (89). Consequently, it is
unnecessary to ensure long spaces for installation of the rod
members (89), and the rod members (89) can be easily installed.
[0050] According to the sixth aspect of the present disclosure,
both of the bearing (55) and the fixed scroll (30) include the
communicating paths (83, 81) which form part of the groove
communication passage (85) and are provided with the rod members
(89) serving as the throttles. Accordingly, even if each of rod
members (89) and each of the communicating paths (81, 83) is short,
the narrow channels can have a large length in total. Consequently,
the flow rate of the refrigeration oil in the groove communication
passage (85) can be sufficiently controlled. In other words,
designing each of the bearing member (55) and the fixed scroll (30)
to include the associated communicating path (83, 81) and the
associated rod member (89) provided in the associated communicating
path enables reduction of the length of each of the rod members
(89). Consequently, it is unnecessary to ensure long spaces for
installation of the rod members (89), and the rod members (89) can
be easily installed.
[0051] According to the seventh aspect of the present disclosure, a
resin pipe made of a resin material or a metal pipe having the
outer circumferential surface coated with a resin material is used
as the connection pipe (84) which is provided between the casing
(15) and the motor (50) and forms part of the groove communication
passage (85). Accordingly, it is possible to ensure insulation
without distancing the connection pipe (84) from the motor (50). It
is consequently possible to design the casing (15) to have a
smaller diameter, and to downsize the scroll compressor.
[0052] The eighth aspect of the present disclosure has the
configuration in which the lubricating oil inlet (88) of the groove
communication passage (85) is located higher than the lubricating
oil inlet (76) of the bearing oil supply passage (70). With this
configuration, when the lubricating oil in the oil reservoir (18)
in the casing (15) decreases, supply of the lubricating oil to the
oil groove (80) is first stopped, and accordingly, the amount of
the lubricating oil discharged together with the refrigerant to the
outside of the casing (15) is reduced. Consequently, lowering of
the oil level of the oil reservoir (18) in the casing (15) is
alleviated. Therefore, according to the eighth aspect, even if the
oil level of the oil reservoir (18) in the casing (15) begins to
lower, lowering of the oil level of the oil reservoir (18) in the
casing (15) is alleviated by stopping oil supply to the oil groove
(80). As a result, the oil level of the oil reservoir (18) does not
become lower than the lubricating oil inlet (76) of the bearing oil
supply passage (70), and oil supply to the bearing of the driving
shaft (60) can be ensured. That is, the oil supply to the bearing
of the driving shaft (60) is given a higher priority than the oil
supply to the oil groove (80), and accordingly, fatal failures of
the bearing of the driving shaft (60) caused by seizure can be
prevented.
BRIEF DESCRIPTION OF THE DRAWINGS
[0053] FIG. 1 is a longitudinal cross-sectional view illustrating
an overall configuration of a scroll compressor according to
Embodiment 1.
[0054] FIG. 2 is a longitudinal cross-sectional view illustrating a
configuration of a main portion of the scroll compressor of
Embodiment 1.
[0055] FIG. 3 is a transverse cross-sectional view illustrating a
configuration of a compression mechanism of the scroll compressor
of Embodiment 1.
[0056] FIG. 4 is s longitudinal cross-sectional view illustrating a
configuration of a main portion of a scroll compressor of
Embodiment 2.
[0057] FIG. 5 is a longitudinal cross-sectional view illustrating
an overall configuration of a scroll compressor according to
Embodiment 3.
[0058] FIG. 6 is a longitudinal cross-sectional view illustrating
configurations of first and second connection passages of the
scroll compressor of Embodiment 3.
[0059] FIG. 7 is a longitudinal cross-sectional view illustrating a
configuration of a third connection passage of the scroll
compressor of Embodiment 3.
[0060] FIG. 8 is a longitudinal cross-sectional view illustrating a
configuration of a connection pipe of the scroll compressor of
Embodiment 3.
[0061] FIG. 9 is a longitudinal cross-sectional view illustrating a
main portion of a conventional scroll compressor.
DESCRIPTION OF EMBODIMENTS
[0062] Embodiments of the present disclosure will be described in
detail with reference to the drawings.
Embodiment
[0063] Embodiment 1 of the present disclosure is now described. A
scroll compressor (10) of this embodiment is a hermetic compressor.
The scroll compressor (10) is connected to a refrigerant circuit
which performs a refrigerating cycle, and configured to suck and
compress the refrigerant of the refrigerant circuit.
[0064] <Overall Configuration of Scroll Compressor>
[0065] As illustrated in FIG. 1, the scroll compressor (10)
includes a casing (15), and a compression mechanism (20), a motor
(50), a lower bearing member (55), and a driving shaft (60) are
housed in the inner space of the casing (15). The casing (15) is a
hermetic container having a vertically oriented cylindrical shape.
In the inner space of the casing (15), the compression mechanism
(20), the motor (50), and the lower bearing member (55) are
arranged in this order from top to bottom. The driving shaft (60)
is disposed such that the axial direction of the driving shaft (60)
is along the vertical direction of the casing (15). The structure
of the compression mechanism (20) will be detailed later.
[0066] The casing (15) is provided with a suction pipe (16) and a
discharge pipe (17). Both of the suction pipe (16) and the
discharge pipe (17) penetrate the wall of the casing (15). The
suction pipe (16) is connected to the compression mechanism (20).
The discharge pipe (17) opens in room between the motor (50) and
the compression mechanism (20) in the inner space of the casing
(15).
[0067] The lower bearing member (55) includes a central cylindrical
portion (56), and is provided with three arms (57), only one of
which is illustrated in FIG. 1. The central cylindrical portion
(56) has a nearly cylindrical shape. Each of the arms (57) extends
outwardly from the outer circumferential surface of the central
cylindrical portion (56). The angles formed between adjacent ones
of the three arms (57) provided on the lower bearing member (55)
are substantially equal to one another. The end of each of the arms
(57) is secured to the casing (15). A bearing metal (58) penetrates
a part of the central cylindrical portion (56) near its upper end.
The bearing metal (58) is penetrated by an auxiliary journal
portion (67) of the driving shaft (60) which will be described
later. The central cylindrical portion (56) forms a journal bearing
which supports the auxiliary journal portion (67).
[0068] The motor (50) includes a stator (51) and a rotor (52). The
stator (51) is secured to the casing (15). The rotor (52) is
disposed coaxially with the stator (51). The rotor (52) is
penetrated by a main shaft portion (61) of the driving shaft (60)
which will be described later.
[0069] The driving shaft (60) includes the main shaft portion (61),
a balance weight (62), and an eccentric portion (63). The balance
weight (62) is located in an intermediate part in the axial
direction of the main shaft portion (61). Part of the main shaft
portion (61) located below the balance weight (62) penetrates the
rotor (52) of the motor (50). Part of the main shaft portion (61)
located above the balance weight (62) forms a main journal portion
(64). The auxiliary journal portion (67) is located below the part
of the in shaft portion (61) penetrating the rotor (52). The main
journal portion (64) penetrates a bearing metal (28) provided in a
central bulge portion (27) of a housing (25). The auxiliary journal
portion (67) penetrates the bearing metal (58) provided in the
central cylindrical portion (56) of the lower bearing member
(55).
[0070] The eccentric portion (63) has a circular column shape
having a diameter smaller than the diameter of the main journal
portion (64), and projects from the upper end surface of the main
journal portion (64). The shaft center of the eccentric portion
(63) is parallel with and eccentric relative to the shaft center of
the main journal portion (64) (i.e., the shaft center of the main
shaft portion (61)). The eccentric portion (63) penetrates a
bearing metal (44) provided in a cylindrical portion (43) of an
orbiting scroll (40).
[0071] The driving shaft (60) has an oil supply passage (77) formed
therein. The oil supply passage (77) includes a main passage (74)
and three branch passages (71-73). The main passage (74) extends
along the shaft center of the driving shaft (60), and has an end
which opens at the lower end of the main shaft portion (61) and the
other end which opens on the upper end surface of the eccentric
portion (63). The first branch passage (71) is located in the
eccentric portion (63). The first branch passage (71) outwardly
extends from the main passage (74) in a radial direction of the
eccentric portion (63) and opens on the outer circumferential
surface of the eccentric portion (63). The second branch passage
(72) is located in the main journal portion (64). The second branch
passage (72) outwardly extends from the main passage (74) in a
radial direction of the main journal portion (64) and opens on the
outer circumferential surface of the main journal portion (64). The
third branch passage (73) is located in the auxiliary journal
portion (67). The third branch passage (73) outwardly extends from
the main passage (74) in a radial direction of the auxiliary
journal portion (67) and opens on the outer circumferential surface
of the auxiliary journal portion (67).
[0072] An oil supply pump (75) is mounted at the lower end of the
driving shaft (60). The oils supply pump (75) is a trochoid pump
which is driven by the driving shaft (60). The oil supply pump (75)
is disposed near the starting end of the main passage (74) of the
oil supply passage (77). The oil supply pump (75) has, at the lower
end, a suction inlet (76) which opens downwardly and through which
a refrigeration oil serving as lubricating oil is sucked. Note that
the oil supply pump (75) is not limited to the trochoid pump and
may be any displacement e pump driven by the driving shaft (60).
Accordingly, the oil supply pump (75) may be a gear pump, for
example. The oil supply pump (75) and the oil supply passage (77)
together form a bearing oil supply passage (70) which supplies the
refrigeration oil to journal bearings of the compression mechanism
(20) which will be described later. The suction inlet (76) of the
oil supply pump (75) serves as a refrigeration oil inlet for the
bearing oil supply passage (70).
[0073] The refrigeration oil serving as lubricating oil is stored
in a bottom portion of the casing (15). That is, the casing (15)
has an oil reservoir (18) in its bottom portion. When the driving
shaft (60) rotates, the oil supply pump (75) sucks the
refrigeration oil from the oil reservoir (18) and discharges the
same. The refrigeration oil discharged from the oil supply pump
(75) flows through the main passage (74). The refrigeration oil
flowing through the main passage (74) is supplied to the lower
bearing member (55) and sliding parts of the compression mechanism
(20) and the driving shaft (60). Since the oil supply pump (75) is
a displacement pump, the rate of the refrigeration oil in the main
passage (74) is proportional to the rotation speed of the driving
shaft (60).
[0074] <Configuration of Compression Mechanism>
[0075] As illustrated in FIG. 2, the compression mechanism (20)
includes the housing (25), a fixed scroll (30), and the orbiting
scroll (40). The compression mechanism (20) is provided with an
Oldham's coupling (24) for controlling rotation of the orbiting
scroll (40).
[0076] The housing (25) has a disk shape with a large wall
thickness, and the outer circumferential edge of the housing (25)
is secured to the casing (15). The housing (25) has a central
recess (26) and an annular projection (29) formed in its central
part. The central recess (26) is a recess which has a circular
column shape and opens on the upper surface of the housing (25).
The annular projection (29) surrounds the central recess (26) and
projects from the upper surface of the housing (25). The annular
projection (29) has a flat top surface on which a ring-shaped
groove is formed along the circumference of the annular projection
(29). A seal ring (29a) is fitted in this groove.
[0077] The housing (25) has the central bulge portion (27) formed
thereon. The central bulge portion (27) is located below the
central recess (26) and bulges downward. The central bulge portion
(27) has a through hole which vertically penetrates the central
bulge portion (27). The bearing metal (28) penetrates through this
through hole. The main journal portion (64) of the driving shaft
(60) penetrates the bearing metal (28) of the central bulge portion
(27). The central bulge portion (27) forms the journal bearing
which supports the main journal portion (64).
[0078] The fixed scroll (30) and the orbiting scroll (40) are
disposed on the housing (25). The fixed scroll (30) is secured to
the housing (25) with, e.g. bolts. On the other hand, the orbiting
scroll (40) is engaged with the housing (25) via the Oldham's
coupling (24), and is provided movably relative to the housing
(25). The orbiting scroll (40), which is engaged with driving shaft
(60), performs orbital motion,
[0079] The orbiting scroll (40) is a component into which an end
plate (41), a lap (42), and the cylindrical portion (43) are
integrated. The end plate (41) of the orbiting scroll (40) has a
disk-like shape. The lap (42) of the orbiting scroll (40) is formed
in a spiral-shaped wall, and projects from the front side of the
end plate (41) (i.e. from the upper surface of the end plate (41)
in FIGS. 1 and 2). The cylindrical portion (43) has a cylindrical
shape and projects from the backside of the end plate (41) (i.e.
from the lower surface of the end plate (41) in FIGS. 1 and 2).
[0080] The backside of the end plate (41) of the orbiting scroll
(40) is in sliding contact with the seal ring (29a) disposed on the
annular projection (29) of the housing (25). On the other hand, the
cylindrical portion (43) of the orbiting scroll (40) downwardly
penetrates the central recess (26) of the housing (25). The bearing
metal (44) penetrates the cylindrical portion (43). The eccentric
portion (63) of the driving shaft (60) which will be detailed later
upwardly penetrates the bearing metal (44) of the cylindrical
portion (43). The cylindrical portion (43) forms the journal
bearing which slides on the eccentric portion (63).
[0081] The fixed scroll (30) is a component into which an end plate
(31), a lap (32), and an outer circumferential portion (33) are
integrated. The end plate (31) of the fixed scroll (30) has a
disk-like shape. The lap (32) of the fixed scroll (30) is formed in
a spiral-shaped wall, and projects from the front side of the end
plate (31) (i.e. from the lower surface of the end plate (31) in
FIGS. 1 and 2). The outer circumferential portion (33) has a ring
shape with a large wall thickness, and downwardly extends from the
outer circumference of the end plate (31) to surround the lap
(32).
[0082] The end plate (31) has a discharge port (22) formed therein.
The discharge port (22) is a through hole formed near the center of
the end plate (31), and penetrates the end plate (31) in the
thickness direction. The suction pipe (16) penetrates a part of the
end plate (31) near the outer circumference.
[0083] The compression mechanism (20) has a discharged gas passage
(23) formed therein. The discharged gas passage (23) has the
starting end which communicates with the discharge port (22).
Although not shown, the discharged gas passage (23) extends from
the fixed scroll (30) to the housing (25), and has the other end
which opens on the lower surface of the housing (25).
[0084] In the compression mechanism (20), the fixed scroll (30) and
the orbiting scroll (40) are disposed such that the front side of
the end plate (31) faces the front side of the end plate (41), and
the lap (32) and the lap (42) are engaged with each other.
Accordingly, in the compression mechanism (20), a plurality of
compression chambers (21) are formed by engagement of the laps (32,
42).
[0085] In the compression mechanism (20), the end plate (41) of the
orbiting scroll (40) is in sliding contact with the outer
circumferential portion (33) of the fixed scroll (30).
Specifically, on the front side of the end plate (41) (i.e. on the
upper surface of the end plate (41) in FIGS. 1 and 2), a part
located outward relative to the lap (42) serves as a thrust sliding
surface (45) which is in sliding contact with the fixed scroll
(30). On the other hand, on the outer circumferential portion (33)
of the fixed scroll (30), the top surface (i.e., the lower surface
of the outer circumferential portion (33) in FIGS. 1 and 2) is in
sliding contact with the thrust sliding surface (45) of the
orbiting scroll (40). In the outer circumferential portion (33), a
part which is in sliding contact with the thrust sliding surface
(45) serves as a thrust sliding surface (35) of the fixed scroll
(30).
[0086] As illustrated in FIGS. 2 and 3, the outer circumferential
portion (33) of the fixed scroll (30) has an oil groove (80) and a
connection passage (86) formed therein. The oil groove (80) is a
groove formed by depressing the thrust sliding surface (35) of the
outer circumferential portion (33), and has a ring shape
surrounding the lap (32). The connection passage (86) has an end
which communicates with the oil groove (80). The connection passage
(86) extends from the end toward the outer circumference of the
outer circumferential portion (33). A capillary tube (87) which
will be detailed later is connected to a part near the other end of
the connection passage (86). The connection passage (86) and the
capillary tube (87) together form a groove communication passage
(85).
[0087] The capillary tube (87) is a thin copper tube with an inside
diameter of 0.5-1.0 mm, and serves as a throttle. The capillary
tube (87) extends along the inner surface of the casing (15).
Specifically, the capillary tube (87), which passes through a
through hole formed in the housing (25) and penetrates the outer
circumferential portion (33) of the fixed scroll (30), has the
upper end communicating with the connection passage (86). The
capillary tube (87) also penetrates through a core-cut part formed
in the stator (51) of the motor (50) to reach the oil reservoir
(18). Thus, the capillary tube (87) has the lower end soaked in the
refrigeration oil stored in the bottom portion of the casing
(15).
[0088] The lower end opening (88) of the capillary tube (87) serves
as a refrigeration oil inlet through which the refrigeration oil is
caused to flow into the groove communication passage (85). The
lower end opening (88) of the capillary tube (87) is located higher
than the suction inlet (76) of the oil supply pump (75). In this
embodiment, the lower end opening (88) of the capillary tube (87)
is located about 10 mm above the suction inlet (76) of the oil
supply pump (75). That is, the inlet of the groove communication
passage (85) is located higher than the refrigeration oil inlet of
the bearing oil supply passage (70).
[0089] In this embodiment, the groove communication passage (85)
constituted by the connection passage (86) and the capillary tube
(87) connects the oil groove (80) only to the oil reservoir (18) in
the casing (15). Accordingly, in this embodiment, the oil supply
passage (77) formed in the driving shaft (60) is not in
communication with the oil groove (80) located on the fixed scroll
(30). That is, the bearing oil supply passage (70) is not in
communication with the oil groove (80).
[0090] Operation
[0091] Operation by the scroll compressor (10) is now
described.
[0092] <Operation to Compress Refrigerant>
[0093] In the scroll compressor (10), when the motor (50) is
supplied with electricity, the driving shaft (60) drives the
orbiting scroll (40). Since rotation of the orbiting scroll (40) is
controlled by the Oldham's coupling (24), the orbiting scroll (40)
only performs orbital motion without rotating.
[0094] When the orbiting scroll (40) performs orbital motion, the
gaseous refrigerant with a low pressure having flowed into the
compression mechanism (20) through the suction pipe (16) is sucked
into the compression chamber (21) from the portions near the outer
circumferential ends of the lap (32) and the lap (42). When the
orbiting scroll (40) further moves, the compression chamber (21)
becomes isolated from the suction pipe (16) to enter a completely
closed state. The compression chamber (21) then moves along the lap
(32) and the lap (42) toward the inner circumferential ends of the
laps (32, 42). During this movement, the volume of the compression
chamber (21) gradually decreases, and accordingly, the gaseous
refrigerant in the compression chamber (21) is compressed in a
gradual manner.
[0095] After the gradual decrease in the volume of the compression
chamber (21) caused by the movement of the orbiting scroll (40),
the compression chamber (21) comes into communication with the
discharge port (22). The compressed refrigerant (i.e., the gaseous
refrigerant with a high pressure) in the compression chamber (21)
flows through the discharge port (22) to enter the discharge gas
passage (23), and then is discharged to the inner space of the
casing (15). In the inner space of the casing (15), the
high-pressure gaseous refrigerant having been discharged from the
compression mechanism (20) is initially guided to room below the
stator (51) of the motor (50), and then, allowed to flow upwardly
through, e.g., a gap between the rotor (52) and the stator (51).
Thereafter, the gaseous refrigerant passes through the discharge
pipe (17) to flow out to the outside of the casing (15).
[0096] In room below the housing (25) located in the inner space of
the casing (15), the high-pressure gaseous refrigerant having been
discharged from the compression mechanism (20) is flowing, and the
room below the housing (25) has a pressure substantially equal to
the pressure of the high-pressure gaseous refrigerant. Accordingly,
the refrigeration oil stored in the oil reservoir (18) in the
casing (15) has a pressure substantially equal to the pressure of
the high-pressure gaseous refrigerant.
[0097] On the other hand, room above the housing (25) located in
the inner space of the casing (15), although not shown,
communicates with the suction pipe (16), and has a pressure
approximate to the pressure of the low-pressure gaseous refrigerant
sucked into the compression mechanism (20). Accordingly, in the
compression mechanism (20), room near the outer circumference of
the end plate (41) of the orbiting scroll (40) has a pressure
approximate the pressure of the low-pressure gaseous
refrigerant.
[0098] <Operation to Supply Oil to Compression Mechanism>
[0099] During operation of the scroll compressor (10), the driving
shaft (60) rotates and drives the oil supply pump (75), and the
refrigeration oil stored in the bottom portion of the casing (15)
is sucked and supplied to the main passage (74) of the oil supply
passage (77). Part of the refrigeration oil flowing through the
main passage (74) flows into the branch passages (71-73) and the
remainder of the refrigeration oil flows out from the upper end of
the main passage (74).
[0100] The refrigeration oil having flowed into the first branch
passage (71) is supplied to a gap between the eccentric portion
(63) and the bearing metal (44) to be used to lubricate and cool
the eccentric portion (63) and the bearing metal (44). The
refrigeration oil having flowed into the second branch passage (72)
is supplied to a gap between the main journal portion (64) and the
bearing metal (28) to be used to lubricate and cool the main
journal portion (64) and the bearing metal (28). The refrigeration
oil having flowed into the third branch passage (73) is supplied to
a gap between the auxiliary journal portion (67) and the bearing
metal (58) to be used to lubricate and cool the auxiliary journal
portion (67) and the bearing metal (58). In addition, in the
compression mechanism (20), the sliding parts of the orbiting
scroll (40) and the Oldham's coupling (24) and the sliding parts of
the orbiting scroll (40) and the fixed scroll (30) are supplied
with the refrigeration oil.
[0101] <Operation to Press Orbiting Scroll>
[0102] The compression mechanism (20) of this embodiment is
configured such that the orbiting scroll (40) is pressed against
the fixed scroll (30) by using the refrigeration oil supplied from
the oil reservoir (18) located in the casing (15).
[0103] Specifically, in the compression mechanism (20), the
backside of the end plate (41) of the orbiting scroll (40) is in
sliding contact with the seal ring (29a). The refrigeration oil
having flowed out from the terminal end of the main passage (74) of
the oil supply passage (77) is present in the central recess (26)
located inside that seal ring (29a). This refrigeration oil has a
pressure approximate to the pressure of the refrigeration oil in
the oil reservoir (18).
[0104] In the orbiting scroll (40), the pressure of the
refrigeration oil having flowed out from the main passage (74) acts
on a part of the backside of the end plate (41) located inside the
seal ring (29a), and on the surface of the cylindrical portion
(43). Consequently, a pressing force toward the fixed scroll (30)
(i.e., an upward force in this embodiment) acts on the orbiting
scroll (40). As a result, also during operation of the compression
mechanism (20), the orbiting scroll (40) is kept pressed against
the fixed scroll (30), thereby ensuring air tightness of the
compression chambers (21).
[0105] However, the pressing force acting on the orbiting scroll
(40) sometimes becomes too strong. The excessively strong pressing
force increases the friction force acting between the orbiting
scroll (40) and the fixed scroll (30), and accordingly, causes an
increase in power consumption of the motor (50).
[0106] To address this problem, the scroll compressor (10) of this
embodiment includes the oil groove (80) which communicates with the
oil reservoir (18) in the casing (15) through the groove
communication passage (85) and which is kept filled with the
high-pressure refrigeration oil. On the other hand, the compression
chamber (21) adjacent to the oil groove (80) (i.e., the compression
chamber (21) formed near the outermost parts of the laps (32, 42))
has a pressure approximate to the pressure of the low-pressure
refrigerant sucked into the compression chamber (21) and which is
lower than the pressure of the refrigeration oil in the oil groove
(80). Consequently, the refrigeration oil in the oil groove (80)
gradually flows out to enter a clearance between the thrust sliding
surface (45) and the thrust sliding surface (35) to be used to
lubricate the thrust sliding surfaces (35, 45).
[0107] In this manner, the scroll compressor (10) of this
embodiment ensures that the refrigeration oil is supplied to the
clearance between the thrust sliding surface (45) and the thrust
sliding surface (35). Accordingly, even in a state where the
orbiting scroll (40) is strongly pressed against the fixed scroll
(30), the friction force between the thrust sliding surface (45)
and the thrust sliding surface (35) does not become excessively
strong.
[0108] <Operation Performed When Orbiting Scroll is
Tilted>
[0109] In the orbiting scroll (40) of the scroll compressor (10),
the internal pressure of the compression chambers (21) acts on the
lap (42) projecting from the front side of the end plate (41), and
a load from the eccentric portion (63) acts on the cylindrical
portion (43) projecting from the backside of the end plate (41).
The line of action of the gas pressure acting on the lap (42) and
the line of action of the load acting on the cylindrical portion
(43) intersect the axial direction of the orbiting scroll (40) at
right angles but do not intersect each other. Accordingly, during
operation of the compression mechanism (20), a moment acts on the
orbiting scroll (40) in a direction tilting the orbiting scroll
(40). If the pressing force acting on the orbiting scroll (40) is
sufficiently strong, the orbiting scroll (40) is not tilted even by
the moment acting thereon.
[0110] However, in an operational state where the pressing force is
insufficiently strong, the orbiting scroll (40) is sometimes
tilted, thereby increasing the clearance between the thrust sliding
surface (45) and the thrust sliding surface (35). For example, the
pressing force may become insufficiently strong in an operational
state where the pressure difference between the low-pressure
gaseous refrigerant sucked into the compression mechanism (20) and
the high-pressure gaseous refrigerant discharged from the
compression mechanism (20) is small, or in an operational state
where the rotation speed of the driving shaft (60) is considerably
low (e.g., 10-20 rotations per second).
[0111] As described above, in the compression mechanism (20), the
pressure of the room near the outer circumference of the end plate
(41) is approximate to the pressure of the low-pressure gaseous
refrigerant sucked into the compression mechanism (20). On the
other hand, when the orbiting scroll (40) is tilted and the
clearance between the thrust sliding surface (45) and the thrust
sliding surface (35) increases, a flow resistance in the clearance
between the thrust sliding surfaces (35, 45) decreases.
Accordingly, tilting of the orbiting scroll (40) may cause a large
amount of the refrigeration oil to spout out from the oil groove
(80) to the room near the outer circumference of the end plate
(41).
[0112] In addition, tilting of the orbiting scroll (40) may reduce
a pressure loss caused when the refrigeration oil passes through
the clearance between the thrust sliding surface (45) and the
thrust sliding surface (35), and accordingly, the pressure acting
on the thrust sliding surfaces (35, 45) increases to become
approximate to the pressure of the refrigeration oil in the oil
groove (80). In such a case, a force separating the orbiting scroll
(40) from the fixed scroll (30) becomes strong, and the air
tightness of the compression chambers (21) may be reduced.
[0113] To address this problem, the scroll compressor (10) of this
embodiment includes the capillary tube (87) provided in the groove
communication passage (85). Even in a state where the orbiting
scroll (40) has been tilted and the clearance between the thrust
sliding surface (45) and the thrust sliding surface (35) has
increased, the capillary tube (87) controls the flow rate of the
refrigeration oil in the groove communication passage (85).
[0114] In this manner, in the compression mechanism (20) of this
embodiment, even in a state where the orbiting scroll (40) has been
tilted, the flow rate of the refrigeration oil flowing from the
groove communication passage (85) to the oil groove (80) and the
pressure of the oil groove (80) are kept low. Consequently, even if
the orbiting scroll (40) is tilted during operation of the
compression mechanism (20), the pressure acting on the thrust
sliding surfaces (35, 45) is kept low, and the force separating the
orbiting scroll (40) from the fixed scroll (30) is not allowed to
become excessively strong. On the other hand, the pressing force
acts on the orbiting scroll (40) to press the orbiting scroll (40)
against the fixed scroll (30). Therefore, the orbiting scroll (40)
which has been tilted during operation of the compression mechanism
(20) quickly restores the original position by receiving the
pressing force.
[0115] Here, if the pressure loss caused when the refrigeration oil
moves from one end to the other end of the groove communication
passage (85) is too small and tilting of the orbiting scroll (40)
causes the pressure in the oil groove (80) to decrease, the flow
rate of the refrigeration oil in the groove communication passage
(85) abruptly increases and a large amount of the refrigeration oil
spouts from the terminal end of the groove communication passage
(85). On the other hand, if the pressure loss caused when the
refrigeration oil moves from an end to the other end of the groove
communication passage (85) is too large, it may take a longer time
for the pressure of the oil groove (80) to become sufficiently high
after tilting of the orbiting scroll (40) has been eliminated, and
an insufficient amount of the refrigeration oil may be supplied to
the clearance between the thrust sliding surface (45) and the
thrust sliding surface (35).
[0116] To address this problem, in this embodiment, the connection
passage (86) and the capillary tube (87) together form the groove
communication passage (85). According to this embodiment, the
inside diameter and the length of the capillary tube (87) are
adjusted such that the pressure loss caused when the refrigeration
oil moves from one end to the other of the groove communication
passage (85) becomes an appropriate value.
[0117] <Operation to Control Lowering of Oil Level of Oil
Reservoir>
[0118] As described above, in the scroll compressor (10) of this
embodiment, the refrigeration oil in the oil groove (80) gradually
flows out to enter the clearance between the thrust sliding surface
(45) of the orbiting scroll (40) and the thrust sliding surface
(35) of the fixed scroll (30) to be used to lubricate the thrust
sliding surfaces (35, 45). Part of the refrigeration oil having
been used to lubricate the thrust sliding surfaces flows into the
compression chamber (21) adjacent to the oil groove (80), and is
then discharged together with the gaseous refrigerant to the inner
spacer of the casing (15). The discharged refrigeration oil and the
gaseous refrigerant are dispersed within the inner space of the
casing (15), and then, are initially guided to room below the
stator (51) of the motor (50). Part of the refrigeration oil drops
to be stored in the oil reservoir (18) whereas the remainder of the
refrigeration oil and the gaseous refrigerant flow upwardly
through, e.g., a gap between the rotor (52) and the stator (51) to
be discharged to the outside of the casing (15) through the
discharge pipe (17).
[0119] The refrigeration oil which has been discharged together
with the gaseous refrigerant to the outside of the casing (15) in
the above described manner circulates, together with the
refrigerant, through the refrigerant circuit to which the scroll
compressor (10) is connected, and then, is sucked again into the
scroll compressor (10). The refrigeration oil having been sucked
into the scroll compressor (10) is discharged together with the
compressed gaseous refrigerant to the inner space of the casing
(15). Part of the refrigeration oil is returned to the oil
reservoir (18) in the casing (15).
[0120] Meanwhile, depending on operational states, return of the
refrigeration oil to casing (15) of the scroll compressor (10) is
sometimes impeded. For example, a low temperature of an evaporator
causes an increase in the viscosity of the refrigeration oil. This
increase in the viscosity causes the refrigeration oil to easily
accumulate in the evaporator, and results in an impediment to
return of the refrigeration oil to the scroll compressor (10). When
this operation state continues, the amount of the refrigeration oil
discharged together with gaseous refrigerant from the casing (15)
becomes larger than the amount of refrigeration oil returned to the
casing (15). Accordingly, the amount of the refrigeration oil in
the oil reservoir (18) decreases, resulting in that the oil level
is lowered. When the oil level of the oil reservoir (18) in the
casing (15) becomes lower than the suction inlet (76) of the oil
supply pump (75) (i.e., the refrigeration oil inlet of the bearing
oil supply passage (70)) and the lower end opening (88) of the
capillary tube (87) (i.e., the refrigeration oil inlet of the
groove communication passage (85)), it becomes impossible to supply
the refrigeration oil from the oil reservoir (18) to the journal
bearings and the oil groove (80) of the compression mechanism
(20).
[0121] An insufficient amount of the refrigeration oil supplied to
the journal bearings of the compression mechanism (20) may cause
seizure and failure of the journal bearings. On the other hand, an
insufficient amount of the refrigeration oil supplied to the oil
groove (80) may cause an increase in the friction force between the
thrust sliding surface (45) of the orbiting scroll (40) and the
thrust sliding surface (35) of the fixed scroll (30), and an
increase in the power consumption of the motor.
[0122] When an insufficient amount of the refrigeration oil is
supplied to the bearing of the driving shaft (60), even for a short
time, the journal bearings may be fatally damaged and the
compressor may become unable to operate properly. On the other
hand, when an insufficient amount of the refrigeration oil is
supplied to the oil groove (80) only for a short time, the
compressor does not suffer fatal damage although the performance is
temporary reduced by insufficient sealing of the thrust sliding
surfaces (35, 45). That is, an oil shortage of the journal bearings
of the compression mechanism (20) must be dealt with more quickly
than an oil shortage of the oil groove (80).
[0123] To address this problem, the scroll compressor (10) of this
embodiment has the configuration in which the lower end opening
(88) of the capillary tube (87) serving as the refrigeration oil
inlet of the groove communication passage (85) is located higher
than the suction inlet (76) of the oil supply pump (75) serving as
the refrigeration oil inlet of the bearing oil supply passage (70).
With this configuration, when the refrigeration oil in the oil
reservoir (18) in the casing (15) decreases, the oil level of the
oil reservoir (18) first becomes lower than the lower end opening
(88) of the capillary tube (87), and supply of the refrigeration
oil to the oil groove (80) is stopped. Thus, even when the oil
level of the oil reservoir (18) in the casing (15) is lowered, the
stop of supply of the refrigeration oil to the oil groove (80)
causes a decrease in the amount of the refrigeration oil discharged
together with the refrigerant to the outside of the casing (15).
Consequently, the amount of the refrigeration oil discharged to the
outside of the casing (15) falls short of the amount of the
refrigeration oil returned to the inside of the casing (15), and
lowering of the oil level of the oil reservoir (18) in the casing
(15) is alleviated. In this manner, lowering of the oil level of
the oil reservoir (18) in the casing (15) is alleviated such that
the oil level of the oil reservoir (18) will not become lower than
the suction inlet (76) of the bearing oil supply passage (70) and
oil supply to the journal bearings of the compression mechanism
(20) is ensured.
[0124] Advantages of Embodiment 1
[0125] According to this embodiment, the fixed scroll (30) has the
oil groove (80) formed on the thrust sliding surface (35). The
bearing oil supply passage (70) supplying the refrigeration oil to
the journal bearings of the compression mechanism (20) is not in
communication with the oil groove (80). Therefore, even when the
orbiting scroll (40) is tilted and the pressure of the oil groove
(80) abruptly drops during operation of the compression mechanism
(20), the pressure of the bearing oil supply passage (70) remains
unchanged.
[0126] If the oil groove (80) and the bearing oil supply passage
(70) communicated with each other, an abrupt pressure drop of the
oil groove (80) would cause a decrease in the pressure of the
bearing oil supply passage (70). The pressure decrease of the
bearing oil supply passage (70) would cause the refrigeration oil
to flow backward from the journal bearings of the compression
mechanism (20) to the bearing oil supply passage (70), and would
lead to a shortage of the lubricating oil for the journal
bearings.
[0127] In contrast, the bearing oil supply passage (70) of this
embodiment is not in communication with the oil groove (80). An
abrupt pressure drop of the oil groove (80) does not cause the
pressure of the bearing oil supply passage (70) to change.
Therefore, according to this embodiment, even if the orbiting
scroll (40) is tilted and the pressure of the oil groove (80)
abruptly drops, the refrigeration oil is not allowed to flow
backward from the journal bearings of the compression mechanism
(20) to the bearing oil supply passage (70), and it is accordingly
ensured that the refrigeration oil continues to be supplied to the
journal bearings of the compression mechanism (20) through the
bearing oil supply passage (70). Consequently, lubrication of the
journal bearings of the compression mechanism (20) is ensured, and
troubles such as seizure are prevented, thereby enabling
improvement of the reliability of the scroll compressor (10).
[0128] In this embodiment, the refrigeration oil discharged from
the oil supply pump (75) driven by the driving shaft (60) passes
through the bearing oil supply passage (70), which is not in
communication with the oil groove (80), to be supplied to the
journal bearings of the compression mechanism (20). Accordingly,
even in a state where the orbiting scroll (40) has been tilted and
the pressure of the oil groove (80) has abruptly dropped during
operation of the compression mechanism (20), the refrigeration oil
can be supplied to the journal bearings of the compression
mechanism (20) in a stable manner. Therefore, according to this
embodiment, supply of the refrigeration oil to the journal bearings
of the compression mechanism (20) is endured regardless of the
pressure of the oil groove (80), and accordingly, it can be ensured
that troubles such as seizure of the journal bearings are
avoided.
[0129] When the orbiting scroll (40) is tilted under conditions in
which the pressure loss caused when the refrigeration oil moves
from one end to the other of the groove communication passage (85)
is too small, the clearance between the thrust sliding surface (45)
and the thrust sliding surface (35) is increased by the tilting of
the orbiting scroll (40), and consequently, a large amount of the
refrigeration oil spouts from the terminal end of the groove
communication passage (85). Under conditions in which the pressure
loss caused when the refrigeration oil moves from one end to the
other of the groove communication passage (85) is too large, it may
take a longer time for the pressure of the oil groove (80) to
become sufficiently high after tilting of the orbiting scroll (40)
has been eliminated, and an insufficient amount of the
refrigeration oil may be supplied to the clearance between the
thrust sliding surface (45) and the thrust sliding surface
(35).
[0130] To address this problem, in this embodiment, the capillary
tube (87) forms part of the groove communication passage (85) such
that the pressure loss caused when the refrigeration oil moves from
one end to the other of the groove communication passage (85) is
adjusted to an appropriate value. Accordingly, even in a state
where the orbiting scroll (40) has been tilted, it is possible to
prevent the flow rate of the refrigeration oil in the groove
communication passage (85) from increasing excessively.
Consequently, even when the orbiting scroll (40) is tilted, the
pressure of the oil groove (80) can be kept low by controlling the
flow rate of the refrigeration oil flowing from the groove
communication passage (85) into the oil groove (80), and
accordingly, it is possible to cause the tilted orbiting scroll
(40) to restore the original position quickly. In addition, once
the orbiting scroll (40) has restored the original position, the
pressure of the oil groove (80) can be quickly increased to ensure
that a sufficient amount of the refrigeration oil is supplied to
the clearance between the thrust sliding surface (45) and the
thrust sliding surface (35).
[0131] In the scroll compressor (10) of this embodiment, the lower
end opening (88) of the capillary tube (87) serving as the
refrigeration oil inlet of the groove communication passage (85) is
located higher than the suction inlet (76) of the oil supply pump
(75) serving as the refrigeration oil inlet of the bearing oil
supply passage (70). Accordingly, lowering of the oil level of the
oil reservoir (18) in the casing (15) first stops supply of the
refrigeration oil to the oil groove (80), and the amount of the
refrigeration oil discharged together with the refrigerant to the
outside of the casing (15) is reduced. Consequently, the amount of
the refrigeration oil discharged to the outside of the casing (15)
falls short of the amount of the refrigeration oil returned to the
inside of the casing (15), and lowering of the oil level of the oil
reservoir (18) in the casing (15) is alleviated. Therefore,
according to the scroll compressor (10) of this embodiment, even if
the oil level of the oil reservoir (18) in the casing (15) begins
to lower, lowering of the oil level of the oil reservoir (18) in
the casing (15) is alleviated by stopping supply of the
refrigeration oil to the oil groove (80) such that the oil level of
the oil reservoir (18) will not become lower than the inlet (76) of
the oil supply pump (75), and the oil supply to the journal
bearings of the compression mechanism (20) can be ensured. That is,
the oil supply to the journal bearings of the compression mechanism
(20) is given a higher priority than the oil supply to the oil
groove (80), and fatal failures of the journal bearings can be
prevented.
Embodiment 2
[0132] Embodiment 2 of the present disclosure will be described
below, focusing on differences between a scroll compressor (10) of
Embodiment 2 and that of Embodiment 1.
[0133] As illustrated in FIG. 4, in a compression mechanism (20) of
this embodiment, an oil groove (80) is formed not on a fixed scroll
(30) but on an orbiting scroll (40). Specifically, the oil groove
(80) of this embodiment is located on an end plate (41) of the
orbiting scroll (40). The oil groove (80) is a groove formed by
depressing a thrust sliding surface (45) of the end plate (41), and
has a ring shape surrounding a lap (42) of the orbiting scroll
(40). In this embodiment, a terminal end of a connection passage
(86) opens on a thrust sliding surface (35) of the fixed scroll
(30). The terminal end of the connection passage (86) has a large
width such that the connection passage (86) can continue to
communicate with the oil groove (80) even when the orbiting scroll
(40) moves,
[0134] According to this embodiment, in a manner similar to
Embodiment 1, a bearing oil supply passage (70) is not in
communication with the oil groove (80), a refrigeration oil is
caused to flow through the groove communication passage (85) only
by a pressure difference between an oil reservoir (18) in a casing
(15) and the oil groove (80), and a capillary tube (87) forms part
of the groove communication passage (85). Accordingly, this
embodiment provides advantages similar to those of Embodiment
1.
Embodiment 3
[0135] Embodiment 3 of the present disclosure will be described
below, focusing on differences between a scroll compressor (10) of
Embodiment 3 and that of Embodiment 1.
[0136] As illustrated in FIG. 5, in this embodiment, a central
cylindrical portion (56) of a lower bearing member (55) is
different from that of Embodiment 1. Specifically, the central
cylindrical portion (56) extends along an auxiliary shaft portion
(67) which forms a lower end part of a driving shaft (60), from the
upper end to the lower end of auxiliary shaft portion (67). The
central cylindrical portion (56) has a recess formed in an upper
end part thereof, and a rolling bearing (54) is provided in the
recess. The rolling bearing (54) is penetrated by the auxiliary
shaft portion (67) of the driving shaft (60). With this
configuration, the central cylindrical portion (56) serves as an
auxiliary bearing which supports the auxiliary shaft portion
(67).
[0137] Further, in this embodiment, a first connection passage (81)
formed in a fixed scroll (30), a second connection passage (82)
formed in a housing (25), a third connection passage (83) formed in
the lower bearing member (55), and a connection pipe (84)
connecting the second connection passage (82) to the third
connection passage (83) together form a groove communication
passage (85).
[0138] As illustrated in FIG. 6, the first connection passage (81)
located in an outer circumferential portion (33) of a fixed scroll
(30), and includes an inner vertical communicating path (81a) which
vertically extends in an inner edge part of an outer
circumferential portion (33), a transverse communicating path (81b)
which radially extends in the outer circumferential portion (33),
and an outer vertical communicating path (81c) which vertically
extends in an outer edge part of the outer circumferential portion
(33).
[0139] The inner vertical communicating path (81a) has an upper end
which opens on the upper surface of an end plate (31) and a lower
end which opens in an oil groove (80) formed on a thrust sliding
surface (35). The inner vertical communicating path (81a) has a
female thread (81d) formed on the wall of its upper end part. A rod
member (89) which will be detailed later is provided in the inner
vertical communicating path (81a), and a head (89d) of the rod
member (89) closes the upper end of the communicating path
(81a).
[0140] The transverse communicating path (81b) radially outwardly
extends from a point located immediately below the female thread
(81d) of the inner vertical communicating path (81a), and has an
outer end which opens on the outer circumferential surface of the
fixed scroll (30). The opening of the outer end of the transverse
communicating path (81b) is closed with a plug member.
[0141] The outer vertical communicating path (81c) extends
downwardly from a point located slightly inward relative to the
outer end of the transverse communicating path (81b), and has a
lower end which opens on the lower end surface of the fixed scroll
(30).
[0142] Thus, the inner vertical communicating path (81a), the
transverse communicating path (81b), and the outer vertical
communicating path (81c) successively communicate with each other,
and thereby together form the first connection passage (81) which
connects the oil groove (80) to the lower end surface of the fixed
scroll (30).
[0143] The second connection passage (82) vertically extends in an
outer circumferential part of the housing (25). An upper end of the
second connection passage (82) opens on the upper end surface of
the housing (25) and corresponds to the outer vertical
communicating path (81c) of the first connection passage (81), and
thereby causes the second connection passage (82) to communicate
with the first connection passage (81). On the other hand, a lower
end of the second connection passage (82) opens on the lower end
surface of the housing (25). The second connection passage (82) has
a diameter which is slightly larger than that of the outer vertical
communicating path (81c) of the first connection passage (81). The
second connection passage (82) includes, in a lower end part, a
smaller diameter section which has a diameter slightly smaller than
the diameter of the other part. As will be detailed later, an upper
end part (84a) of the connection pipe (84) and an upper part (91b)
of a coupling pipe (91) are pressed into the smaller diameter
section. With this configuration, the second connection passage
(82) connects the first connection passage (81) to the connection
pipe (84).
[0144] As illustrated in FIG. 7, the third connection passage (83)
includes an inner vertical communicating path (83a) which
vertically extends in the central cylindrical portion (56) of the
lower bearing member (55), a transverse communicating path (83b)
which radially extends from the central cylindrical portion (56) to
enter an arm (57), and an outer vertical communicating path (83c)
which vertically extends in an outer edge part of the arm (57).
[0145] The inner vertical communicating path (83a) has an upper end
which is connected to the recess and opens below the rolling
bearing (54) provided in the recess, and a lower end which opens at
the lower end of the central cylindrical portion (56) located in an
oil reservoir (18). The inner vertical communicating path (83a) has
a female thread (83d) formed on the wall of its upper end part.
Another rod member (89) which will be detailed later is provided in
the inner vertical communicating path (83a), and the head (89d) of
the rod member (89) closes the upper end of the inner vertical
communicating path (83a).
[0146] The transverse communicating path (83b) radially outwardly
extends from a point located immediately below the female thread
(83d) formed in the upper end part of the inner vertical
communicating path (83a), and has an outer end which opens on the
outer circumferential surface of the arm (57). The opening of the
outer end of the transverse communicating path (83b) is closed with
a plug member. The outer vertical communicating path (83c) has an
upper end which opens on the upper end surface of the arm (57), and
a lower end which opens on the lower end surface of the arm (57).
The outer vertical communicating path (83c) communicates with the
transverse communicating path (83b) at a point located slightly
inward relative to the outer end of the transverse communicating
path (83b).
[0147] A lower end part (84b) of the connection pipe (84) is
inserted in an upper part of the outer vertical communicating path
(83c), whose lower end opening is closed with a plug member. The
outer vertical communicating path (83c) has, in its upper end part,
a larger diameter section which has a diameter larger than that of
a main middle part of the communicating path (83c). In the larger
diameter section, the upper half has a diameter which is further
larger than that of the lower half. A projection (93a) of a
pressing member (93) is inserted in the upper half, and an O-ring
(92) is provided in the lower half.
[0148] The pressing member (93) is a plate-like piece of metal
having a penetration hole (93b) through which the connection pipe
(84) penetrates and a bolt hole (93c) through which a bolt
penetrates. The pressing member (93) has a projection (93a) which
continues from the peripheral wall of the penetration hole (93b)
and projects downwardly relative to the other part of the pressing
member (93). The pressing member (93) is fastened to the a (57) of
the lower bearing member (55) with the bolt penetrating through the
bolt hole (93c) in such a manner that the projection (93a)
penetrates the larger diameter section of the outer vertical
communicating path (83c) while pressing the O-ring (92). The
pressing member (93) as described above presses the O-ring (92),
through which the connection pipe (84) penetrates, against the
outer vertical communicating path (83c). In this manner, sealing
between the inner space of the casing (15) and the outer vertical
communicating path (83c) is accomplished.
[0149] Thus, the inner vertical communicating path (83a), the
transverse communicating path (83b), and the outer vertical
communicating path (83c) successively communicate with each other,
and thereby together form the third connection passage (83) which
connects the oil reservoir (18) to the connection pipe (84).
[0150] The connection pipe (84) is a resin pipe made of a resin
material. As illustrated in FIG. 8, in the connection pipe (84),
the upper end part (84a) has a diameter which is larger than that
of a main middle part whereas the lower end part (84b) has a
diameter which is smaller than that of the main middle part. A
lower part (91a) of the coupling pipe (91) which is made of
stainless steel is pressed into the upper end part (84a) having the
larger diameter.
[0151] In the coupling pipe (91), the lower part (91a) located
lower relative to the axial midpoint has a diameter which is
smaller than that of the upper part (91b) located upper relative to
the axial midpoint. Specifically, the lower part (91a) of the
coupling pipe (91) has an outside diameter which is slightly larger
than an inside diameter of the upper end part (84a) of the
connection pipe (84), and is slightly smaller than an outside
diameter of the upper end part (84a) of the connection pipe (84).
On the other hand, the upper part (91b) has an outside diameter
which is substantially equal to the outside diameter of the upper
end part (84a) of the connection pipe (84).
[0152] As illustrated in FIG. 6, the lower part (91a) of the
coupling pipe (91) is pressed into the upper end part (84a) of the
connection pipe (84), and the upper end part (84a) is pressed into
the smaller diameter section located in the lower end part of the
second connection passage (82). Accordingly, the upper end part
(84a) of the connection pipe (84) and the upper part (91b) of the
coupling pipe (91) are in contact with wall of the smaller diameter
section in the lower end part of the second connection passage
(82). Consequently, sealing between the inner space of the casing
(15) and the second connection passage (82) is accomplished by the
connection pipe (84) and the coupling pipe (91). In this manner,
the second connection passage (82) communicates with the connection
pipe (84) through the coupling pipe (91) without communicating with
the inner space of the casing (15).
[0153] On the other hand, as illustrated in FIG. 7, the lower end
part (84b) of the connection pipe (84) penetrates an upper part of
the outer vertical communicating path (83c) of the third connection
passage (83). Specifically, the lower end part (84b) of the
connection pipe (84) penetrates through the penetration hole (93b)
of the pressing member (93) and the O-ring (92), and the tip of the
connection pipe (84) is positioned near the point where the outer
vertical communicating path (83c) and the transverse communicating
path (83b) of the third connection passage (83) communicate with
each other. This configuration in which the connection pipe (84)
penetrates through the O-ring (92) and then in the outer vertical
communicating path (83c) of the third connection passage (83)
allows the third connection passage (83) to communicate with the
inside of the connection pipe (84) without communicating with the
inner space of the casing (15).
[0154] As shown enlarged in FIGS. 6 and 7, each of the rod members
(89) provided in the inner vertical communicating path (81a) of the
first connection passage (81) and the inner vertical communicating
path (83a) of the third connection passage (83) includes a body
part (89a), a smaller diameter part (89b), a screw part (89c), and
the head (89d), all of which are continuously formed from the tip
toward the base of the rod member.
[0155] The body part (89a) is a rod-like member in a circular
column shape and has a spiral thin groove (89e) with a width of
about 0.5-1.0 mm formed on its outer circumference. The body part
(89a) configured in this manner causes a narrow spiral channel to
be formed between the wall of each of the inner vertical
communicating paths (81a, 83a) and the body part (89a). The smaller
diameter part (89b) has a diameter smaller than the diameters of
the inner vertical communicating paths (81a, 83a) and causes an
annular passage to be formed between the wall of each of the inner
vertical communicating paths (81a, 83a) and the smaller diameter
part (89b). The inner end of each of the transverse communicating
paths (81b, 83b) opens in the associated annular passage. The screw
part (89c) is a rod-like member in a circular column shape, and has
on its outer circumference a male thread which is threadedly
engaged with the female threads (81d, 83d) formed in the upper end
parts of the inner vertical communicating paths (81a, 83a). The
head (89d) is in a disc shape having a diameter larger than the
diameters of the inner vertical communicating paths (81a, 83a).
[0156] The rod member (89) as described above causes, by means of
the body part (89a), the narrow spiral channel be formed in each of
the inner vertical communicating paths (81a, 83a) where the rod
member (89) is disposed. The narrow spiral channel formed on the
outer circumference of the rod member (89) controls flow rate of
the refrigeration oil which has flowed into each of the inner
vertical communicating paths (81a, 83a). That is, each of the rod
members (89) serves as a throttle for controlling the flow rate of
the refrigeration oil in the groove communication passage (85).
[0157] In this embodiment, the groove communication passage (85),
which includes the first, second, third connection passages (81-83)
and the connection pipe (84), connects the oil groove (80) only to
the oil reservoir (18) in the casing (15). Accordingly, in a manner
similar to Embodiment 1, this embodiment is also configured such
that an oil supply passage (77) formed in the driving shaft (60) is
not in communication with the oil groove (80) formed on the fixed
scroll (30). Thus, a bearing oil supply passage (70) is not in
communication with the oil groove (80), and the refrigeration oil
is caused to flow through the groove communication passage (85)
only by a pressure difference between the oil reservoir (18) in the
casing (15) and the oil groove (80).
[0158] Specifically, the refrigeration oil in the oil reservoir (8)
flows through the groove communication passage (85), by passing
consecutively through the third connection passage (83), the
connection pipe (84), the second connection passage (82), and the
first connection passage (81), and then, is supplied to the oil
groove (80). Consequently, the oil groove (80) is filled with the
refrigeration oil with a high pressure, and the refrigeration oil
in the oil groove (80) gradually flows out to enter a clearance
between the thrust sliding surface (45) and the thrust sliding
surface (35) to be used to lubricate the thrust sliding surfaces
(35, 45).
[0159] Thus, also in this embodiment, it is ensured that the
refrigeration oil is supplied to the clearance between the thrust
sliding surface (45) and the thrust sliding surface (35).
Accordingly, even in a state where the orbiting scroll (40) is
strongly pressed against the fixed scroll (30), the friction force
generated between the thrust sliding surface (45) and the thrust
sliding surface (35) is not allowed to become excessively
strong.
[0160] Further, the groove communication passage (85) of this
embodiment is also equipped with the throttles, i.e. the rod
members (89), for controlling the flow rate of the refrigeration
oil. Accordingly, also in this embodiment, even in a state where
the orbiting scroll (40) has been tilted and the clearance between
the thrust sliding surface (45) and the thrust sliding surface (35)
has increased, the flow rate of the refrigeration oil having flowed
into the groove communication passage (85) is controlled by the
narrow spiral channels formed on the outer circumferences of the
rod members (89).
[0161] Thus, also in this embodiment, even in a state where the
orbiting scroll (40) has been tilted, the flow rate of the
refrigeration oil flowing from the groove communication passage
(85) into the oil groove (80) and the pressure of the oil groove
(80) are kept low. Accordingly, even when the orbiting scroll (40)
is tilted during operation of the compression mechanism (20), the
pressure acting on the thrust sliding surfaces (35, 45) is kept
low, and the force separating the orbiting scroll (40) from the
fixed scroll (30) is not allowed to become excessively strong. On
the other hand, pressing force acts on the orbiting scroll (40) to
press the orbiting scroll (40) against the fixed scroll (30).
Accordingly, the orbiting scroll (40) which has been tilted during
operation of the compression mechanism (20) quickly restores the
original position by receiving the pressing force. Consequently,
this embodiment provides advantages similar to those of Embodiment
1.
[0162] Further, according to this embodiment, the throttle which
controls the flow rate of the refrigeration oil in the groove
communication passage (85) can be easily provided simply by
inserting into the groove communication passage (85) the rod member
(89) having the spiral groove (89e) formed on the outer
circumference. Furthermore, the cross-sectional area of the groove
communication passage (85) can be easily varied simply by changing
the cross-sectional shape of the spiral groove (89e) formed on the
outer circumference of the rod member (89). That is, use of the rod
member (89) as the throttle increases the degree of freedom of
design and makes it easy to change the design.
[0163] When using the rod member (89), which has the spiral groove
(89e) on the outer circumference as described above, as the
throttle for controlling the flow rate of the refrigeration oil in
the groove communication passage (85), the narrow channel formed
with the spiral groove (89e) needs to be long to some extent in
order o obtain a sufficient throttle effect. Increasing the length
of the narrow channel by using a longer rod member (89), however,
requires a longer space in which the longer rod member (89) is
placed. In addition, installation of the longer rod member (89) may
require much time and effort.
[0164] To address this problem, in this embodiment, a plurality of
the rod members (89) serving as the throttles are provided in a
plurality of locations of the groove communication passage (85).
Accordingly, it is possible to increase the total length of the
narrow channels by using the rod members (89) each of which is
short, and the flow rate of the lubricating oil in the groove
communication passage (85) can be sufficiently controlled. In other
words, providing the plurality of rod members (89) in the plurality
of locations of the groove communication passage (85) makes it
possible to reduce the length of each of the rod members (89).
Consequently, it is unnecessary to ensure long spaces for
installation of the rod members (89), and the rod members (89) can
be easily installed.
[0165] Furthermore, in this embodiment, both of the lower bearing
member (55) and the fixed scroll (30) include the connection
passages serving as the communicating paths which form part of the
groove communication passage (85), and are provided with the
throttles. Specifically, each of the third connection passage (83)
in the lower bearing member (55) and the first connection passage
(81) in the fixed scroll (30) is provided with the rod member (89)
serving as the throttle. Accordingly, even if each of rod members
(89) and each of the communicating paths (i.e. the third connection
passage (83) and the first connection passage (81)) is short, the
narrow channels can have a large length in total. Consequently, the
flow rate of the refrigeration oil in the groove communication
passage (85) can be sufficiently controlled. In other words,
designing each of the lower bearing member (55) and the fixed
scroll (30) to include the associated communicating path (i.e. the
third connection passage (83) or the first connection passage (81))
and the associated rod member (89) provided in the associated
communicating path enables reduction of the length of each of the
rod members (89). Consequently, it is unnecessary to ensure long
spaces for installation of the rod members (89), and the rod
members (89) can be easily installed.
[0166] According to this embodiment, the connection pipe (84)
forming part of the groove communication passage (85) is provided
between the casing (15) and a motor (50). If the connection pipe
(84) provided on a side of the motor (50) was a metal pipe, it
would be necessary to space the connection pipe (84) from the motor
(50) at a distance which ensures insulation, and the diameter of
the casing (15) would need to be increased in accordance with the
distance between the connection pipe (84) and the motor (50). In
this embodiment, however, the connection pipe (84) provided on a
side of the motor (50) is a resin pipe made of a resin material.
Accordingly, it is possible to ensure insulation without distancing
the connection pipe (84) from the motor (50). It is consequently
possible to design the casing (15) to have a smaller diameter, and
to downsize the scroll compressor.
[0167] The connection pipe (84) may he a metal pipe having only an
outer circumferential surface coated with a resin material, instead
of the pipe entirely made of a resin material as described
above.
[0168] Note that the foregoing embodiments have been set forth
merely for purposes of substantially preferred examples, and are
not intended to limit the scope, applications, and use of the
present disclosure.
INDUSTRIAL APPLICABILITY
[0169] As described above, the present disclosure is useful for the
scroll compressors for compressing, e.g., a refrigerant.
DESCRIPTION OF REFERENCE CHARACTERS
[0170] 10 Scroll compressor
15 Casing
[0171] 18 Oil reservoir 20 Compression mechanism 30 Fixed scroll 35
Thrust sliding surface of fixed scroll 40 Orbiting scroll 41 End
plate of orbiting scroll (End plate) 45 Thrust sliding surface 60
Driving shaft 70 Oil supply passage (Bearing oil supply passage) 75
Oil supply pump 80 Oil groove 85 Groove communication passage 87
Capillary tube (Throttle)
* * * * *