U.S. patent application number 14/758174 was filed with the patent office on 2015-11-19 for scroll compressor.
The applicant listed for this patent is DAIKIN INDUSTRIES, LTD.. Invention is credited to Yoshitomo TSUKA.
Application Number | 20150330390 14/758174 |
Document ID | / |
Family ID | 51020328 |
Filed Date | 2015-11-19 |
United States Patent
Application |
20150330390 |
Kind Code |
A1 |
TSUKA; Yoshitomo |
November 19, 2015 |
SCROLL COMPRESSOR
Abstract
A scroll compressor includes a casing, an electric motor housed
in the casing, a drive shaft driven by the electric motor, a
compression mechanism, a housing and an oil transfer mechanism. The
compression mechanism has movable and fixed scrolls. The movable
scroll has an engaging portion engaging one end of the drive shaft.
The housing includes a bearing supporting the drive shaft and a
receiving portion receiving the engaging portion. The oil transfer
mechanism transfers oil in an oil reservoir of the casing. The
drive shaft is provided. with an oil supply passage supplying the
oil transferred by the oil transfer mechanism to a sliding portion
of the engaging portion. The housing is provided with a recess
provided on a bottom of the receiving portion and an oil supply
channel delivering the oil in the recess to a. sliding portion of
the compression mechanism.
Inventors: |
TSUKA; Yoshitomo;
(Sakai-shi, Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DAIKIN INDUSTRIES, LTD. |
Osaka-shi, Osaka |
|
JP |
|
|
Family ID: |
51020328 |
Appl. No.: |
14/758174 |
Filed: |
December 10, 2013 |
PCT Filed: |
December 10, 2013 |
PCT NO: |
PCT/JP2013/007242 |
371 Date: |
June 26, 2015 |
Current U.S.
Class: |
418/55.1 |
Current CPC
Class: |
F04C 29/0085 20130101;
F04C 18/0215 20130101; F04C 29/028 20130101; F04C 23/008 20130101;
F04C 29/023 20130101 |
International
Class: |
F04C 29/02 20060101
F04C029/02; F04C 29/00 20060101 F04C029/00; F04C 18/02 20060101
F04C018/02 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 28, 2012 |
JP |
2012-288807 |
Claims
1. A scroll compressor, comprising: a casing; an electric motor
housed in the casing; a drive shaft driven by the electric motor; a
compression mechanism having a movable scroll and a fixed scroll,
the movable scroll having an engaging portion with which one end of
the drive shaft engages, and the movable scroll rotating
eccentrically relative to the drive shaft; a housing including a
bearing supporting the drive shaft, and a receiving portion
receiving the engaging portion; and an oil transfer mechanism
transferring oil in an oil reservoir of the casing, the drive shaft
being provided with an oil supply passage supplying the oil
transferred by the oil transfer mechanism to a sliding portion of
the engaging portion, and the housing being provided with a recess
provided on a bottom of the receiving portion, the oil accumulating
in the recess after lubricating the sliding portion of the engaging
portion, and an oil supply channel delivering the oil in the recess
to a sliding portion of the compression mechanism, the recess being
configured as an annular groove surrounding an entire periphery of
the bearing.
2. (canceled)
3. A scroll compressor comprising: a casing; an electric motor
housed in the casing; a drive shaft driven by the electric motor; a
compression mechanism having a movable scroll and a fixed scroll,
the movable scroll having an engaging portion with which one end of
the drive shaft engages and the movable scroll rotating
eccentrically relative to the drive shaft; a housing including a
bearing supporting the drive shaft, and a receiving portion
receiving the engaging portion; and an oil transfer mechanism
transferring oil in an oil reservoir of the casing, the drive shaft
being provided with an oil supply passage supplying the oil
transferred by the oil transfer mechanism to a sliding portion of
the engaging portion, and the housing being provided with a recess
provided on a bottom of the receiving portion. the oil accumulating
in the recess after lubricating the sliding portion of the engaging
portion, an oil supply channel delivering the oil in the recess to
a sliding portion of the compression mechanism, and an oil exhaust
channel delivering the oil in the receiving portion to the oil
reservoir, an inlet port of the oil exhaust channel being opened to
an inside of the recess.
4. (canceled)
5. (canceled)
6. The scroll compressor of claim 3, wherein the inside of the
recess is partitioned, by a partition member extending from a
bottom of the recess to an open end of the recess, into a first
space which communicates with an inlet port (90a) of the oil supply
channel and a second space which communicates with the inlet port
of the oil exhaust channel, and the first space has a larger volume
than the second space.
7. (canceled)
Description
TECHNICAL FIELD
[0001] The present invention relates to a scroll compressor, and
more particularly relates to a measure to supply oil to a sliding
portion of a compression mechanism.
BACKGROUND ART
[0002] Scroll compressors having a fixed scroll and a movable
scroll for compressing a fluid therebetween have been known and
widely used in, e.g., a refrigerating apparatus.
[0003] Patent Document 1 discloses a scroll compressor of this
type. The scroll compressor has an electric motor housed in a
casing, and a drive shaft driven in rotation by the electric motor.
One end of the drive shaft is engaged with an engaging portion of
an end plate of the movable scroll. The rotation of the drive shaft
being driven by the electric motor causes the movable scroll to
rotate eccentrically relative to the fixed scroll, which gradually
reduces the volume of a compression chamber between these scrolls,
thereby compressing the fluid in the compression chamber.
[0004] Further, a housing which rotatably receives the drive shaft
is fixed to the inner peripheral surface of the casing. The housing
has a receiving chamber, arranged in its upper middle portion, for
receiving the drive shaft and the engaging portion of the movable
scroll. An oil pump is provided at a lower end portion of the drive
shaft in order to suck up oil from an oil reservoir at the bottom
of the casing. The oil sucked up by the oil pump with the rotation
of the drive shaft flows upward through an oil passage in the drive
shaft. The oil is then supplied to a bearing of the drive shaft and
the sliding portion between the drive shaft and the engaging
portion of the movable scroll, and thereafter into the receiving
chamber. The oil accumulated in the receiving chamber sequentially
flows through an oil passage 44a extending radially outward from
the receiving chamber, and an oil passage 44b extending upward from
the outlet of the oil passage 44a, and is then supplied to a
sliding portion (a sliding portion of a thrust surface) of the
compression mechanism. Thus, the scroll compressor of Patent
Document 1 lubricates the sliding portion of the thrust surface of
the compression mechanism, using the oil which has been used to
lubricate the sliding portion between the drive shaft and the
engaging portion of the movable scroll.
CITATION LIST
Patent Document
[0005] Patent Document 1: Japanese Unexamined Patent Publication
No, 2001-214872
SUMMARY OF THE INVENTION
Technical Problem
[0006] The scroll compressor disclosed in Patent Document 1 always
needs to store a certain amount of oil in the receiving chamber so
that the oil in the receiving chamber can be supplied to the
sliding portion of the compression mechanism with reliability.
However, such storage of a certain amount of oil in the receiving
chamber will cause the drive shaft or engaging portion housed in
the receiving chamber to be soaked in the oil. This increases a
frictional resistance between the drive shaft or the engaging
portion and the oil during the rotation of the drive shaft, thereby
increasing churning loss and the motive energy of the electric
motor.
[0007] In view of the foregoing background, it is therefore an
object of the present invention to provide a scroll compressor that
can reduce such oil churning loss in the receiving chamber.
Solution to the Problem
[0008] A first aspect of the invention is directed to a scroll
compressor including: a casing (15); an electric motor (50) housed
in the casing (15); a drive shaft (60) driven by the electric motor
(50); a compression mechanism (20) which has a movable scroll (40)
and a fixed scroll (30), the movable scroll (40) having an engaging
portion (43), with which one end of the drive shaft (60) engages,
and rotating eccentrically relative to the drive shaft (60); a
housing (25) including a bearing (28) which supports the drive
shaft (60), and a receiving portion (26) which receives the
engaging portion (43); and an oil transfer mechanism (75) which
transfers oil in an oil reservoir (18) of the casing (15). The
drive shaft (60) is provided with an oil supply passage (70) which
supplies the oil transferred by the oil transfer mechanism (75) to
a sliding portion (44) of the engaging portion (43). In this scroll
compressor, the housing (25) is provided with a recess (78) which
is provided on a bottom (26a) of the receiving portion 115 (26),
and in which the oil accumulates after lubricating the sliding
portion (44) of the engaging portion (43), and an oil supply
channel (90) which delivers the oil in the recess (78) to a sliding
portion (35, 45) of the compression mechanism (20).
[0009] In the first aspect of the invention, one end of the drive
shaft (60) engages with the engaging portion (43) of the movable
scroll (40), thereby coupling the drive shaft (60) and the movable
scroll (40). Rotation of the drive shaft (60) being driven by the
electric motor (50) causes the movable scroll (40) to rotate
eccentrically relative to the fixed scroll (30), which reduces the
volume of a compression chamber between the fixed scroll (30) and
the movable scroll (40), thereby compressing the fluid in the
compression chamber.
[0010] The oil transfer mechanism (75) supplies the oil in the oil
reservoir (18) of the casing (15) to the sliding portion (44)
between the drive shaft (60) and the engaging portion (43) via the
oil supply passage (70). As a result, the sliding portion (44) is
lubricated with the oil to cause a decrease in sliding friction.
The oil used to lubricate the sliding portion (44) of the engaging
portion (43) flows into the receiving portion (26) that receives
the engaging portion (43). Since the present invention provides a
recess (78) on the bottom of the receiving portion (26), the oil
which has flowed out falls down into the recess (78). This reduces
the possibility of the oil accumulating in the receiving portion
(26) so much as to reach the vicinity of the engaging portion (43).
As a result, the oil churning loss is reduced at the engaging
portion (43) during its rotation.
[0011] The oil which has fallen down into the recess (78) is led to
the sliding portion (35, 45) of the compression mechanism (20)
through the oil supply channel (90). Since the recess (78) is
located at a lower level than the bottom of the receiving portion
(26), the oil in the receiving portion (26) is successively
supplied into the recess (78). This allows for a. reliable supply
of the oil in the recess (78) to the sliding portion (35, 45) of
the compression mechanism (20).
[0012] A second aspect of the invention is an embodiment of the
first aspect of the invention. In the second aspect, the recess
(78) is configured as an annular groove (78) surrounding an entire
periphery of the bearing (28),
[0013] The recess of the second aspect is configured as an annular
groove (78) surrounding an entire periphery of the bearing (28) of
the drive shaft (60). The annular groove surrounding the entire
periphery of the bearing (28) decreases the elastic modulus of a
portion of the housing (25) between the annular groove (78) and the
bearing (28). Thus, this portion is easily deformed along the outer
peripheral surface of the drive shaft (60) even if the axial center
of the drive shaft (60) inclines during the rotation of the drive
shaft (60). This prevents the outer peripheral surface of the drive
shaft (60) from partially contacting with the bearing (28), thereby
reducing bearing load on the bearing (28).
[0014] A third aspect of the invention is an embodiment of the
first or second aspect of the invention. In the third aspect, the
housing (25) is provided with an oil exhaust channel (80) which
delivers the oil in the receiving portion (26) to the oil reservoir
(18).
[0015] In the third aspect of the invention, part of the oil which
has fallen down into the receiving portion (26) after lubricating
the sliding portion (44) of the engaging portion (43) returns to
the oil reservoir (18) through the oil exhaust channel (80). This
prevents a shortage of oil in the oil reservoir (18). Further, a
rise in the oil level of the receiving portion (26) is prevented by
returning the oil in the receiving portion (20 to the oil reservoir
(18) through the oil exhaust channel (80). Thus, the engaging
portion (43) is prevented from being soaked in the oil, which
reduces the oil churning loss at the engaging portion (43) during
its rotation.
[0016] A fourth aspect of the invention is an embodiment of the
third aspect of the invention. In the fourth aspect, an inlet port
(80a) of the oil exhaust channel (80) is opened to an inner space
of the receiving portion (26) so as to be level with the bottom
(26a) of the receiving portion (26).
[0017] In the fourth aspect of the invention, the inlet port (80a)
of the oil exhaust channel (80) is arranged to be level with the
bottom (26a) of the receiving portion (26). Thus, the oil which has
overflowed from the recess (78) is immediately introduced to the
oil exhaust channel (80). The rise in the oil level in the
receiving portion (26) is therefore prevented with reliability.
[0018] A fifth aspect of the invention is an embodiment of the
third aspect of the invention. In the fifth aspect, an inlet port
(80a) of the oil exhaust channel (80) is opened to inside of the
recess (78).
[0019] In the fifth aspect of the invention, part of the oil which
has fallen down into the recess (78) from the receiving portion
(26) returns to the oil reservoir (18) through the oil exhaust
channel (80). Thus, the oil in the recess (78) is prevented from
overflowing into the receiving portion (26), thereby preventing the
rise in the oil level in the receiving portion (26) with
reliability.
[0020] A sixth aspect of the invention is an embodiment of the
fifth aspect of the invention. In the sixth aspect, the inside of
the recess (78) is partitioned, by a partition member (100)
extending from a bottom of the recess (78) to an open end of the
recess (78), into a first space (S1) which communicates with an
inlet port (90a) of the oil supply channel (90), and a second space
(S2) which communicates with the inlet port (80a) of the oil
exhaust channel (80), and the first space (S1) has a larger volume
than the second space (S2).
[0021] In the sixth aspect of the invention, the inside of the
recess (78) is partitioned into a first space (S1) and a second
space (S2) by a partition member (100). The volume of the first
space (S1) that communicates with the oil supply channel (90) is
larger than the volume of the second space (52) that communicates
with the oil exhaust channel (80). This means that the amount of
the oil falling down into the recess (78) after having been used to
lubricate the sliding portion (44) of the engaging portion (43) is
greater in the first space (S1) than in the second space (S2).
Thus, the present invention allows for storing a sufficient amount
of oil to be supplied to the sliding portion (35, 45) of the
compression mechanism (20) through the oil supply channel (90).
[0022] A seventh aspect of the invention is an embodiment of any
one of the third to sixth aspects of the invention. In the seventh
aspect, the inlet port (90a) of the oil supply channel (90) is
located at a lower level than the inlet port (80a) of the oil
exhaust channel (80).
[0023] In the seventh aspect of the invention, the inlet port (90a)
of the oil supply channel (90) is located at a lower level than the
inlet port (80a) of the oil exhaust channel (80). Thus, if the oil
level is between the inlet port (90a) of the oil supply channel
(90) and the inlet port (80a) of the oil exhaust channel (80), this
oil is led only to the oil supply channel (90). On the other hand,
if the oil level is higher than the inlet port (80a) of the oil
exhaust channel (80), this oil is led to both of the oil supply
channel (90) and the oil exhaust channel (80). That is, according
to the present invention, the oil which has flowed out into the
receiving portion (26) is supplied preferentially to the oil supply
channel (90) rather than to the oil exhaust channel (80). This
allows for reliable lubrication of the sliding portion (35, 45) of
the compression mechanism (20).
ADVANTAGES OF THE INVENTION
[0024] According to the present invention, the recess (78) is
provided on the bottom (26a) of the receiving portion (26). This
allows for delivering the oil used to lubricate the sliding portion
(44) of the engaging portion (43) to the recess (78). As a result,
the possibility of the engaging portion (43) being soaked in the
oil is reduced in the receiving portion (26), thereby reducing the
oil churning loss at the engaging portion (43) during its
rotation.
[0025] If the oil were agitated by the engaging portion (43), a
compressed fluid could be mixed with this oil, or the oil might
turn into a mist. As a result, it would be difficult for the oil to
return to the oil reservoir (18) due to its own weight, causing a
shortage of oil in the oil reservoir (18). On the other hand, in
the present invention, the possibility of the engaging portion (43)
being soaked in the oil is reduced as mentioned above, which
therefore prevents the compressed fluid from being mixed with the
oil, and also prevents the oil from turning into a mist. Thus, the
oil used to lubricate the sliding portion (44) can immediately
return to the oil reservoir (18), and so-called oil shortage can be
prevented.
[0026] According to the second aspect of the invention, the recess
is configured as an annular groove (78). This prevents partial
contact between the drive shaft (60) and the bearing (28), That is,
in the present invention, the annular groove (78) functions not
only as a recess (78) for accumulating the oil but also as a
so-called elastic groove. This allows for simplifying the device
structure.
[0027] According to the third aspect of the invention, the oil
which has flowed out into the receiving portion (26) returns to the
oil reservoir (18) via the oil exhaust channel (80). This prevents
the engaging portion (43) from being soaked in the oil, thereby
reducing the possibility of the oil being agitated by the engaging
portion (43). In particular, according to the fourth aspect of the
invention, the inlet port (80a) of the oil exhaust channel (80) is
level with the bottom (26a) of the receiving portion (26). Thus,
the oil in the receiving portion (26) can be immediately
discharged. Further, according to the fifth aspect of the
invention, the inlet port (80a) of the oil exhaust channel (80) is
opened to the inside of the recess (78). This prevents the oil in
the recess (78) from overflowing into the receiving portion (26).
As a result, according to the fourth and fifth aspects of the
invention, the rise in the oil level of the receiving portion (26)
is effectively prevented, thereby reducing the possibility of the
oil being agitated by the engaging portion (43) with
reliability.
[0028] According to the sixth aspect of the invention, the inside
of the recess (78) is partitioned into a first space (S1) and the
second space (S2) by a partition member (100), and the first space
(S1) communicating with the oil supply channel (90) has a larger
volume than the second space (S2). This prevents a shortage of the
oil to be supplied from the oil supply channel (90) to the sliding
portion (35, 45) of the compression mechanism (20). As a result,
the sliding portion (35, 45) of the compression mechanism (20) is
lubricated successfully, and the reliability of the scroll
compressor is improved eventually,
[0029] According to the seventh aspect of the invention, the inlet
port (90a) of the oil supply channel (90) is located at a lower
level than the inlet port (80a) of the oil exhaust channel (80).
This prevents a shortage of the oil to be supplied from the oil
supply channel (90) to the sliding portion (35, 45) of the
compression mechanism (20). As a result, the sliding portion (35,
45) of the compression mechanism (20) is lubricated as intended,
and the reliability of the scroll compressor is improved
eventually.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is a vertical cross-sectional view illustrating the
general configuration of a scroll compressor according to an
embodiment.
[0031] FIG. 2 is a vertical cross-sectional view illustrating, on a
larger scale, main parts of a compression mechanism and housing
according to an embodiment.
[0032] FIG. 3 is a horizontal cross-sectional view illustrating the
internal structure of the compression mechanism.
[0033] FIG. 4 is a cross-sectional view taken along the plane X-X
of FIG. 2.
[0034] FIG. 5 illustrates a scroll compressor of a first variation
and corresponds to FIG. 2.
[0035] FIG. 6 is a perspective view illustrating an internal
structure of a central recess in a scroll compressor of a second
variation.
[0036] FIG. 7 is a horizontal cross-sectional view illustrating the
internal structure of the central recess in the scroll compressor
of the second variation.
DESCRIPTION OF EMBODIMENTS
[0037] An embodiment of the present invention will now be described
in detail with reference to the drawings. The following embodiment
is an only preferred example in nature, and is not intended to
limit the scope, applications, and use of the invention.
[0038] An embodiment of the present invention will be described. A
scroll compressor (10) of the present embodiment is a hermetically
sealed compressor. The scroll compressor (10) is connected to a
refrigerant circuit, which performs a refrigeration cycle, to suck
and compress a refrigerant in the refrigerant circuit.
General Configuration for Scroll Compressor
[0039] As illustrated in FIG. 1, the scroll compressor (10) has a
casing (15) which houses, in its inner space, a compression
mechanism (20), an electric motor (50), a lower bearing member
(55), and a drive shaft (60). The casing (15) is a vertically
elongated cylindrical hermetic container. The compression mechanism
(20), the electric motor (50), and the lower bearing member (55)
are arranged in this order from top to bottom in the inner space of
the casing (15). The drive shaft (60) is arranged such that its
axial direction is parallel to the height direction of the casing
(15). The structure of the compression mechanism (20) will be
described later in detail.
[0040] A suction pipe (16) and a discharge pipe (17) are attached
to the casing (15). Both of the suction pipe (16) and the discharge
pipe (17) pass through the casing (15). The suction pipe (16) is
connected to the compression mechanism (20). The discharge pipe
(17) is opened to the inner space of the casing (15) between the
electric motor (50) and the compression mechanism (20).
[0041] The lower bearing member (55) has a central cylindrical
portion (56) and an arm portion (57). Although FIG. 1 illustrates
only one arm portion (57), the lower bearing member (55) actually
has three arm portions (57). The central cylindrical portion (56)
has an approximately cylindrical shape. Each of the arm portions
(57) extends outward from the outer peripheral surface of the
central cylindrical portion (56). The three arm portions (57) of
the lower bearing member (55) are spaced apart from each other at
substantially equal angles. Projecting ends of the respective arm
portions (57) are fixed to the casing (15). A bearing metal (58) is
inserted in the vicinity of an upper end portion of the central
cylindrical portion (56). An auxiliary journal (67) of the drive
shaft (60) to be described later is inserted in, and passes
through, this bearing metal (58). The central cylindrical portion
(56) functions as a journal bearing which supports the auxiliary
journal (67).
[0042] The electric motor (50) has a stator (51) and a rotor (52).
The stator (51) is fixed to the casing (15). The rotor (52) is
arranged coaxially with the stator (51). A main shaft portion (61)
of the drive shaft (60) to be described later is inserted in, and
passes through, this rotor (52). A plurality of core cuts (51a)
extending between both ends of the stator (51) in its axial
direction are formed in the outer peripheral surface of the stator
(51) in order to allow a refrigerant and oil to flow
therethrough.
[0043] The drive shaft (60) includes the main shaft portion (61), a
balance weight portion (62), and an eccentric portion (63). The
balance weight portion (62) is disposed at a halfway point in the
axial direction of the main shaft portion (61). A portion of the
main shaft portion (61) under the balance weight portion (62)
passes through the rotor (52) of the electric motor (50). Another
portion of the main shaft portion (61) over the balance weight
portion (62) functions as a main journal (64), and still another
portion of the main shaft portion (61) under the portion passing
through the rotor (52) functions as the auxiliary journal (67). The
main journal (64) is inserted in, and passes through, a bearing
metal (28) provided inside a central expansion (27) of a housing
(25). The auxiliary journal (67) is inserted in, and passes
through, the bearing metal (58) provided inside the central
cylindrical portion (56) of the lower bearing member (55).
[0044] The eccentric portion (63) is arranged at the upper end of
the drive shaft (60). The eccentric portion (63) has a columnar
shape with a smaller diameter than the main journal (64), and
projects from the upper end surface of the main journal (64). The
axial center of the eccentric portion (63) is parallel to the axial
center of the main journal (64) (i.e., the axial center of the main
shaft portion (61)), and is eccentric with the axial center of the
main journal (64). The eccentric portion (63) in inserted in a
bearing metal (44) provided inside a cylindrical portion (43) of
the movable scroll (40). The cylindrical portion (43) of the
movable scroll (40) functions as an engaging portion with which the
eccentric portion (63) rotatably engages.
[0045] The drive shaft (60) is provided with an oil supply passage
(70). The oil supply passage (70) has one main passage (74) and
three branch passages (71-73). The main passage (74) extends along
the axial center of the drive shaft (60). One end of the main
passage (74) is opened to the bottom end of the main shaft portion
(61), and the other end thereof is opened to the upper end surface
of the eccentric portion (63). A first branch passage (71) is
provided for the eccentric portion (63). The first branch passage
(71) extends outward from the main passage (74) in the radial
direction of the eccentric portion (63), and is opened to the outer
peripheral surface of the eccentric portion (63). A second branch
passage (72) is provided for the main journal (64). The second
branch passage (72) extends outward from the main passage (74) in
the radial direction of the main journal (64), and is opened to the
outer peripheral surface of the main journal (64). A third branch
passage (73) is provided for the auxiliary journal (67). The third
branch passage (73) extends outward from the main passage (74) in
the radial direction of the auxiliary journal (67), and is opened
to the outer peripheral surface of the auxiliary journal (67).
[0046] An oil supply pump (75), which functions as an oil transfer
mechanism, is attached to the lower end of the drive shaft (60).
The oil supply pump (75) is a trochoid pump driven by the drive
shaft (60). The oil supply pump (75) is arranged near the starting
end of the main passage (74) of the oil supply passage (70).
Further, the oil supply pump (75) is provided with an inlet port
(76), opened downward at its lower end, for sucking up the
refrigeration oil, whish is a lubricating oil. The oil supply pump
(75) does not have to be the trochoid pump but may also be any
positive displacement pump driven by the drive shaft (60). Thus,
the oil supply pump (75) may be a gear pump, for example.
[0047] The refrigeration oil, which is a lubricating oil, is
accumulated at the bottom of casing (15). That is, an oil reservoir
(8) is provided at the bottom of the casing (15). As the drive
shaft (60) rotates, the oil supply pump (75) sucks up the
refrigeration oil from the oil reservoir (18) and discharges that
refrigeration oil, which then flows through the main passage (74).
The refrigeration oil flowing through the main passage (74) is
supplied to the lower bearing member (55) and the sliding portion
between the compression mechanism (20) and the drive shaft (60).
Since the oil supply pump (75) is a positive displacement pump, the
flow rate of the refrigeration oil in the main passage (74) is
proportional to .sup.-the rotational speed of the drive shaft
(60).
[0048] As also illustrated in FIG. 2, in the casing (15), a housing
(25) is provided above the electric motor (50). The housing (25)
has a thick disk-like shape, with its outer peripheral edge fixed
to the casing (15). The housing (25) is provided, at its central
portion, with a central recess (26) and an annular projection (29).
The central recess (26) is a columnar depression opened on the
upper surface of the housing (25). The central recess (26)
functions as a receiving portion which receives the cylindrical
portion (43) of the movable scroll (40) and the eccentric portion
(63) of the drive shaft (60). The annular projection (29) surrounds
the outer periphery of the central recess (26), and projects from
the upper surface of the housing (25). The projecting end surface
of the annular projection (29) is a flat surface. The projecting
end surface of the annular projection (29) is provided with a
ring-like recessed groove along its circumferential direction, A
seal member (29a) is fitted in this recessed groove.
[0049] The housing (25) has the central expansion (27). The central
expansion (27) is located under the central recess (26) and expands
downward. The central expansion (27) has a through hole which
vertically runs through the central expansion (27), and into which
the bearing metal (28) is inserted. The main journal (64) of the
drive shaft (60) is inserted in, and passes through, the bearing
metal (28) of the central expansion (27). The central expansion
(27) serves as a journal bearing which supports the main journal
(64).
Configuration for Compression Mechanism
[0050] As also illustrated in FIG. 2, the compression mechanism
(20) includes the fixed scroll (30) and the movable scroll (40).
The compression mechanism (20) is further provided with an Oldham
coupling (24) for regulating the rotational movement of the movable
scroll (40).
[0051] The fixed scroll (30) and the movable scroll (40) are
mounted on the housing (25). The fixed scroll (30) is fixed to the
housing (25) with, e.g., a bolt. On the other hand, the movable
scroll (40) engages with the housing (25) via the Oldham coupling
(24), and is relatively movable with respect to the housing (25).
The movable scroll (40) engages with the drive shaft (60) and
rotates eccentrically.
[0052] The movable scroll (40) is a member comprised of a movable
end plate (41), a movable lap (42), and the cylindrical portion
(43) which arc formed. integrally with each other, The movable end
plate (41) has a disk shape. The movable lap (42) has a spiral wall
shape, and protrudes from the front surface (the upper surface in
FIGS. 1 and 2) of the 115 movable end plate (41). The cylindrical
portion (43) has a cylindrical shape, and protrudes from the back
surface (the lower surface in FIGS. 1 and 2) of the movable end
plate (41).
[0053] The back surface of the movable end plate (41) of the
movable scroll (40) is in sliding contact with the seal member
(29a) provided on the annular projection (29) of the housing (25).
On the other hand, the cylindrical portion (43) of the movable
scroll (40) is inserted in the central recess (26) of the housing
(25) from over the recess (26), The bearing metal (44) is inserted
in the cylindrical portion (43), and functions as a sliding portion
with which the eccentric portion (63) comes into sliding contact.
The eccentric portion (63) of the drive shaft (60) to be described
later is inserted in the bearing metal (44) of the cylindrical
portion (43) from under the bearing metal (44). The cylindrical
portion (43) functions as a journal bearing which slides against
the eccentric portion (63).
[0054] The fixed scroll (30) is a member comprised of a fixed end
plate (31), a fixed lap (32), and an outer peripheral portion (33)
which are formed integrally with each other. The fixed end plate
(31) has a disk shape. The fixed lap (32) has a spiral wall shape,
and protrudes from the front surface (the lower surface in FIGS. 1
and 2) of the fixed end plate (31). The outer peripheral portion
(33) has a thick ring-like shape extending downward from the fixed
end plate (31), and surrounds the fixed lap (32).
[0055] The fixed end plate (31) is provided with a discharge port
(22), The discharge port (22) is a through hole provided around the
center of the fixed end plate (31), and runs through the fixed end
plate (31) in the thickness direction. Further, the suction pipe
(16) is inserted in a portion of the fixed end plate (31) around
its the outer periphery.
[0056] The compression mechanism (20) is provided with a discharge
gas passage (23). The starting end of the discharge gas passage
(23) communicates with the discharge port (22). Although not shown,
the discharge gas passage (23) extends from the fixed scroll (30)
to the housing (25), and the other end thereof is opened to the
lower surface of the housing (25).
[0057] In the compression mechanism (20), the fixed scroll (30) and
the movable scroll (40) are arranged such that the front surface of
the fixed end plate (31) and the front surface of the movable end
plate (41) face each other, and that the fixed lap (32) and the
movable lap (42) engage with each other. Such engagement between
the fixed lap (32) and the movable lap (42) forms a plurality of
compression chambers (21) in the compression mechanism (20).
[0058] Further, in the compression mechanism (20), the movable end
plate (41) of the movable scroll (40) and the outer peripheral
portion (33) of the fixed scroll (30) are in sliding contact with
each other. More particularly, a portion of the front surface (the
upper surface in FIGS. 1 and 2) of the movable end plate (41)
outside the movable lap (42) is a sliding portion (45) of a movable
thrust surface which comes into sliding contact with the fixed
(30). On the other hand, the projecting end surface (the lower
surface in FIGS. 1 and 2) of the outer peripheral portion (33) of
the fixed scroll (30) comes into sliding contact with the sliding
portion (45) of the movable thrust surface of the provable scroll
(40). A portion of the projecting end surface of the outer
peripheral portion (33) which is in sliding contact with the
sliding portion (45) of the movable thrust surface is a sliding
portion (35) of a fixed thrust surface. That is, the sliding
portion (35) of the fixed thrust surface and the sliding portion
(45) of the movable thrust surface form a sliding portion of the
compression mechanism (20).
[0059] As illustrated in FIGS. 2 and 4, the bottom (26a) of the
above-described central recess (26) is provided with an annular
groove (78). The annular groove (78) is configured as a recess
opened upward. The center of the annular groove (78) substantially
coincides with the axial center of the train journal (64), and the
annular groove (78) surrounds entirely the bearing metal (28),
which is a bearing. The annular groove (78) may be implemented as a
so-called "elastic groove". That is, the housing (25) is provided
with a cylindrical projection (79) projecting upward between the e
annular groove (78) and the bearing metal (28). When the main
journal (64) warps radially outward during rotation of the drive
shaft (60), the cylindrical projection (79) elastically deforms
along the main journal (64). This prevents the main journal (64)
from making line contact with the bearing metal (28), i.e.,
so-called partial contact, thereby reducing bearing load on the
bearing metal (28).
[0060] The oil used to lubricate the bearing metal (28) of the main
journal (64) flows through the oil supply passage (70) into the
central recess (26) of the housing (25). The housing (25) is
provided with ate oil exhaust channel (80) for delivering the oil
which has flowed out into the central recess (26) to the oil
reservoir (18), and an oil supply channel (90) for delivering this
oil to the sliding portion (that is, the sliding portion (35) of
the fixed thrust surface and the sliding portion (45) of the
movable thrust surface) of the compression mechanism (20).
[0061] The oil exhaust channel (80) of the present embodiment is
provided for the annular projection (29) of the housing (25). The
oil exhaust channel (80) is comprised of a horizontal hole (81)
which runs radially through a lower end portion of the annular
projection (29), and a vertical hole (82) which extends downward
from the outflow end of the horizontal hole (81). An inlet port
(80a) of the oil exhaust channel (80) is opened to the inside of
the central recess (26). The lower portion of the inlet port (80a)
of the oil exhaust channel (80) is substantially level with the
bottom (26a) of the central recess (26). That is, the inlet port
(80a) of the oil exhaust channel (80) is continuous with the bottom
(26a) of the central recess (26).
[0062] An oil catch plate (83) is arranged under the vertical hole
(82) of the oil exhaust channel (80). The oil catch plate (83) has
an increased-width portion (83a), of which the width increases
upward, and a lower nozzle portion (83b) extending downward from
the increased-width portion (83a). The outflow end (i.e., the lower
end) of the lower nozzle portion (83b) is located in a core cut
(51a) of the stator (51).
[0063] The oil supply channel (90) extends from the central
expansion (27) to the annular projection (29) of the housing (25).
The oil supply channel (90) is comprised of a first oil supply hole
(91) and a second oil supply hole (92), The first oil supply hole
(91) is formed in the housing (25), and extends radially outward,
and obliquely upward, from the annular groove (78). An inlet port
(91a) of the first oil supply hole (91) is opened to the inside of
the annular groove (78). The inlet port (91a) of the first oil
supply hole (91) is located at a lower level than the inlet port
(80a) of the oil exhaust channel (80). Further, the inlet port
(91a) of the first oil supply hole (91) is located at a higher
level than the bottom of the annular groove (78). This structure
prevents waste or any other foreign substances collected at the
bottom of the annular groove (78) from entering the oil supply
channel (90) through the inlet port (91a), and eventually prevents
the oil supply channel (90) from being clogged with such waste or
any other substances.
[0064] The second oil supply hole (92.) runs through the annular
projection (29) of the housing (25) in the axial direction so as to
communicate with the outflow end of the first oil supply hole (91).
A screw member (93) is inserted in, and passes through, the second
oil supply hole (92). The head (93a) of the screw member (93)
closes the lower end of the second oil supply hole (92). The screw
member (93) narrows the flow path of the oil in the second oil
supply hole (92). That is, the screw member (93) functions as a
pressure reducing mechanism (a throttle mechanism) that reduces the
pressure of the oil flowing through the second oil supply hole
(92).
[0065] As illustrated in FIGS. 2 and 3, the outer peripheral
portion (33) of the fixed scroll (30) is provided with an oil
communication passage (94) which communicates with the second oil
supply hole (92), and an oil groove (95) which communicates with
the oil communication passage (94). The inflow end of the oil
communication passage (94) is connected to the second oil supply
hole (92) inside the housing (25). The outflow end of the oil
communication passage (94) is opened to the sliding portion (45) of
the movable thrust surface of the movable scroll (40). The oil
groove (95) is a recessed groove provided on the sliding portion
(35) of the fixed thrust surface of the outer peripheral portion
(33), and has a ring-like shape surrounding the fixed lap (32). The
oil groove (95) communicates with the outflow end of the oil
communication passage (94).
Operation
[0066] Operation of the scroll compressor (10) will be
described.
Operation of Compressing Refrigerant
[0067] In the scroll compressor (10), the energization of the
electric motor (50) causes the drive shaft (60) to rotate the
movable scroll (40). Since the Oldham coupling (24) regulates the
rotational movement of the movable scroll (40), the movable scroll
(40) does not rotate on its own axis but only revolves around.
[0068] When the movable scroll (40) revolves around, a low-pressure
gas refrigerant which has flowed into the compression mechanism
(20) through the suction pipe (16) is sucked into the compression
chamber (21) from around outer peripheral edges of the fixed lap
(32) and the movable lap (42). Further revolution of the movable
scroll (40) disconnects the compression chamber (21) from the
suction pipe (16), thereby closing the compression chamber (21).
The compression chamber (21) then moves along the fixed lap (32)
and the movable lap (42) toward their inner peripheral edges. In
the course of this movement, the volume of the compression chamber
(21) gradually decreases, thus compressing the gas refrigerant in
the compression chamber (21).
[0069] As the volume of the compression chamber (21) gradually
decreases with the movement of the movable scroll (40), the
compression chamber (21) comes to communicate with the discharge
port (22) in the end. The refrigerant compressed in the compression
chamber (21) (that is, a high-pressure gas refrigerant) flows into
the discharge gas passage (23) through the discharge port (22), and
is then discharged into the inner space of the casing (15). In the
inner space of the casing (15), the high-pressure gas refrigerant
discharged from the compression mechanism (20) is once guided to
below the stator (51) of the electric motor (50), and then flows
upward through a gap between the rotor (52) and the stator (51) and
other regions. Thereafter, the high-pressure gas refrigerant flows
out of the casing (15) through the discharge pipe (17).
[0070] The high-pressure gas refrigerant discharged from the
compression mechanism (20) circulates through the inner space of
the casing (15) under the housing (25), where the pressure is
substantially equal to the pressure of the high-pressure gas
refrigerant. This means that the pressure of the refrigeration oil
accumulated in the oil reservoir (18) in the casing (15), too, is
substantially equal to that of the high-pressure gas
refrigerant.
[0071] On the other hand, although not shown, the inner space of
the casing (15) over the housing (25) communicates with the suction
pipe (16), and has almost as much pressure as the low-pressure gas
refrigerant to be sucked into the compression mechanism (20). This
means that in the compression mechanism (20), a space around the
outer periphery of the movable end plate (41) of the movable scroll
(40), too, has almost as much pressure as the low-pressure gas
refrigerant.
Oil Supply Operation at Sliding Portion
[0072] During the operation of the scroll compressor (10), the
rotating drive shaft (60) drives the oil supply pump (75), thereby
sucking up the refrigeration oil accumulated at the bottom of the
casing (15) to the main passage (74) of the oil supply passage
(70). Part of the refrigeration oil flowing through the main
passage (74) flows into the branch passages (71-73), and the rest
flows out of the main passage (74) through its upper end. The oil
(the refrigeration oil) which has flowed into the third branch
passage (73) is supplied to a gap between the auxiliary journal
(67) and the bearing metal (58), and is used to lubricate and cool
the auxiliary journal (67) and the bearing metal (58). The oil
which has flowed into the second branch passage (72) is supplied to
a gap between the main journal (64) and the bearing metal (28), and
is used to lubricate and cool the main journal (64) and the bearing
metal (28).
[0073] The oil which has flowed into the first branch passage (71)
is supplied to a gap between the eccentric portion (63) and the
bearing metal (44), and is used to lubricate and cool the eccentric
portion (63) and the bearing metal (44). The oil used to lubricate
the bearing metal (44) flows out into the central recess (26).
[0074] If this oil used to lubricate the bearing metal (44) is
accumulated in the central recess (26), the cylindrical portion
(43) of the movable scroll (40) may be soaked in the oil. If the
cylindrical portion (43) performs the eccentric rotational movement
a number of times in such a state, the oil in the central recess
(26) constitutes a resistance to the cylindrical portion (43), and
so-called oil churning loss increases. This leads to an increase in
motive energy of the electric motor (50). Further, if the oil in
the central recess (26) is agitated by the cylindrical portion
(43), the high-pressure gas refrigerant in the casing (15) may be
mixed with the oil, or the oil may turn into a fine mist. As a
result, after all, it becomes difficult for the oil agitated in the
central recess (26) to go back to the oil reservoir (18) due to its
own weight. This causes a shortage of oil in the oil reservoir
(18). The present embodiment therefore provides the annular groove
(78) on the bottom (26a) of the central recess (26) to prevent the
oil in the central recess (26) from being agitated by the
cylindrical portion (43).
[0075] More particularly, the refrigerant which has been used to
lubricate the bearing metal (44) and flowed into the central recess
(26) falls down into the annular groove (78) from the bottom (26a)
of the central recess (26). When the oil level in the annular
groove (78) exceeds the level of the inlet port (90a) of the first
oil supply hole (91), the oil in the annular groove (78) flows into
the first oil supply hole (91). This oil passes through the first
oil supply hole (91), and then flows upward through the second oil
supply hole (92). In the course of this flow, the high-pressure oil
is decompressed in the second oil supply hole (92) by the screw
member (93). The oil which has passed through the second oil supply
hole (92) flows into the oil groove (95) via the oil communication
passage (94) inside the fixed scroll (30). As a result, the sliding
portion of the compression mechanism (20) between the sliding
portion (35) of the fixed thrust surface and the sliding portion
(45) of the movable thrust surface is lubricated with the oil.
[0076] As described above, the oil which has flowed out into the
central recess (26) is appropriately supplied to the sliding
portion of the compression mechanism (20) through the annular
groove (78) and the oil supply channel (90). As a result, the rise
in the oil level in the central recess (26) is prevented, thereby
reducing the area of the cylindrical portion (43) of the movable
scroll (40) to be soaked iii the oil.
[0077] Further, if the oil level in the annular groove (78) rises
so much as to make the oil overflow from the annular groove (78)
into the central recess (26), this oil flows into the oil exhaust
channel (80), In the oil exhaust channel (80), the oil sequentially
flows through the horizontal hole (81), the vertical hole (82), and
the oil catch plate (83) to be guided into the core cut (51a). The
oil in the core cut (51a) further flows down along the inner
peripheral surface of the casing (15), and is delivered to the oil
reservoir (18) in the end.
[0078] In this manner, the oil which has overflowed from the
annular groove (78) returns directly to the oil reservoir (18)
through the oil exhaust channel (80). Thus, the rise in the oil
level in the central recess (26) is prevented, thereby reducing the
area of the cylindrical portion (43) of the movable scroll (40) to
be soaked in the oil.
Advantages of Embodiment
[0079] In the embodiment described above, the annular groove (78)
is provided on the bottom (26a) of the central recess (26) of the
housing (25), which allows the annular groove (78) to catch the oil
used to lubricate the bearing metal (44). This reduces the
possibility of the cylindrical portion (43) of the movable scroll
(40) being soaked in the oil in the central recess (26), thereby
reducing the oil churning loss at the cylindrical portion (43)
during its rotation. As a result, the motive energy of the electric
motor (50) is reduced, which contributes to energy saving more
effectively.
[0080] In addition, since this structure prevents the cylindrical
portion (43) from agitating the oil in this manner, it also
prevents a compressed fluid from being mixed with the oil, and
further prevents the oil from turning into a mist. Thus, the oil
used to lubricate the bearing metal (44) can immediately return to
the oil reservoir (18), and therefore so-called oil shortage is
eliminated.
[0081] Furthermore, in the embodiment described above, the annular
groove (78) is provided around the bearing metal (28) of the main
journal (64), which allows for providing the cylindrical projection
(79) between the annular groove (78) and the bearing metal (28).
This structure allows the cylindrical projection (79) to be
elastically deformed along the main journal (64) even if the main
journal (64) inclines with respect to the axial center. Thus, the
main journal (64) is prevented from partially contacting with the
bearing metal (28), thereby reducing bearing load on the main
journal (64). The annular groove (78) functions not only as a
groove which catches and delivers the oil to the oil supply channel
(90) but also as a so-called elastic groove. This allows for
simplifying the structure of the housing (25).
[0082] On top of that, according to the embodiment described above,
part of the oil which has flowed out into the central recess (26)
returns directly to the oil reservoir (18) through the oil exhaust
channel (80). This prevents the cylindrical portion (43) from being
soaked in the oil. In particular, according to the present
embodiment, the inlet port (80a) of the oil exhaust channel (80) is
arranged to be level with the bottom (26a) of the central recess
(26). Thus, even when the oil overflows from the annular groove
(78), this oil can be immediately introduced to the oil exhaust
channel (80).
[0083] Furthermore, according to the embodiment described above,
the inlet port (90a) of the oil supply channel (90) is opened to
the inside of the annular groove (78), and the inlet port (80a) of
the oil exhaust channel (80) is opened to the inside of the central
recess (26). That is, the inlet port (90a) of the oil supply
channel (90) is located at a lower level than the inlet port (80a)
of the oil exhaust channel (80). Thus, the oil which has flowed out
into the central recess (26) is introduced to the oil supply
channel (90) earlier than to the oil exhaust channel (80). This
allows for supplying the oil to the sliding portions (35, 45) of
the compression mechanism (20) successfully, and increases
reliability of the scroll compressor (10).
First Variation of Embodiment
[0084] The scroll compressor (10) according to a first variation
illustrated in FIG. 5 is different from the above embodiment in e
configuration of the oil exhaust channel (80). Specifically, the
inlet port (80a) of the oil exhaust channel (80) of the first
variation is opened to the inside of the annular groove (78). More
particularly, the oil exhaust channel (80) has a horizontal hole
(81) which extends radially outward from inside the annular groove
(78), and a vertical hole which extends downward from the radially
outer end of the horizontal hole (81). In the annular groove (78),
the inlet port (90a) of the oil supply channel (90) is located at a
lower level than the inlet port (80a) of the oil exhaust channel
(80).
[0085] In the first variation, the oil is introduced to the oil
supply channel (90) preferentially if the oil level in the annular
groove (78) is located at a level between the inlet port (90a) of
the oil supply channel (90) and the inlet port. (80a) of the oil
exhaust channel (80). However, when the oil level in the annular
groove (78) reaches the level of the inlet port (80a) of the oil
exhaust channel (80), the oil is introduced to both of the oil
supply channel (90) and the oil exhaust channel (80). Thus, in the
first variation, too, the oil which has flowed out into the central
recess (26) is introduced to the oil supply channel (90) earlier
than to the oil exhaust channel (80). This allows the oil to be
supplied to the sliding portions (35, 45) of the compression
mechanism (20) successfully, and increases the reliability of the
scroll compressor (10).
[0086] Further, in the first variation, the oil in the annular
groove (78) is prevented from overflowing into the central recess
(26), since the oil in the annular groove (78) is delivered to both
of the oil supply channel (90) and the oil exhaust channel (80). As
a result, the cylindrical portion (43) of the movable scroll (40)
is more reliably prevented from being soaked in the oil.
[0087] The other functions and effects of the first variation are
the same as those of the embodiment described above.
Second Variation of Embodiment
[0088] The second variation illustrated in FIGS. 6 and 7 includes a
housing which has a similar configuration to the counterpart of the
first variation but which includes a partition member (100) in the
annular groove (78). The partition member (100) extends from a
lower bottom of the annular groove (78) to an upper open end of the
annular groove (78) in the axial direction of the annular groove
(78). The partition member (100) has an approximately U-shaped
cross-section on a plane perpendicular to the axial direction of
the annular groove (78), and is fitted in the annular groove
(78).
[0089] The partition member (100) has an arc-shaped vertical wall
(100a) which is curved along the inner peripheral surface of the
annular groove (78), and a pair of side-walls (100b) which are
located at both ends of the vertical wall (100a) in its
circumferential direction. The vertical wall (100a) is arranged to
face the inlet port (80a) of the oil exhaust channel (80).
[0090] Each of the sidewalls (100b) extends in a radial direction
from the inner peripheral surface to the outer peripheral surface
of the annular groove (78). This partition member (100) partitions
the inside of the annular groove (78) into a first space (S1)
outside the partition member (100), and a second space inside the
partition member (100). The inlet port (90a) of the oil supply
channel (90) communicates with the first space (S1). The inlet port
(80a) of the oil exhaust channel (80) communicates with the second
space (S2),
[0091] In the second variation, the opening area of the upper end
of the first space (S1) is larger than the opening area of the
upper end of the second space (S2). That is, the volume of the
first space (S1) is larger than the volume of the second space (S2)
inside the annular groove (78). Thus, in the second variation, the
oil which has flowed out into the central recess (26) flows down
more into the first space (S1) than into the second space (S2),
thus making it possible to store a sufficient amount of oil in the
first space (S1). This allows the oil to be supplied to the sliding
portions (35, 45) of the compression mechanism (20) via the first
space (S1) and the oil supply channel (90) successfully, and
increases the reliability of the scroll compressor (10).
[0092] The other functions and effects of the second variation are
the same as those of the above embodiment,
Other Embodiments
[0093] The embodiment described above may be modified to have the
following configurations.
[0094] In the above embodiment, the bottom (26a) of the central
recess (26) is provided with an annular recess (78) which surrounds
the main journal (64). However, this recess (78) does not
necessarily have an annular shape, but may have a rectangular,
linear, or dotted cross-section on a plane perpendicular to the
axial direction. That is, the recess (78) may have any shape as
long as it is capable of catching the oil flowing out into the
central recess (26).
INDUSTRIAL APPLICABILITY
[0095] As can be seen from the foregoing description, the present
invention relates to a scroll compressor, and is particularly
useful for providing an effective measure to supply oil to a
sliding portion of a compression mechanism.
DESCRIPTION OF REFERENCE CHARACTERS
[0096] 10 scroll compressor [0097] 15 casing [0098] 18 oil
reservoir [0099] 20 compression mechanism [0100] 25 housing [0101]
26 central recess (receiving portion) [0102] 26a bottom [0103] 28
bearing metal (bearing) [0104] 30 fixed scroll [0105] 35 sliding
portion of fixed thrust surface [0106] 40 movable scroll [0107] 43
cylindrical portion (engaging portion) [0108] 44 bearing metal
(sliding portion) [0109] 45 sliding portion of movable thrust
surface [0110] 50 electric motor [0111] 60 drive shaft [0112] 70
oil supply passage [0113] 75 oil supply pump (oil transfer
mechanism) [0114] 78 annular groove (recess) [0115] 80 oil exhaust
channel [0116] 80a inlet port (on the oil exhaust channel side)
[0117] 90 oil supply channel [0118] 90a inlet port (on the oil
supply channel side) [0119] 100 partition member [0120] S1 first
space [0121] S2 second space
* * * * *