U.S. patent application number 11/911656 was filed with the patent office on 2009-03-05 for scroll fluid machine.
Invention is credited to Yuji Takei.
Application Number | 20090060768 11/911656 |
Document ID | / |
Family ID | 37114989 |
Filed Date | 2009-03-05 |
United States Patent
Application |
20090060768 |
Kind Code |
A1 |
Takei; Yuji |
March 5, 2009 |
Scroll Fluid Machine
Abstract
A scroll fluid machine having a scroll unit that includes a
fixed scroll (36) and a movable scroll (38) that are each
constructed from an end plate and a scroll wall integral with the
end plate, and also includes a chip seal (42) provided at the tip
of the scroll wall of one of the scrolls and in relative sliding
contact with the end plate of the other scroll. For example, a part
(radial projection) of a chip seal (42) on the movable scroll side
is projected from an outer wall surface of a scroll wall (38b), and
when a pressure chamber is formed between the fixed scroll and the
movable scroll, the radial projection is in relative sliding
contact with the inner wall surface of a scroll wall (36b) of the
fixed scroll to secure a fine gap (G) between the inner and outer
wall surfaces. The simple structure as above can relax conditions
of sliding between the scroll walls with sealability of the
pressure chamber maintained, and the scroll fluid machine has
excellent durability.
Inventors: |
Takei; Yuji; (Gunma,
JP) |
Correspondence
Address: |
BAKER BOTTS LLP;C/O INTELLECTUAL PROPERTY DEPARTMENT
THE WARNER, SUITE 1300, 1299 PENNSYLVANIA AVE, NW
WASHINGTON
DC
20004-2400
US
|
Family ID: |
37114989 |
Appl. No.: |
11/911656 |
Filed: |
April 5, 2006 |
PCT Filed: |
April 5, 2006 |
PCT NO: |
PCT/JP2006/307201 |
371 Date: |
October 15, 2007 |
Current U.S.
Class: |
418/55.4 |
Current CPC
Class: |
F01C 1/0215 20130101;
F04C 18/0215 20130101; F04C 23/003 20130101; F04C 27/005 20130101;
F04C 27/001 20130101; F01C 11/004 20130101 |
Class at
Publication: |
418/55.4 |
International
Class: |
F01C 19/00 20060101
F01C019/00; F01C 1/04 20060101 F01C001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 14, 2005 |
JP |
2005-116985 |
Claims
1. A scroll fluid machine having a scroll unit that comprises a
fixed scroll and a movable scroll each constructed from an end
plate and a scroll wall integral with said end plate, and comprises
a chip seal provided at a tip of a scroll wall of one of said
scrolls and in relative sliding contact with an end plate of the
other scroll, characterized in that said scroll unit further
comprises a radial projection provided on a first wall surface as
one of wall surfaces of said scroll walls facing each other and
being in relative sliding contact with a second wall surface as the
other wall surface to secure a fine gap between said wall surfaces
when a pressure chamber is formed between said fixed scroll and
said movable scroll.
2. The scroll fluid machine according to claim 1, wherein said
radial projection is formed integrally with said chip seal.
3. The scroll fluid machine according to claim 2, wherein said chip
seal includes a top seal surface which is in relative sliding
contact with said end plate of said the other scroll, and a sliding
contact surface which is connected perpendicularly to a side edge
of said top seal surface and which is positioned relatively to said
first wall surface with a distance corresponding to said fine
gap.
4. The scroll fluid machine according to claim 2, wherein said
scroll unit further comprises a holding means for holding said chip
seal at said tip of said scroll wall.
5. The scroll fluid machine according to claim 4, wherein said
holding means comprises a recessed portion and a projected portion
which are provided on said chip seal and said scroll wall and which
are engaged with each other.
6. The scroll fluid machine according to claim 4, wherein said
holding means comprises an adhesive layer.
7. The scroll fluid machine according to claim 1, wherein said chip
seal is made of one material selected from the group consisting of
a polyphenylenesulfide group resin, a polyetheretherketone group
resin and a polyimide group resin.
8. The scroll fluid machine according to claim 1, wherein a motor
is further provided, and said scroll unit is provided on each end
of a rotational shaft of said motor.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to a scroll fluid machine, and
specifically, to a scroll fluid machine improved in durability of
scroll unit.
BACKGROUND ART OF THE INVENTION
[0002] For example, a scroll fluid machine used as a fluid machine
in a refrigeration circuit of an air conditioning system for
vehicles has a scroll unit, and the scroll unit includes a fixed
scroll and a movable scroll. Each of these fixed scroll and movable
scroll has an end plate and a scroll wall integral with the end
plate, and the scrolls are disposed at a condition where both
scroll walls are engaged with each other so that therebetween a
gas-tight pressure chamber (fluid pocket) is formed via a chip seal
on the tip of the scroll wall. The movable scroll is operated at an
orbital movement relative to the fixed scroll by receiving a drive
force via an orbital unit, and by the change of the displacement
and the position of the above-described pressure chamber
accompanied with this orbital movement, the fluid (fro example,
refrigerant) in the pressure chamber is compressed or expanded (for
example, Patent document 1).
[0003] Patent document 1: JP-A-8-261171
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0004] In the conventional scroll fluid machine as described above,
because the scroll walls of the fixed scroll and the movable scroll
locally slide relatively to each other to form a pressure chamber,
if the sliding contact condition between the scroll walls can be
relaxed, the lives of these fixed scroll and movable scroll,
ultimately, the life of the fluid machine, may be extended.
[0005] Where, in order to relax the sliding contact condition
between the scroll walls, for example, a fine gap may be secured
between both scroll walls within a range which does not decrease
the sealability of the pressure chamber, and the scroll walls may
be in non-sliding contact with each other. In order to secure a
fine gap, however, the processing accuracy and the assembly
accuracy of not only the fixed scroll and the movable scroll but
also the orbital unit have to be increased.
[0006] Further, because a great centrifugal force acts on the
movable scroll as its orbital speed becomes faster, if a fine gap
is secured, the orbital posture of the movable scroll in a high
speed range becomes unstable, and depending upon the posture, there
may be a fear that a galling occurs between the scroll walls.
Therefore, when a fine gap is secured, it is necessary to increase
the rigidity of the orbital unit or to employ a design change such
as addition of parts to the orbital unit, so as to stabilize the
orbital posture of the movable scroll.
[0007] Thus, if a fine gap is tried to be provided between the
scroll walls, it becomes necessary to increase the processing
accuracy or the assembly accuracy of the scroll unit or the orbital
unit, to increase the rigidity of the orbital unit, or to change
the design such as addition of parts to the orbital unit, and
therefore, reduction in productivity or cost up of the fluid
machine may be caused.
[0008] Accordingly, an object of the present invention is to
provide a scroll fluid machine which can relax the sliding contact
condition between scroll walls by a simple structure while
maintaining a good sealability of a pressure chamber, thereby
having an excellent durability.
Means for Solving the Problems
[0009] To achieve the above object, a scroll fluid machine
according to the present invention has a scroll unit that comprises
a fixed scroll and a movable scroll each constructed from an end
plate and a scroll wall integral with the end plate, and comprises
a chip seal provided at a tip of a scroll wall of one of the
scrolls and in relative sliding contact with an end plate of the
other scroll, and is characterized in that the scroll unit further
comprises a radial projection provided on a first wall surface as
one of wall surfaces of the scroll walls facing each other and
being in relative sliding contact with a second wall surface as the
other wall surface to secure a fine gap between the wall surfaces
when a pressure chamber (fluid pocket) is formed between the fixed
scroll and the movable scroll.
[0010] In such a scroll fluid machine according to the present
invention, although the above-described radial projection may be
formed separately from the chip seal, it is preferred that the
radial projection is formed integrally with the chip seal. In this
case, it is preferred that the chip seal includes a top seal
surface which is in relative sliding contact with the end plate of
the other scroll, and a sliding contact surface which is connected
perpendicularly to a side edge of the top seal surface and which is
positioned relatively to the first wall surface with a distance
corresponding to the fine gap.
[0011] Further, the above-described scroll unit may further
comprise a holding means for holding the chip seal at the tip of
the scroll wall. This holding means may comprise a recessed portion
and a projected portion which are provided on the chip seal and the
scroll wall and which are engaged with each other. Furthermore, as
a preferable embodiment, the holding means may comprise an adhesive
layer.
[0012] Further, although the material for the chip seal is not
particularly limited, preferably it is made of one material
selected from the group consisting of a polyphenylenesulfide group
resin, a polyetheretherketone group resin and a polyimide group
resin.
[0013] Various forms can be employed as the scroll fluid machine
according to the present invention, and for example, it can be
formed as a compressor or an expander, and further, as a scroll
fluid machine having both functions of compression and expansion.
For example, it can be structured as a scroll fluid machine wherein
a motor is further provided, and the scroll unit is provided on
each end of a rotational shaft of the motor.
Effect According to the Invention
[0014] In the scroll fluid machine according to the present
invention, since the radial projection secures a fine gap between
the wall surfaces of both scroll walls, the sliding contact
condition between the scroll walls can be relaxed while the
sealability of the pressure chamber can be maintained, and abrasion
of the scroll walls can be suppressed. Further, in this fluid
machine, by the structure in which the radial projection secures a
fine gap between the wall surfaces of the scroll walls, even if the
movable scroll is operated at a high-speed orbital movement, the
orbital posture of the movable scroll is not disturbed, and
occurrence of a galling between the scroll walls can be prevented.
Consequently, the fluid machine according to the present invention
has an excellent durability.
[0015] Further, in the scroll fluid machine according to the
present invention, by the structure in which a fine gap is secured
between the scroll walls, it is not necessary to mix a lubricant
oil in the operational fluid, and the structure is preferable for
making the machine oil-free. Therefore, for example, in a
refrigeration circuit applied with this fluid machine, because it
is not necessary to mix a lubricant oil in the refrigerant, the
coefficient of performance of the refrigeration circuit is
improved. Moreover, because it is not necessary to mix a lubricant
oil in the operational fluid, this fluid machine can be applied to
various uses.
[0016] Further, in the scroll fluid machine according to the
present invention, if the radial projection is formed integrally
with the chip seal, because the number of parts does not increase,
reduction in productivity and cost up can be prevented. Further, by
the structure in which the radial projection is formed integrally
with the chip seal, because a fine gap can be easily secured even
at a position which is most apart from an end portion of a drive
shaft supporting the movable scroll, even when the movable scroll
is operated at a high-speed orbital movement, disturbance of the
orbital posture of the movable scroll can be surely prevented.
[0017] Further, in a case where the chip seal has a top seal
surface and a sliding contact surface for securing a fine gap,
while an excellent durability can be given to each of the top seal
surface and the sliding contact surface, both surfaces can well
exhibit respective target functions. Further, in this case, because
the chip seal has the top seal surface projecting from the tip of
the scroll wall, during the operation, the surface contact pressure
between the chip seal and the end plate may be reduced
appropriately, and the durability of the chip seal may be
increased.
[0018] Further, in a case where a holding means for holding the
chip seal at the tip of the scroll wall is further provided, it
becomes possible to easily hold the radial projection on the scroll
wall side by this holding means. Further, by the structure in which
the holding means includes a recessed portion and a projected
portion which are provided on the chip seal and the scroll wall and
which are engaged with each other, the radial projection can be
held on the scroll wall side more easily and more securely.
Furthermore, by the structure in which the holding means includes
an adhesive layer, the radial projection can be held on the scroll
wall side further easily and further securely.
[0019] Further, in a case where the chip seal is made of one
material selected from the group consisting of a
polyphenylenesulfide group resin (PPS group resin), a
polyetheretherketone group resin (PEEK group resin) and a polyimide
group resin (PI group resin) which are excellent in abrasion
resistance, the durability of the scroll fluid machine can be
further increased.
[0020] Furthermore, in a case where the scroll fluid machine
according to the present invention is formed as a structure wherein
a motor is further provided, and the scroll unit is provided on
each end of a rotational shaft of this motor (namely, a structure
having two pressure chambers), it is possible to use one pressure
chamber as a chamber for compression and use the other pressure
chamber as a chamber for expansion. In such a structure, since the
expansion energy of an operational fluid in the expansion chamber
can be used as an auxiliary power for compressing an operational
fluid in the compression chamber, the consumption power may be
saved.
BRIEF EXPLANATION OF DRAWINGS
[0021] FIG. 1 is a vertical sectional view of a scroll fluid
machine applied to a refrigeration circuit according to an
embodiment of the present invention.
[0022] FIG. 2 is a back surface view of a chip seal applied to the
fluid machine depicted in FIG. 1.
[0023] FIG. 3 is an elevational view of a movable scroll applied to
the fluid machine depicted in FIG. 1.
[0024] FIG. 4 is a plan view showing the movable scroll depicted in
FIG. 3 together with the chip seal depicted in FIG. 2.
[0025] FIG. 5 is an enlarged, partial sectional view as viewed
along V-V line of FIG. 4.
[0026] FIG. 6 is an explanation diagram showing the sliding contact
position between scroll walls of a fixed scroll and a movable
scroll and a chip seal in the fluid machine depicted in FIG. 1.
[0027] FIG. 7 is an elevational view of a movable scroll according
to a modification of the present invention.
[0028] FIG. 8 is a sectional view showing a part of a scroll wall
together with a chip seal according to a modification of the
present invention.
[0029] FIG. 9 is a sectional view showing a part of a scroll wall
together with a chip seal and a radial projection according to
another modification of the present invention.
EXPLANATION OF SYMBOLS
[0030] 1: scroll fluid machine [0031] 35: scroll unit [0032] 36:
fixed scroll [0033] 38: movable scroll [0034] 36a, 38a: end plate
[0035] 36b, 38b: scroll wall [0036] 40: pressure chamber [0037] 42:
chip seal [0038] 42b: seal surface (top seal surface) [0039] 42c:
outer side surface (sliding contact surface) [0040] G: fine gap
THE BEST MODE FOR CARRYING OUT THE INVENTION
[0041] Hereinafter, desirable embodiments of the present invention
will be explained referring to figures.
[0042] FIG. 1 depicts a scroll fluid machine 1 according to an
embodiment of the present invention, which is applied, for example,
to a refrigeration circuit of an air conditioning system for
vehicles. The refrigeration circuit has a circulation passageway 2,
and refrigerant as the operational fluid is circulated in the
circulation passageway 2. Where, a lubricant oil is not mixed in
the refrigerant, and this refrigeration circuit is oil free. In
this embodiment, fluid machine 1 has both functions of a compressor
and an expander, and the fluid machine disposed in circulation
passageway 2 divides the circulation passageway 2 into a
high-pressure region 2a and a low-pressure region 2b. In
high-pressure region 2a, a condenser 4 and a receiver 6 are
disposed in order in the circulation direction of refrigerant, and
in low-pressure region 2b, an evaporator 8 is interposed.
[0043] Fluid machine 1 has a motor housing 10, and the motor
housing 10 has a motor casing 12 with a cup-like shape and an end
plate 14 fixed to the opening end of the motor casing 12. A
cylindrical stator 16 is fitted into a circumferential wall 12a of
casing 12, and stator 16 surrounds a columnar rotor 18 free to
rotate. A drive shaft 20 extends through the center of rotor 18,
and the rotor 18 rotates integrally with drive shaft 20. Shaft
holes are provided on the central parts of end wall 12b of casing
12 and end plate 14, respectively, and both end portions of drive
shaft 20 are projected from these shaft holes. Drive shaft 20 is
supported free to rotate by end wall 12b and end plate 14 via ball
bearings 22 provided in the shaft holes. Further, in the shaft
holes, lip seals 24 are provided at positions outside ball bearings
22, and the shaft holes are closed by the lip seals 24.
[0044] A power supply port 26 is provided to circumferential wall
12a of motor casing 12, and power can be supplied to stator 16 from
an external power source (not shown) through power supply port 26.
When power is supplied to stator 16, rotor is rotated by the
electromagnetic force of stator 16, thereby rotating drive shaft
20.
[0045] A compression housing is provided to each end of the
above-described motor housing 10, and the compression housing has a
cup-like compression casing 30. Compression casing 30 is fixed to
motor housing 10 by a plurality of bolts 32, and the opening end of
compression casing 30 is fitted at a gas-tight condition to each
end of motor housing 10 via O-ring 34.
[0046] A scroll unit 35 is provided in compression casing 30, and
scroll unit 35 has metal fixed scroll 36 and movable scroll 38.
These fixed scroll 36 and movable scroll 38 have end plates 36a,
38a and scroll walls 36b, 38b integral with end plates 36a, 38a,
and in this fluid machine 1, the end wall of compression casing 30
is formed also as end plate 36a of fixed scroll 36.
[0047] These fixed scroll 36 and movable scroll 38 are disposed so
as to be engaged with each other in order to form pressure chamber
40 (fluid pocket) therebetween. Under this disposition, movable
scroll 38 can be operated at an orbital movement relative to fixed
scroll 36, and accompanied with this orbital movement, pressure
chamber 40 is changed in its displacement as well as in its
position.
[0048] Resin chip seals 42 are provided on the tips of scroll walls
36b, 38b, respectively, and scroll walls 36b, 38b of fixed scroll
36 and movable scroll 38 are in sliding contact with end plates
36a, 38a of scrolls 36, 38 positioned at the respective counter
sides, via chip seals 42.
[0049] Hereinafter, chip seal 42 will be explained, and because the
structures of chip seals 42 provided on fixed scroll 36 and movable
scroll 38, and fixing means of chip seals 42 to scroll walls 36b,
38b, are same as each other, the explanation will be carried out by
exemplifying chip seal 42 of movable scroll 38 side.
[0050] As shown in FIG. 2, chip seal 42 extends spirally, and has
constant width and thickness. From the back surface among both flat
surfaces parallel to each other which define the thickness of chip
seal 42, pins 42a are projected at predetermined positions in the
lengthwise direction (spiral direction).
[0051] As shown in FIG. 3, on the tip of scroll wall 38b to be
attached with chip seal 42, the region connected to the outer wall
surface among both wall surfaces of scroll wall 38b is formed as a
flat surface 46 at a position close to end plate 38a as compared
with tip surface 44 connected to the inner wall surface. Flat
surface 46 also extends spirally, and pin holes 46a are formed at
predetermined positions in the lengthwise direction.
[0052] As shown in FIG. 4, chip seal 42 is overlapped with flat
surface 46, and at that time, pins 42a are inserted into pin holes
46a. Therefore, as shown in FIG. 4, by the fitting of pins 42a into
pin holes 46a, chip seal 42 is fixed to the tip of scroll wall
38b.
[0053] Where, as shown in FIG. 5, a part of chip seal 42 is
projected at a predetermined length from tip surface 44 of scroll
wall 38b in the thickness direction of chip seal 42, and the front
surface of chip seal 42 is parallel to the tip surface 44 of scroll
wall 38b, but is positioned near end plate 36a of fixed scroll 36
as compared with the tip surface 44. Therefore, the front surface
of chip seal 42 forms a seal surface 42b which is in sliding
contact with end plate 36a of fixed scroll 36, over its entire
region.
[0054] Further, a part of chip seal 42 is projected at a
predetermined length from the outer wall surface of scroll wall 38b
in the width direction of chip seal 42 (the radial direction of
scroll wall 38b), and outer side surface 42c among both side
surfaces defining the width of chip seal 42 is parallel to the
outer wall surface of scroll wall 38b, but is positioned near the
inner wall surface of scroll wall 36b of fixed scroll 36 as
compared with this outer wall surface. Therefore, at the position
in the lengthwise direction where scroll walls 36b, 38b are closest
to each other, outer side surface 42c of chip seal 42 is in sliding
contact with the inner wall surface of scroll wall 36b of fixed
scroll 36. At this position in the lengthwise direction, a fine gap
G is formed between the inner and outer wall surfaces of scroll
walls 36b, 38b via chip seal 42.
[0055] In more detail, FIG. 6 is a modification diagram for
explaining the sliding contact positions between scroll walls 36b,
38b and outer side surface 42c of chip seal 42, and outer side
surface 42c of chip seal 42 at movable scroll 38 side is in sliding
contact with the inner wall surface of scroll wall 36b of fixed
scroll 36 at two positions (points A, B). On the other hand, outer
side surface 42c of chip seal 42 at fixed scroll 36 side is in
sliding contact with the inner wall surface of scroll wall 38b of
movable scroll 38 at two positions (points C, D).
[0056] Fine gap G is formed between the inner and outer wall
surfaces of scroll walls 36b, 38b at each of these points A, B, C,
D in the lengthwise direction, and each of points A, B, C, D is
positioned at each end of each pressure chamber 40 in the
lengthwise direction of scroll walls 36b, 38b. Where, outer side
surface 42c of each chip seal 42 is in sliding contact with the
inner wall surface at a position near the root of each of scroll
walls 36b, 38b. Further, in FIGS. 4 and 6, in order to indicate
chip seal 42 clearly, the hatching is provided only to chip seal
42.
[0057] Referring to FIG. 1 again, movable scroll 38 is connected to
each end of drive shaft 20 via an orbital unit to enable the
orbital movement of movable scroll 38. In more detail, an eccentric
bush 50 is fixed to each end of drive shaft 20, and the eccentric
bush 50 can be rotated integrally with drive shaft 20. Eccentric
bush 50 is surrounded by a boss provided integrally to the outer
surface of end plate 38a, and between the eccentric bush 50 and the
boss, ball bearing 52 is interposed.
[0058] Further, a rotation preventing mechanism for preventing the
rotation of movable scroll 38 around eccentric bush 50 is provided
between end plate 38a of each movable scroll 38 and end wall 12b or
end plate 14. The rotation preventing mechanism includes, for
example, a crank pin 54, and the crank pin 54 connects between end
wall 12b or end plate 14 and end plate 38a via two ball bearings
56.
[0059] Where, counter weights 58 are attached to drive shaft 20 at
positions of both sides of rotor 18, and the counter weights 58
become balance weights for the orbital movements of movable scrolls
38. High-pressure ports 60 and low-pressure ports (not shown) are
provided on compression casing 30 for supplying and discharging
high-pressure and low-pressure refrigerants to and from both scroll
units 35. In more detail, each high-pressure port 60 provided
through the end wall of compression casing 30, namely, the central
part of end plate 36a of fixed scroll 36, and pressure chamber 40
positioned at the central part of end plate 36a is connected to
high-pressure region 2a of circulation passageway 2 via the
high-pressure port 60. The low-pressure port is provided through
the circumferential wall of compression casing 30, and the inside
of compression casing 30 is connected to low-pressure region 2b of
circulation passageway 2 via the low-pressure port.
[0060] Hereinafter, the operation of scroll fluid machine 1 in the
above-described refrigeration circuit will be explained.
[0061] When rotor 18, that is, drive shaft 20, is rotated by the
power supply to stator 16, accompanied with the rotation of drive
shaft 20, movable scroll 38 is served to an orbital movement via
eccentric bush 50. By this orbital movement, scroll unit 35 on the
left side in FIG. 1 carries out the following compression
process.
[0062] First, the left-side scroll unit 35 sucks low-pressure gas
refrigerant from low-pressure region 2b of circulation passageway 2
into pressure chamber 40 positioned at the outer circumferential
region through the low-pressure port and the space between scroll
unit 35 and compression casing 30. Thereafter, the pressure chamber
40 having sucked the refrigerant moves toward the central portions
of end plates 36a, 38a along scroll walls 36b, 38b, and during this
movement, the refrigerant in the pressure chamber 40 is compressed
by reduction of the volume of the pressure chamber 40. Then, the
refrigerant compressed in the pressure chamber 40 flows out to
high-pressure region 2a of circulation passageway 2 through
high-pressure port 60 when the pressure chamber 40 is communicated
with the high-pressure port 60 at the central portions of end
plates 36a, 38a.
[0063] The high-pressure gas refrigerant flowed into high-pressure
region 2a is cooled and condensed at condenser 4, and after
becoming a high-pressure liquid refrigerant, bubbles and moisture
are removed at receiver 6. The high-pressure liquid refrigerant
having passed through receiver 6 is supplied to the right-side
scroll unit in FIG. 1, and this right-side scroll unit 35 carries
out the following expansion process.
[0064] In the right-side scroll unit 35, the high-pressure liquid
refrigerant sent from high-pressure region 2a of circulation
passageway 2 flows into pressure chamber 40 positioned at the
central portions of end plates 36a, 38a through high-pressure port
60. Thereafter, the pressure chamber 40, into which the refrigerant
has flowed, moves toward the outer circumferential portions of end
plates 36a, 38a along scroll walls 36b, 38b, and during this
movement, the refrigerant in the pressure chamber 40 is expanded by
increase of the volume of the pressure chamber 40.
[0065] The refrigerant expanded in pressure chamber 40 flows into
low-pressure region 2b of circulation passageway 2 through the
space between scroll unit 35 and compression casing 30 and the
low-pressure port at the outer circumferential region of scroll
unit 35 when the pressure chamber 40 communicates with the space.
The gas/liquid mixed low-pressure refrigerant flowed out to
low-pressure region 2b becomes low-pressure gas refrigerant, and
thereafter, the refrigerant is sucked again into pressure chamber
40 of left side scroll unit 35.
[0066] In the above-described scroll fluid machine 1, a part of
chip seal 42 (that is, a radial projection) is radially projected
from the outer wall surface of scroll wall 36b, 38b, and fine gap G
is secured between the inner and outer wall surfaces of scroll
walls 36b, 38b, thereby relaxing the sliding contact conditions
between scroll walls 36b, 38b. Consequently, the abrasion of scroll
walls 36b, 38b can be suppressed in this scroll fluid machine
1.
[0067] Further, in this scroll fluid machine 1, because a part of
chip seal 42 (radial projection) secures the fine gap G between the
inner and outer wall surfaces of scroll walls 36b, 38b, even in a
case where movable scroll 38 is in an orbital movement at a high
speed, the orbital posture of the movable scroll 38 is not be
disturbed. As a result, occurrence of galling between scroll walls
36b, 38b can be prevented.
[0068] Thus, since the abrasion of scroll walls 36b, 38b can be
suppressed and the occurrence of galling between scroll walls 36b,
38b can be prevented by a part of chip seal 42 (radial projection),
this scroll fluid machine 1 has an excellent durability. Besides,
in this scroll fluid machine 1, because the fine gap G is secured
between scroll walls 36b, 38b, even if lubricant oil is not mixed
in the refrigerant, seizure does not occur between scroll walls
36b, 38b. Therefore, in a refrigeration circuit applied with this
fluid machine 1, it is possible to make the refrigeration circuit
oil-free, and in such a case, because a lubricant oil is not mixed
in the refrigerant, the circuit has a good coefficient of
performance. Moreover, because it is not necessary to mix a
lubricant oil in the operational fluid, this fluid machine 1 can be
applied to various uses.
[0069] Further, in this refrigeration circuit, since scroll units
35 each functioning as a compressor or an expander are provided to
both ends of the drive shaft, it is possible to save the
consumption power. This is because the expansion of the refrigerant
in pressure chamber 40 of right-side scroll unit 35 gives an
auxiliary power to drive shaft 20 via the orbital movement of
movable scroll 38, and by utilizing this auxiliary power, the
refrigerant can be compressed in pressure chamber 40 of left-side
scroll unit 35.
[0070] Where, in this scroll fluid machine 1, it is possible to
maintain the sealability of pressure chamber 40 by making the fine
gap G several-tens .mu.m or less.
[0071] The present invention is not limited to the above-described
embodiment, and various modifications can be employed.
[0072] For example, although, in the above-described embodiment,
pins 42a are formed on chip seal 42 and pin holes 46a are formed on
flat surface 46 as a holding means for holding chip seal 42 on
scroll walls 36b, 38b, the pin holes may be formed on chip seal 42
and the pins may be formed on flat surface 46. However, from the
viewpoint of the productivity of the fluid machine, it is preferred
that pins 42a are formed on chip seal 42 and pin holes 46a are
formed on flat surface 46.
[0073] Further, as the holding means, a projected strip may be
formed instead of pins 42a, and as shown in FIG. 7, a groove 46b
for fitting the projected strip thereinto may be formed instead of
pin holes 46a. Namely, the holding means may be provided between
scroll walls 36b, 38b and chip seal 42 and may include a recessed
portion and a projected portion being engaged with each other, and
by such a holding means, chip seal 42 can be held by scroll walls
36b, 38b easily and securely.
[0074] Moreover, the holding means may include an adhesive layer 70
as shown in FIG. 8, or the holding means may be formed only by
adhesive layer 70. Further, although a part of chip seal 42 is
projected from the outer wall surface of scroll wall 36b or 38b in
the aforementioned embodiment, a part of chip seal 42 may be
projected from the inner wall surface of scroll wall 36b or
38b.
[0075] Further, as shown in FIG. 8, a chip seal 72 having a portion
projected from the outer and inner wall surfaces of scroll wall 36b
or 38b may be employed. In this case, when pressure chamber 40 is
formed, outer wall surface 72c and inner wall surface 72d of chip
seal 72 is in sliding contact with the inner wall surface and outer
wall surface of counter-side scroll wall 36b or 38b, and a fine gap
G is secured at each sliding contact portion. Therefore, in this
case, although chip seal 72 may be provided on both of fixed and
movable scrolls 36, 38, chip seal 72 may be provided on one of
fixed scroll 36 and movable scroll 38, and a conventional chip seal
may be provided on the other scroll.
[0076] Further, as shown in FIG. 9, a radial projection 76 may be
provided as a member separate from a conventional chip seal 74. In
this case, by radial projection 76, a fine gap G can be secured
between the inner and outer wall surfaces of scroll walls 36b, 38b.
However, in a case where chip seal 74 and radial projection 76 are
formed separately from each other, because the number of parts
increases and it is necessary to provide means for holding chip
seal 74 and radial projection 76 on scroll walls 36b, 38b,
respectively, thereby causing a reduction of productivity and an
increase of cost of the fluid machine, a structure is preferred
wherein a part of chip seal 42 is projected from the outer wall
surface as in the aforementioned embodiment. In other words, it is
preferred that radial projection 76 is formed integrally with chip
seal 74.
[0077] Further, if a part of chip seal 42 is projected from the
outer wall surface of scroll wall 36b or 38b as in the
aforementioned embodiment, because a fine gap G between scroll
walls 36b, 38b is defined at a position most apart from the end of
drive shaft 20 supporting movable scroll 38, even if the movable
scroll 38 is operated at a high-speed orbital movement, the
disturbance of the orbital posture of the movable scroll 38 can be
prevented securely.
[0078] Furthermore, if a part of chip seal 42 is projected from the
outer wall surface of scroll wall 36b or 38b as in the
aforementioned embodiment, because a seal surface 42b can be formed
also on the projected portion, during the operation of the fluid
machine, the surface pressure between chip seal 42 and end plates
36a, 38a can be reduced, and the durability of chip seal 42 can be
increased. Therefore, as chip seal 42, it is preferred that seal
surface 42b extends up to the projected portion in the width
direction and an outer side surface 42c is connected
perpendicularly to the side edge of the seal surface 42b.
[0079] In fluid machine 1 according to the aforementioned
embodiment, it is preferred that chip seal 42 is made of one
material selected from the group consisting of a
polyphenylenesulfide group resin (PPS group resin), a
polyetheretherketone group resin (PEEK group resin) and a polyimide
group resin (PI group resin), because these resins are excellent in
abrasion resistance, thereby further improving the durability of
the fluid machine.
[0080] Although fluid machine 1 according to the aforementioned
embodiment has two scroll units 35 provided on both end portions of
drive shaft 20, the scroll fluid machine according to the present
invention may have at least one scroll unit.
INDUSTRIAL APPLICATIONS OF THE INVENTION
[0081] The scroll fluid machine according to the present invention
can be applied to any fluid machine having a scroll unit, and in
particular, it is suitable as a fluid machine used for a
refrigeration circuit in an air conditioning system for
vehicles.
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