U.S. patent application number 09/983017 was filed with the patent office on 2002-05-16 for scroll fluid machine.
Invention is credited to Kimura, Hideyuki, Unami, Atsushi.
Application Number | 20020057976 09/983017 |
Document ID | / |
Family ID | 18799978 |
Filed Date | 2002-05-16 |
United States Patent
Application |
20020057976 |
Kind Code |
A1 |
Kimura, Hideyuki ; et
al. |
May 16, 2002 |
Scroll fluid machine
Abstract
To offer the seal configuration which prevents the leakage of
high pressure compressed fluid from the succeeding stage
compression section to the preceding stage compression section of a
multistage compression type fluid machine, a seal element 25 is
located on the rand 9a between the discharge port 2e located at the
end of the spiral lap groove of the preceding stage compression
section and the suction port 2f located at the start of the spiral
lap groove of the succeeding stage compression section to suck in
the compressed fluid discharged from said discharge port and cooled
through passing a cooler.
Inventors: |
Kimura, Hideyuki;
(Kanagawa-ken, JP) ; Unami, Atsushi;
(Kanagawa-ken, JP) |
Correspondence
Address: |
CROWELL & MORING LLP
INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Family ID: |
18799978 |
Appl. No.: |
09/983017 |
Filed: |
October 22, 2001 |
Current U.S.
Class: |
418/55.2 ; 418/5;
418/55.4 |
Current CPC
Class: |
F04C 18/0284 20130101;
F04C 29/04 20130101; F04C 18/0261 20130101; F04C 18/0269 20130101;
F04C 27/005 20130101; F04C 23/001 20130101 |
Class at
Publication: |
418/55.2 ;
418/55.4; 418/5 |
International
Class: |
F01C 011/00; F01C
001/04; F01C 019/08 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 20, 2000 |
JP |
2000-322025 |
Claims
What is claimed:
1. A scroll fluid machine with multi-stage compression section in
which the fluid compressed in the preceding stage compression
section is further compressed in the succeeding stage compression
section characterized in that: a lap groove is formed spiraling
from the vicinity of the discharge port of the compressed fluid of
the final stage compression space to the fluid take-in side of the
initial stage compression space, in the tip of the lap being formed
a tip seal grove to receive a seal element, and a rand is formed
between the discharge port at the compression end part of said
preceding stage compression section and the suction port of the
succeeding stage compression section; and an intermediate seal
element is received in the intermediate groove formed on the
surface of said rand which faces the end plate of the mating scroll
for preventing the leakage of the compressed fluid from said
succeeding stage compression section to said discharge port opening
side of said preceding stage compression section.
2. A scroll fluid machine with multi-stage compression section
according to claim 1 characterized in that said seal element
consists of; a tip seal received in the groove formed in the tip of
the spiral lap of both side forming said lap groove, and an
intermediate seal element located between said discharge port
opening and said suction port opening.
3. A scroll fluid machine with multi-stage compression section
according to claim 2 characterized in that, said intermediate seal
element is a circular seal element partitioning said succeeding
stage compression section circularly.
4. A scroll fluid machine with multi-stage compression section
according to claim 1 characterized in that said seal element
consists of; a first seal element which extends spirally from the
fluid take-in side of said preceding stage compression section side
to the final discharge port side of said succeeding stage
compression section and partitions said discharge port opening and
said suction port opening at said rand surface in the course of its
extension, and a second seal element, an end of which contacts the
side face of said first seal element at the side opposite to said
discharge port opening in the vicinity of said discharge port
opening and which extends from the vicinity of said discharge port
opening to the vicinity of said discharge port opening, surrounding
said succeeding stage compression section to contact the side face
of said first seal element at the side opposite to said suction
port opening.
5. A scroll fluid machine with multi-stage compression section
according to claim 1 characterized in that: a tip seal groove is
formed extending spirally from the fluid take-in side of said
initial stage compression section toward the compressed fluid
discharge port side of said final stage compression space, an
intermediate groove is formed communicating with said tip seal
groove in said rand between said discharge port opening and said
suction port opening, a set of seal elements consisting of a
plurality of seal elements is received in said intermediate groove
and said tip seal groove, said seal set consists of; a first tip
seal which extends from the compressed fluid discharge port side of
said final stage compression space toward said initial stage
compression space via said intermediate groove, a second tip seal
which extends parallel with said first tip seal from the compressed
fluid discharge port side of said final stage compression space to
the vicinity of said suction port opening where the second tip seal
depart from said first tip seal and contacts said first seal in the
vicinity of said discharge port opening, and a third tip seal which
extends in said tip groove parallel with said second tip seal from
the vicinity of said suction port opening to partition said
succeeding stage compression section circularly and further extends
parallel with said first tip seal toward said initial stage
compression section side.
6. A scroll fluid machine with multi-stage compression section
according to claim 1 characterized in that: a tip seal groove is
formed extending spirally from the fluid take-in side of said
initial stage compression section toward the compressed fluid
discharge port side of said final stage compression space, an
intermediate groove is formed communicating with said tip seal
groove in said rand between said discharge port opening and said
suction port opening, and said seal element is a single tip seal
received in said tip seal groove and said intermediate groove.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a scroll fluid machine for
compressing or expanding or pressure feeding fluid, specifically to
a seal configuration of a scroll fluid machine having multistage
compression section in which the fluid compressed in the preceding
stage compression section is cooled to be compressed in the
succeeding stage compression section and a seal element is provided
to prevent the leakage of the compressed fluid from the succeeding
stage compression section to the preceding stage compression
section.
[0003] 2. Description of the Related Art
[0004] It is general in scroll fluid machines that revolving
scrolls and stationary scrolls are cooled with cooling air or
cooling fluid to remove the heat generated by the compression of
the fluid. To attain a compression ratio larger than usual is
possible by increasing the number of turns of the scroll. However,
there arise problems by increasing the compression ratio than usual
that not only the machine becomes large but the life of the
bearings and seal elements are shortened due to the high
temperature higher than usual owing to the larger compression
ratio.
[0005] Therefore it becomes necessary to provide a larger cooling
device to obtain a larger amount of cold heat for removing the
increased heat due to increase compression ratio from the revolving
scroll and stationary scroll. In a scroll fluid machine, the fluid
is taken in from the peripheral part of the end plate of the
revolving scroll, the compression space into which the fluid is
taken in is reduced toward the center to compress the fluid, and
the compressed fluid is discharged from the discharge port located
in the center part. High level technique is necessary to
efficiently cool the center part.
[0006] For this reason, a multistage compression type scroll
machine was demanded which has two stages of compression sections,
the compressed fluid discharged from the preceding stage being
passed through the cooler to be introduced to the succeeding stage
to be again compressed. The multistage compression type scroll
machine can compress fluid to a desired high compression ratio
without raising the temperature of the constituent parts of the
scroll fluid machine higher than usual by restraining the
temperature of the compressed fluid in the preceding stage to the
temperature the constituent parts allow, cooling the compressed
fluid compressed in the preceding stage compression section, and
then again compressing the compressed and cooled fluid if the
succeeding stage compression section.
[0007] A multistage compression type scroll machine which has two
stages of compression sections and in which the compressed fluid
from the preceding stage is cooled by passing through a cooler and
then introduced to the succeeding stage to be again compressed is
disclosed in Japanese Unexamined Patent Publication 54-59608.
[0008] The conventional art includes, however, the problem as
described below. This will be explained with reference to FIGS. 10
to 12. The discharge port 2e in the vicinity of the final
compression chamber of the preceding stage compression section and
the suction port 2f, which communicate with the space into which
the fluid is taken in, of the succeeding stage compression section
are connected with a piping by the medium of a cooler not shown in
the drawing, the connection constituting an intermediate
passage.
[0009] Now, after the compression space S3 of the preceding stage
compression section communicates with the discharge port 2e of the
preceding stage compression section, the compression space S6 and
T6 of the succeeding stage compression section become communicated
with the compression space S5 of the preceding stage compression
section, as shown in FIG. 10. The fluid taken into the compression
space S6 is compressed by the rotation of the revolving scroll lap
10b to the compression space S8, and the fluid taken into the
compression space T6 is compressed to the compression space T8.
Therefore, the pressure in the space S8 is higher than that in the
space S6, and the pressure in the space T8 is higher than that in
the space T6.
[0010] As can be seen in FIG. 11(a), FIG. 11(b), and FIG. 12, which
show respectively A-A section, B-B section, and C-C section in FIG.
10, a tip seal 53 is received in the groove 41 formed in the tip of
the revolving scroll lap 10b and in the groove 40 formed in the tip
of the stationary scroll lap 9c respectively. As the tip seal 53 is
shaped narrower in width than that of the groove 40 and 41, the tip
seals 53, 53 receive the pressure of the compressed fluid of each
compression space to be pushed against the mirror face each mating
scroll and at the same time to be pushed against the wall each
groove toward lower pressure side.
[0011] Accordingly, the passage 30 and 31 communicating with the
compression space T6 are formed as shown in FIG. 11(a), and the
leakage to the lower pressure space T6 is possible.
[0012] The passage 32 and 51 communicating with the compression
space S8 are formed as shown in FIG. 11(b), and the leakage to the
lower pressure space S6 is possible.
[0013] The tip seal is pushed against the groove wall toward lower
pressure side. However, the side face of the tip seal and the
groove face can not be brought to absolute contact with each other
because of the imperfect flatness of the faces. Accordingly, the
leakage of high pressure fluid in the direction of arrow 76 to the
gap 80 between the tip seal 14 and 53 is possible as shown in FIG.
12(a) which shows C-C section in FIG. 10.
[0014] There is a gap between the bottom of the groove formed in
the tip of the revolving scroll lap and the tip seal 53, so the
leakage of the fluid is possible from higher pressure side to lower
pressure side. This means that, as a gap exists between the end
face 41a of the groove 41 and the end face 53a of the tip seal 53
at the end part 10d of the revolving scroll lap 53, the leakage of
the compressed fluid in the direction of arrow 78 is possible, and
also the leakage as shown by arrow 77 is possible from the passage
51.
[0015] Therefore, as shown in FIG. 10 and FIG. 12(a), the high
pressure fluid leaks from the succeeding stage compression section
to the preceding stage compression section through the gap 80 shown
by arrow 29 and 76 to be taken into the preceding stage compression
section to be compressed again, which causes problems of high
temperature and excessive power requirement for compression.
SUMMARY OF THE INVENTION
[0016] The present invention was made to solve the problem
mentioned above, the object is to provide the seal construction of
a multi-stage compression type scroll fluid machine for preventing
the leakage of high pressure compressed fluid to the preceding
stage compression section from the succeeding stage compression
section.
[0017] To solve the problem mentioned above, the present invention
offers a scroll fluid machine with multistage compression section
in which the fluid compressed in the preceding stage compression
section is further compressed in the succeeding stage compression
section characterized in that:
[0018] a lap groove is formed spiraling from the vicinity of the
discharge port of the compressed fluid of the final stage
compression space to the fluid take-in side of the initial stage
compression space, in the tip of the lap being formed a tip seal
grove to receive a seal element, and a rand is formed between the
discharge port at the compression end part of said preceding stage
compression section and the suction port of the succeeding stage
compression section; and
[0019] an intermediate seal element is received in the intermediate
groove formed on the surface of said rand which faces the end plate
of the mating scroll for preventing the leakage of the compressed
fluid from said succeeding stage compression section to said
discharge port opening side of said preceding stage compression
section.
[0020] In the present invention, the scroll lap on the tip of which
is located a tip seal which contacts and slide on the mating scroll
end plate, is formed spirally from the vicinity of the discharge
port of compressed fluid in the final stage compression space
toward the take-in side of the initial stage compression section
forming lap grooves between said lap and the adjacent lap of the
mating scroll; and a rand is formed between the discharge port at
the end part of the lap groove of said preceding stage compression
section and the suction port at the starting part of the lap groove
of said succeeding stage compression section. The compressed fluid
discharged from said discharge port is introduced in said
succeeding stage compression section from said suction port via an
intermediate passage provided with a cooler.
[0021] Said rand may be formed in the stationary scroll or in the
revolving scroll.
[0022] In the tip groove of the lap is received a tip seal which is
pushed by fluid pressure against the mirror surface of the mating
scroll end plate, so a gap is produced between said mirror face of
the mating scroll end plate and the surface of said rand, and said
discharge port opening is communicated through said gap with said
suction port opening. Therefore, the compressed fluid leaked from
space S6, T6, and T8 as shown by arrow 29 and 76 toward said
suction port opening of the succeeding stage compression section
(the leak passage is explained in FIGS. 11, 12) advances toward
said discharge port opening of the preceding stage compression
section. But, according to the present invention, an intermediate
seal element is provided on the rand between said suction port
opening and said discharge opening, so the leakage of the
compressed fluid toward the discharge port opening side is
prevented.
[0023] The seal element consists of a tip seal received in the tip
groove formed in the spiral lap and an intermediate seal element
received in the grove formed in the rand between the discharge port
opening and the suction port opening.
[0024] As shown in FIG. 2 for example, the seal element 26 (tip
seal) seals to partition the lap groove in the succeeding stage
compression section, a seal element 14 (tip seal) seals to
partition the lap groove in the preceding stage compression
section, and an intermediate seal element 25 seals the gap between
the rand and the mating scroll end plate. The seal element 26 is
the extension of the seal element 14.
[0025] It is suitable to form the intermediate seal element as
circular seal element partitioning the succeeding stage compression
section circularly.
[0026] In this case, as shown in FIG. 6 for example, the
intermediate seal element is formed as a closed, single circular
seal, part of which contributes as the intermediate seal on the
rand between the suction and discharge port opening. As the seal
element surrounds completely the succeeding stage compression
section as a single seal element, effective seal between the
succeeding stage compression section and the preceding stage
compression section is performed.
[0027] It is also suitable that the seal element consists of a
first seal element which extends spirally from the fluid take-in
side of said preceding stage compression section side to the final
discharge port side of said succeeding stage compression section
and partitions said discharge port opening and said suction port
opening at said rand surface in the course of its extension; and a
second seal element, an end of which contacts the side face of said
first seal element at the side opposite to said discharge port
opening in the vicinity of said discharge port opening and which
extends from the vicinity of said discharge port opening to the
vicinity of said discharge port opening, surrounding said
succeeding stage compression section to contact the side face of
said first seal element at the side opposite to said suction port
opening.
[0028] It is also suitable that a tip seal groove is formed
extending spirally from the fluid take-in side of said initial
stage compression section toward the compressed fluid discharge
port side of said final stage compression space,
[0029] an intermediate groove is formed communicating with said tip
seal groove in said rand between said discharge port opening and
said suction port opening, a set of seal elements consisting of a
plurality of seal elements is received in said intermediate groove
and said tip seal groove, said seal set consists of;
[0030] a first tip seal which extends from the compressed fluid
discharge port side of said final stage compression space toward
said initial stage compression space via said intermediate
groove,
[0031] a second tip seal which extends parallel with said first tip
seal from the compressed fluid discharge port side of said final
stage compression space to the vicinity of said suction port
opening where the second tip seal depart from said first tip seal
and contacts said first seal in the vicinity of said discharge port
opening, and
[0032] a third tip seal which extends in said tip groove parallel
with said second tip seal from the vicinity of said suction port
opening to partition said succeeding stage compression section
circularly and further extends parallel with said first tip seal
toward said initial stage compression section side.
[0033] With this configuration, as shown in FIG. 8 for example, the
third tip seal 68 is located in the outer side of the second tip
seal 69 which contacts the side face of the first tip seal 67 in
the vicinity of the discharge port opening, so the contact portion
of the first tip seal 67 and the second tip seal 69 is covered by
the third tip seal. Thus, the sealing between the preceding stage
compression section and the succeeding stage compression section is
performed by the first seal element and the second seal element
completely like the case shown in FIG. 6, and the leakage of the
compressed fluid to the preceding stage compression section is
effectively prevented.
[0034] It is also suitable that a tip seal groove is formed
extending spirally from the fluid take-in side of said initial
stage compression section toward the compressed fluid discharge
port side of said final stage compression space,
[0035] an intermediate groove is formed communicating with said tip
seal groove in said rand between said discharge port opening and
said suction port opening, and
[0036] said seal element is a single tip seal received in said tip
seal groove and said intermediate groove.
[0037] With this configuration of the seal element, the prevention
of leakage of the compressed fluid is performed by a single tip
seal, and the number of constituent parts is reduced.
[0038] In addition, as the tip seal can be inserted into the groove
taking the part of the tip seal corresponding to the intermediate
groove as the position basis, it is easier to assemble the tip seal
into the tip groove. First the intermediate part of the seal
element is inserted into the intermediate groove, then the
remaining part can be easily inserted along the tip groove toward
the center side in one hand and toward the outer periphery side on
the other hand.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] FIG. 1 is a cross-sectional view of the scroll fluid machine
of an embodiment according to the present invention.
[0040] FIG. 2 is a perspective view of the scroll housing.
[0041] FIG. 3 is a perspective view of the revolving scroll.
[0042] FIG. 4 is an elevational view in section of the stationary
scroll for explaining the condition of compression of the fluid
when the fluid is taken in by the revolving scroll lap.
[0043] FIG. 5 is an elevational view in section of the stationary
scroll for explaining the condition of compression of the fluid
when the revolving scroll is rotated by 180.degree. from situation
in FIG. 4.
[0044] FIG. 6 is an explanatory representation of the second
embodiment of seal construction according to the present
invention.
[0045] FIG. 7 is an explanatory representation of the third
embodiment of seal construction according to the present
invention.
[0046] FIG. 8 is an explanatory representation of the fourth
embodiment of seal construction according to the present
invention.
[0047] FIG. 9 is an explanatory representation of the fifth
embodiment of seal construction according to the present
invention.
[0048] FIG. 10 is a plan view of scroll for explaining taking-in
action of compressed fluid into the succeeding stage compression
section of the conventional art.
[0049] FIGS. 11(a) and (b) is a partial sectional view along line
A-A and B-B respectively in FIG. 10.
[0050] FIGS. 12(a) and (b) is a partial sectional view along line
C-C and D-D respectively in FIG. 10.
[0051] Reference numeral 1 denotes scroll fluid machine, 2 denotes
stationary scroll housing, 2e denotes discharge port, 2f denotes
suction port, 3 denotes driveshaft housing, 9a denotes rand, 11
denotes revolving scroll, 24 denotes cooling room, 25 denotes
intermediate seal element(seal element), 27 and 28 denote spiral
grooves formed by stationary scroll laps.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0052] A preferred embodiment of the present invention will now be
detailed with reference to the accompanying drawings. It is
intended, however, that unless particularly specified, dimensions,
materials, relative positions and so forth of the constituent parts
in the embodiments shall be interpreted as illustrative only not as
limitative of the scope of the present invention.
[0053] FIG. 1 is a cross-sectional view of the scroll fluid machine
of an embodiment according to the present invention, FIG. 2 is a
perspective view of the scroll housing, FIG. 3 is a perspective
view of the revolving scroll, FIG. 4 is an elevational view in
section of the stationary scroll for explaining the condition of
compression of the fluid when the fluid is taken in by the
revolving scroll lap, FIG. 5 is an elevational view in section of
the stationary scroll for explaining the condition of compression
of the fluid when the revolving scroll is rotated by 180.degree.
from the situation in FIG. 4, FIG. 6 is an explanatory
representation of the second embodiment of seal construction
according to the present invention, FIG. 7 is an explanatory
representation of the third embodiment of seal construction
according to the present invention, FIG. 8 is an explanatory
representation of the fourth embodiment of seal construction
according to the present invention, FIG. 9 is an explanatory
representation of the fifth embodiment of seal construction
according to the present invention.
[0054] In FIG. 1, the multistage type scroll fluid machine body 1
is composed of a stationary scroll housing 2 with a housing cover 4
attached to it and a driveshaft housing 3 to which the stationary
scroll housing 2 is attached.
[0055] A cooling room 24 is provided between a discharge pipe 6
connected to the discharge port of the preceding stage compression
section mentioned later of the stationary scroll housing and the
suction pipe 7 connected to the suction port of the succeeding
stage compression section. The cooling room 24, discharge pipe 6,
and suction pipe 7 connected by piping constitute an intermediate
passage.
[0056] The volume of the intermediate passage from the discharge
port 2e of the preceding stage through the piping passing in the
cooling room to the suction port 2f of the succeeding stage is
determined to be N(integer) times the final compression chamber
volume of the preceding stage compression section. Thus, after N
times of discharge from the final compression chamber of the
preceding stage compression section, the same volume of fluid as
that of the final compression chamber of the preceding stage
compression section is taken into the succeeding stage compression
section.
[0057] However, when the scroll fluid machine is at a standstill at
the start of initial operation, fluid exists in the final
compression chamber of the succeeding stage compression section of
the fluid compression space formed by the stationary scroll lap and
revolving scroll lap at the pressure equal to the outside pressure
at the discharge port 2d(see FIG. 1) or lower.
[0058] The pressure of the fluid in the initial take-in space of
the succeeding stage compression section, as the take-in space
communicates with the intermediate passage, may be reduced to the
take-in pressure of the preceding stage compression section.
[0059] When the initial operation is started in this state, the
fluid residing in the succeeding stage compression section is
compressed to the pressure higher than the outside pressure. That
is, if the pressure when the fluid in the final compression chamber
of the succeeding compression chamber is connected with the fluid
in the compression chamber existing toward the suction port side of
the succeeding compression chamber is higher than the outside
pressure, the fluid is discharged to the outside, but if the
pressure is still lower than the outside pressure, fluid is taken
in from the intermediate passage and the fluid is discharged
together with the fluid in the discharge port side.
[0060] The initial operation comes to end when, after N times of
discharge from the final compression chamber of the preceding stage
compression section, the same volume of fluid as that of the final
compression chamber of the preceding stage compression section is
taken-in into the initial chamber of the succeeding stage
compression section.
[0061] The stationary scroll housing 2 is formed into a shape of
circular tray as shown in FIG. 2. Three ears 2i, 2j, 2k are formed
on the periphery of the housing 2 for connecting the driveshaft
housing 3 fitting to the mating surface 2m of the housing 2 with
bolts. The bottom of concave of the housing 2 is finished to a
mirror surface 2c which communicates with the suction port 2a
formed in the ear 2i.
[0062] A circular groove is formed on the mating surface 2m and a
dust seal 12 made of material having self lubricating property such
as fluororesin and the like is received in the groove.
[0063] On the mirror surface 2c are provided a discharge port 2e of
preceding stage (see FIGS. 4, 5) which communicates with the
discharge pipe 6 shown in FIG. 1, and a suction port 2f of the
succeeding stage (see FIGS. 4, 5) which communicates with the
suction pipe 7. A stationary scroll lap 9b extends spirally in a
counterclockwise direction from the rand 9a between these ports to
form the preceding stage compression section and a stationary
scroll lap 9c extends spirally in a clockwise direction from the
rand 9a to form the succeeding stage compression section, embedded
on the mirror surface 2c. A groove is formed in the tip of each
lap, and a tip seal 14 made of material having self lubricating
property such as fluororesin and the like is received in each
groove.
[0064] An intermediate seal element 25 made of material having self
lubricating property such as fluororesin and the like is provided
on the rand 9a between the tip seal 14, 14. The intermediate seal
element 25 is to prevent the high pressure compressed fluid from
being leaked to the preceding stage compression section side and
compressed and again fed back to the succeeding stage compression
section.
[0065] Cooling fins 2b are formed on the rear side of the mirror
face 2c of the stationary scroll housing 2 as shown in FIG. 1. On
the tip of the cooling fins 2b is attached the housing cover 4 to
form cooling passages 2n. Therefore, the stationary scroll is
cooled by the cooling air flowing in the direction penetrating the
sheet.
[0066] A revolving scroll 11 has a mirror face 10c on which a
revolving scroll lap 10a for forming the preceding stage
compression section in the outer side region and a revolving scroll
lap 10b for forming the succeeding stage compression section in the
center side region are embedded. The revolving scroll 11 is
disposed so that the mirror face 10c contacts the dust seal 12
provided on the mating face of the stationary scroll housing 2. A
groove is formed in the tip of each lap and a tip seal 13 made of
material having self lubricating property such as fluororesin and
the like is received in each groove.
[0067] The revolving scroll 11 is disposed so that the walls of the
revolving scroll lap 10a, 10b face the walls of the stationary
scroll lap 9b, 9c respectively.
[0068] Cooling fins 11a are formed on the rear side of the mirror
face as shown in FIG. 1. On the tip of the cooling fins is attached
an auxiliary cover 15 to form cooling passages 11n. Therefore, the
revolving scroll is cooled by the cooling air flowing in the
direction penetrating the sheet.
[0069] A bearing 18 which supports for rotation the eccentric 16a
formed at the end of a rotation driveshaft 16 mentioned later is
located in the center of the auxiliary cover 15, and in the
periphery side thereof are located bearings 19 at the positions
equally divided in three along a circumference to support crank
assemblies to prevent the rotation of the revolving scroll.
[0070] Each crank assembly is composed of a plate 21 having on the
one side a shaft 22 supported by the bearing 19 and on the other
side a shaft 23 offset in relation to the shaft 22.
[0071] The shaft 23 is supported by a bearing 20 located in the
driveshaft housing 3. The eccentric 16a revolves around the center
axis of the rotation driveshaft 16 as the shaft 16 rotates, and the
revolving scroll 11 performs revolving motion in relation to the
stationary scroll.
[0072] The driveshaft housing 3 has an opening on its side to
introduce cooling air in the direction penetrating the sheet on
which FIG. 1 is depicted for cooling the cooling fins 11a of the
revolving scroll. The rotation drive shaft 16 is supported by a
bearing 17 for rotation in the center of the driveshaft housing 3
and connected with the rotation shaft of a motor not shown in the
drawing.
[0073] With the construction mentioned above, the revolving scroll
revolves as the rotation shaft 16 rotates, and as shown in FIG. 4,
the fluid sucked from the suction port 2a of the stationary scroll
housing 2 is taken in by the revolving scroll lap 10a to be trapped
in the enclosed space S1 and T1 formed by the revolving scroll lap
10a and stationary scroll lap 9b.
[0074] These two enclosed space is different in phase by
180.degree. but the volume is about the same.
[0075] The enclosed spaces move as the revolving scroll revolves as
shown in FIGS. 4 and 5. The fluid taken-in in the enclosed space S1
in FIG. 4 is compressed sequentially from S1 to
S2.fwdarw.S3.fwdarw.S4.fwdarw.S5, from S5 to the preceding stage
discharge port 2e.fwdarw.intermediate passage.fwdarw.succeeding
stage suction port 2f.fwdarw.S6.fwdarw.S7.fwdar- w.S8.fwdarw.S9,
the fluid taken-in in the enclosed space T1 in FIG. 4 is compressed
sequentially from T1 to T2.fwdarw.T3.fwdarw.T4, from T4 to the
preceding stage discharge port 2e.fwdarw.intermediate
passage.fwdarw.succeeding stage suction port
2f.fwdarw.T5.fwdarw.T6.fwdar- w.T7.fwdarw.T8.fwdarw.T9, and the
compressed fluid in the space S9 and T9 are discharged together
from the discharge port 2d in the center to a pipe 8 to be sent
out.
[0076] Since the volume of the final compression space of S side
and T side is the same, the fluid of the same pressure is
discharged from S side final compression space and T side final
compression space through the discharge port 2d.
[0077] As the intermediate seal element 25 made of material having
self lubricating property such as fluororesin and the like is
located between the tip seal 14 and 14 as shown in FIG. 2, the high
pressure compressed fluid is prevented by the intermediate seal
element 25 from being leaked to the preceding stage compression
section side and compressed and again fed back to the succeeding
stage compression section.
[0078] FIG. 6 shows the second embodiment of seal construction.
Instead of the tip seal 14 in the first embodiment, tip seals
consisting of a tip seal 63 of the preceding stage compression
section, a tip seal 65A of the succeeding stage compression
section, and an intermediate seal 64 are used. The intermediate
seal 64 partitions the preceding stage discharge port 2e and the
succeeding stage suction port 2f and encircles the succeeding stage
compression section. So, the leakage of high pressure fluid to the
preceding stage compression section as shown by arrow 29 in FIG. 6
is prevented.
[0079] FIG. 7 shows the third embodiment of seal construction. In
the embodiment, tip seals consisting a tip seal 65B extending from
the preceding stage compression section to the succeeding stage
compression section and a tip seal 66 encircling the succeeding
stage compression section are used. The ship seal 65B partitions
the preceding stage discharge port 2e and the succeeding stage
suction port 2f. So, the leakage of high pressure fluid to the
preceding stage compression section as shown by arrow 29 in FIG. 7
is prevented.
[0080] FIG. 8 shows the fourth embodiment of seal construction. In
the embodiment, three tip seals 67, 68, and 69 are used. The tip
seal 67 extends from the preceding stage compression section to the
succeeding stage compression section. The tip seal 69 is located
together with the tip seal 67 from the succeeding stage discharge
port 2e to the succeeding stage suction port 2f, then surrounds the
outer side of the succeeding stage compression section together
with the tip seal 68 until the preceding stage discharge port 2e.
The tip seal 68 surrounds the outer side of the succeeding stage
compression section together with the tip seal 69 until the
preceding stage discharge port 2e, then is located together with
the tip seal 67. So, the leakage of high pressure fluid to the
preceding stage compression section as shown by arrow 29 in FIG. 8
is prevented.
[0081] FIG. 9 shows the fifth embodiment of seal construction. In
the embodiment, a single tip seal 70 is received in the groove
formed in the tip of the lap. A vacant space 71 is formed in the
rand 9a, and the cross-sectional area of the tip seal 70 is about
same all along the seal to prevent distortion. As the tip seal 70
is formed as a single seal element, the leakage of high pressure
fluid to the preceding stage compression section as shown by arrow
29 in FIG. 9 is effectively prevented.
[0082] According to the embodiments described above, a seal element
which contacts the face of the end plate of a mating scroll with
contact pressure is located on the surface of the rand between the
preceding stage discharge port and the succeeding stage suction
port, and the leakage of high pressure fluid to the discharge port
side of the preceding stage compression section is prevented.
* * * * *