U.S. patent application number 14/587738 was filed with the patent office on 2015-07-09 for electric compressor.
This patent application is currently assigned to KABUSHIKI KAISHA TOYOTA JIDOSHOKKI. The applicant listed for this patent is KABUSHIKI KAISHA TOYOTA JIDOSHOKKI. Invention is credited to Yoshikazu FUKUTANI, Hiroki NAGANO, Ken SUITOU.
Application Number | 20150192126 14/587738 |
Document ID | / |
Family ID | 53443394 |
Filed Date | 2015-07-09 |
United States Patent
Application |
20150192126 |
Kind Code |
A1 |
NAGANO; Hiroki ; et
al. |
July 9, 2015 |
ELECTRIC COMPRESSOR
Abstract
There is provided an electric compressor includes a compression
mechanism, an electric motor, a motor housing having an injection
port that communicates with one of compression chambers that is in
the middle of the compression, a discharge housing having a
discharge chamber into which compressed refrigerant is discharge,
and an intermediate pressure housing disposed between the motor
housing and the discharge housing. The intermediate pressure
housing has an introduction port for introducing intermediate
pressure refrigerant from an external refrigerant circuit and a
communication passage between the introduction port and the
injection port of the motor housing. The introduction port and the
communication passage cooperate with the injection port to allow
the intermediate pressure refrigerant to be injected into the
compression chamber. The communication passage has in the middle
thereof a muffler chamber. A partition member separates the muffler
chamber and the discharge chamber.
Inventors: |
NAGANO; Hiroki; (Aichi-ken,
JP) ; FUKUTANI; Yoshikazu; (Aichi-ken, JP) ;
SUITOU; Ken; (Aichi-ken, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA TOYOTA JIDOSHOKKI |
Kariya-shi |
|
JP |
|
|
Assignee: |
KABUSHIKI KAISHA TOYOTA
JIDOSHOKKI
Kariya-shi
JP
|
Family ID: |
53443394 |
Appl. No.: |
14/587738 |
Filed: |
December 31, 2014 |
Current U.S.
Class: |
417/410.5 |
Current CPC
Class: |
F04C 29/042 20130101;
F04C 23/008 20130101; F04C 18/0215 20130101; F04C 2240/30 20130101;
F04C 29/128 20130101; F04C 29/12 20130101; F04C 29/0035
20130101 |
International
Class: |
F04C 18/02 20060101
F04C018/02; F04C 29/12 20060101 F04C029/12; F04C 29/00 20060101
F04C029/00; F04C 25/00 20060101 F04C025/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 8, 2014 |
JP |
2014-001483 |
Claims
1. An electric compressor comprising: a compression mechanism
having a plurality of compression chambers; an electric motor
driving the compression mechanism to draw refrigerant into the
compression chambers and compress the refrigerant in the
compression chambers; a motor housing accommodating the electric
motor and the compression mechanism, the motor housing having an
injection port that communicates with one of the compression
chambers, the compression chamber being in the middle of the
compression; a discharge housing having a discharge chamber into
which the compressed refrigerant is discharge; and an intermediate
pressure housing disposed between the motor housing and the
discharge housing, the intermediate pressure housing having an
introduction port for introducing intermediate pressure refrigerant
from an external refrigerant circuit and a communication passage
that provides communication between the introduction port and the
injection port of the motor housing, wherein the introduction port
and the communication passage cooperate with the injection port to
allow the intermediate pressure refrigerant to be injected into the
compression chamber, wherein the communication passage has in the
middle thereof a muffler chamber whose volume is large than volume
of the communication passage other than the muffler chamber,
wherein pressure of the intermediate pressure refrigerant is higher
than pressure of the drawn refrigerant and lower than pressure of
the compressed refrigerant discharged into the discharge chamber,
wherein a partition member separates the muffler chamber and the
discharge chamber.
2. The electric compressor according to claim 1, wherein the
partition member has a bottom plate and a side wall that extends
from the bottom plate toward the intermediate pressure housing and
is surrounded by the discharge chamber.
3. The electric compressor according to claim 1, wherein each of
the motor housing, the discharge housing and the intermediate
pressure housing has a bolt fastening hole, wherein a bolt is
inserted in the bolt fastening holes of the motor housing, the
discharge housing and the intermediate pressure housing to fasten
the motor housing, the discharge housing and the intermediate
pressure housing together.
4. The electric compressor according to claim 1, wherein a recess
is formed in the intermediate pressure housing side of the
discharge housing so as to expand a volume of the discharge
chamber, wherein the recess partially surrounds the muffler
chamber.
5. The electric compressor according to claim 1, wherein the
discharge housing has therein a projection that is formed extending
toward the partition member, wherein a clearance is formed between
the projection and the partition member so as to restrict flow of
the compressed refrigerant from the discharge chamber to the
communication passage.
6. The electric compressor according to claim 5, wherein the
projection has therein a communication passage through which an
outlet port is in communication with the discharge chamber, wherein
the partition member has therein a recess in which the projection
is inserted, wherein the communication passage of the projection
has an opening in the recess, wherein the clearance is formed
between the projection and the recess of the partition member.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to an electric
compressor and specifically to an electric compressor with an
injection mechanism.
[0002] Japanese Patent Application Publication No. H08-303361
discloses a scroll type compressor including a power save mechanism
that controls the displacement of the compressor by allowing
refrigerant gas being compressed to flow to low pressure region of
the compressor through a bypass passage. The power save mechanism
has a cover plate on the upper surface of an end plate of a fixed
scroll member of the compressor. The cover plate has therein a
backpressure passage in which high pressure refrigerant gas and low
pressure gas from a unit circuit are supplied selectively through a
high pressure guide tube and a bypass passage that is in
communication with the backpressure passage. The end plate of the
fixed scroll member has therethrough a first save hole and a second
save hole that are in communication with a compression chamber and
a return hole that is in communication with a low pressure chamber.
The first save hole, the second save hole, and the return hole are
communicable with the bypass passage through a first save valve, a
second save valve, and a valve body that are provided at the
openings of the respective holes adjacent to the bypass passage.
The first save valve, the second valve, and the valve body can be
opened and closed in response to the pressure of the refrigerant
gas supplied into the bypass passage.
[0003] According to the pressure of the refrigerant gas supplied
into the bypass passage through the backpressure passage from the
high pressure guide tube, the opening and closing of the first save
valve, the second valve, and the valve body are controlled. When
high pressure refrigerant gas is supplied into the bypass passage
from the high pressure guide tube through the backpressure passage,
the first save valve, the second valve, and the valve body are
moved in the directions that close the first save hole, the second
save hole, and the return hole, respectively. When low pressure
refrigerant gas is supplied into the bypass passage from the high
pressure guide tube through the backpressure passage, the first
save valve, the second save valve, and the valve body are moved in
the directions that open the first save hole, the second save hole,
and the return hole, respectively.
[0004] In the scroll type compressor according to the above-cited
Publication, the bypass passage needs to be extended for the
pressure of refrigerant gas supplied into the bypass passage from
the high pressure guide tube through the backpressure passage to be
stable. Though the thickness of the cover plate needs to be
increased for extending the bypass passage, there is no space
between the end cap of the compressor and the cover plate that is
large enough for extending the bypass passage adequately. If the
bypass passage is extended, the space for the discharge chamber
formed between the end cap and the cover plate is decreased.
[0005] The present invention, which has been made in light to the
above problems, is directed to providing an electric compressor
that can easily increase the volume of its injection chamber and
efficiently decrease the pressure pulsation of intermediate
pressure refrigerant introduced into the injection chamber.
SUMMARY OF THE INVENTION
[0006] In accordance with an aspect of the present invention, there
is provided an electric compressor includes a compression mechanism
having a plurality of compression chambers, an electric motor
driving the compression mechanism to draw refrigerant into the
compression chambers and compress the refrigerant in the
compression chambers, a motor housing accommodating the electric
motor and the compression mechanism, the motor housing having an
injection port that communicates with one of the compression
chambers that is in the middle of the compression, a discharge
housing having a discharge chamber into which the compressed
refrigerant is discharge, and an intermediate pressure housing
disposed between the motor housing and the discharge housing. The
intermediate pressure housing has an introduction port for
introducing intermediate pressure refrigerant from an external
refrigerant circuit and a communication passage that provides
communication between the introduction port and the injection port
of the motor housing. The introduction port and the communication
passage cooperate with the injection port to allow the intermediate
pressure refrigerant to be injected into the compression chamber.
The communication passage has in the middle thereof a muffler
chamber whose volume is large than volume of the communication
passage other than the muffler chamber. Pressure of the
intermediate pressure refrigerant is higher than pressure of the
drawn refrigerant and lower than pressure of the compressed
refrigerant discharged into the discharge chamber. A partition
member separates the muffler chamber and the discharge chamber.
[0007] Other aspects and advantages of the invention will become
apparent from the following description, taken in conjunction with
the accompanying drawings, illustrating by way of example the
principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The invention together with objects and advantages thereof,
may best be understood by reference to the following description of
the presently preferred embodiments together with the accompanying
drawings in which:
[0009] FIG. 1 is a longitudinal sectional view of an electric
compressor according to an embodiment of the present invention;
[0010] FIG. 2 is a sectional view taken along the line A-A of FIG.
1;
[0011] FIG. 3 is an enlarged sectional view of a valve block of the
electric compressor of FIG. 1;
[0012] FIG. 4 is a sectional view taken along the line B-B of FIG.
1;
[0013] FIG. 5 is a sectional view taken along the line C-C of FIG.
1;
[0014] FIG. 6 is a perspective view of a partition member of the
electric compressor of FIG. 1;
[0015] FIG. 7 is a longitudinal sectional view showing a state
where the partition member is mounted in the electric compressor of
FIG. 1; and
[0016] FIG. 8 is a longitudinal sectional view showing a state
where a partition member of an electric compressor according to
another embodiment of the present invention is mounted.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0017] The following will describe an electric compressor of an
embodiment according to the present invention with reference to
FIGS. 1 through 8. The electric compressor of the present
embodiment is a scroll type electric compressor that is mounted on
an electric vehicle (hereinafter referred to merely as the electric
compressor). The electric compressor forms a part of the
refrigerant circuit of a vehicle air-conditioner.
[0018] Referring to FIG. 1, the electric compressor that is
designated by numeral 10 integrally includes a compression
mechanism 11 compressing refrigerant as fluid and an electric motor
12 for driving the compression mechanism 11. The electric
compressor 10 further includes a housing assembly 13 that is made
of metal. In the present embodiment, the housing assembly 13 is
made of an aluminum alloy. The housing assembly 13 includes a motor
housing 14, a valve block 15, and a discharge housing 16. The valve
block 15 forms a part of an outer shell of the housing assembly 13.
It is noted that the valve block 15 corresponds to the intermediate
pressure housing of the present invention. The motor housing 14,
the valve block 15, and the discharge housing 16 are connected
together by bolts 17.
[0019] The motor housing 14 has at the end thereof that is adjacent
to the valve block 15 a plurality of bolt holes 53 that extend
parallel to the axial direction of the electric compressor 10 and
are spaced at an interval in the circumferential direction of the
motor housing 14. The bolt 17 is inserted in the bolt hole 53 and
screwed, so that the motor housing 14, the valve block 15, and the
discharge housing 16 are fastened together. It is noted that the
bolt hole 53 corresponds to the bolt fastening hole of the present
invention. Specifically, a plurality of sets of holes 61, 57 and 53
is formed in the discharge housing 16, the valve block 15 and the
motor housing 14, respectively, in axial direction of the electric
compressor 10 at positions that are spaced at an interval in the
circumferential direction of the housing assembly 13. Each bolt 17
is inserted through the holes 61, 57 and screwed into the bolt hole
53 thereby to fasten the motor housing 14, the valve block 15, and
the discharge housing 16 together. The holes 53, 57, 61 correspond
to the bolt fastening holes of the present invention.
[0020] The motor housing 14 of the electric compressor 10 has
therein the compression mechanism 11 and the electric motor 12. The
compression mechanism 11 includes a fixed scroll member 18 and a
movable scroll member 19. A compression chamber 20 is formed by the
fixed scroll member 18 and the movable scroll member 19. The motor
housing 14 has therethrough an inlet port 21. The inlet port 21 is
connected to an external refrigerant circuit (not shown in the
drawing). Low pressure refrigerant is flowed from the external
refrigerant circuit through the inlet port 21 into the motor
housing 14 during the operation of the electric compressor 10.
[0021] A shaft support member 22 is provided in the motor housing
14 between the fixed scroll member 18 and the electric motor 12.
The shaft support member 22 forms a part of the compression
mechanism 11 and has therein a bearing 24 that supports one end of
a rotary shaft 23 of the electric motor 12. The other end of the
rotary shaft 23 is supported by the motor housing 14 through a
bearing 25. The shaft support member 22 has therethrough a suction
port 26 that provides fluid communication between the interior of
the motor housing 14 and the compression chamber 20. The
refrigerant drawn into the motor housing 14 through the inlet port
21 is introduced through the suction port 26 into the compression
chamber 20. The shaft support member 22 has fixed pins 27
press-fitted in the holes formed in the shaft support member 22 and
extending toward the movable scroll member 19.
[0022] The rotary shaft 23 has at one end thereof adjacent to the
fixed scroll member 18 an eccentric pin 28 extending from the end
toward the fixed scroll member 18. The axis Q of the eccentric pin
28 is offset from the axis P of the rotary shaft 23. When the
rotary shaft 23 rotates, the eccentric pin 28 is rotated
eccentrically with respect to the axis P of the rotary shaft 23. A
drive bush 29 is relatively rotatably mounted on the eccentric pin
28. The drive bush 29 has a balancing weight that balances the
eccentric load of the eccentric pin 28 and the drive bush 29
developed by the rotation of the rotary shaft 23.
[0023] The movable scroll member 19 is rotatably mounted on the
drive bush 29 through a bearing 30, so that the movable scroll
member 19 can make an orbital motion with the rotation of the
rotary shaft 23. The movable scroll member 19 includes a circular
movable base plate 31 and a movable scroll wall 32. The movable
scroll member 19 is disposed such that the surface of the movable
base plate 31 extends perpendicularly to the axis P. The movable
scroll wall 32 is formed extending from the surface of the movable
base plate 31 on the side thereof that is adjacent to the fixed
scroll member 18.
[0024] As shown in FIG. 1, a plurality of bottomed cylindrical
holes 33 is formed in the movable base plate 31 of the movable
scroll member 19 at positions adjacent to the outer peripheral edge
of the movable base plate 31. A plurality of anti-rotation rings 34
is inserted in the respective bottomed cylindrical holes 33.
[0025] The fixed pins 27 are located at positions in the shaft
support member 22 that correspond to the respective bottomed
cylindrical holes 33. Each fixed pin 27 extends from the shaft
support member 22 toward the bottomed cylindrical hole 33 and is
inserted into the anti-rotation ring 34. In the present embodiment,
the anti-rotation ring 34 and the fixed pins 27 form the
anti-rotation mechanism for preventing the movable scroll member 19
from rotating on its axis. Therefore, the movable scroll member 19
orbits around the axis P without rotating on its axis with the
rotation of the rotary shaft 23. That is, the movable scroll member
19 is provided so as to make an orbital movement around the axis P
without rotation.
[0026] The fixed scroll member 18 is engaged with the movable
scroll member 19 in facing relation to each other and fixed to the
motor housing 14. The fixed scroll member 18 has a circular fixed
base plate 35 and a fixed scroll wall 36. The fixed base plate 35
and the fixed scroll wall 36 of the fixed scroll member 18 are
integrally formed. The fixed base plate 35 is disposed in the motor
housing 14 so as to close the end of the motor housing 14. The
fixed scroll wall 36 is formed extending from the surface of the
fixed base plate 35 on the side thereof that is adjacent to the
movable scroll member 19. The fixed base plate 35 forms a part of
the motor housing 14.
[0027] In the electric compressor 10 according to the present
embodiment, the compression chambers 20 are formed between the
fixed scroll member 18 and the movable scroll member 19 by the
contact engagement of the fixed scroll wall 36 of the fixed scroll
member 18 and the movable scroll wall 32 of the movable scroll 19.
As shown in FIG. 2, two compression chambers 20 of the same volume
and pressure are formed simultaneously. Refrigerant is introduced
through the suction port 26 into two compression chambers 20 formed
at positions adjacent to the outer periphery of the electric
compressor 10. The orbiting motion of the movable scroll member 19
causes the two compression chambers 20 to move toward the center,
so that the volume of the compression chambers 20 is decreased and
the refrigerant in the compression chambers 20 is compressed. The
fixed scroll member 18 has at the center thereof a discharge port
37 having a discharge valve 38 that opens and closes the discharge
port 37 and a retainer 56 that regulates the opening of the
discharge valve 38. The discharge valve 38 is opened when the
pressure of the refrigerant compressed in the compression chambers
20 becomes greater than a predetermined pressure.
[0028] As shown in FIGS. 1 and 2, the fixed base plate 35 of the
fixed scroll member 18 has therein two injection ports 39 that are
formed radially outward of the discharge port 37 in communication
with the compression chambers 20 that are then in the middle of
compression, and have an opening at a position adjacent to the
valve block 15. The injection port 39 is a passage through which
intermediate pressure refrigerant is introduced into the
compression chamber 20. The injection ports 39 are formed in
communication with the compression chambers 20 that are then in the
phase of compression. The diameter of the injection port 39
adjacent to the movable scroll member 19 is smaller than that of
the injection port 39 adjacent to the valve block 15, so that
intermediate pressure refrigerant in the injection port 39 is
injected into the compression chamber 20. The small diameter
portion of the injection port 39 serves as a nozzle.
[0029] The electric motor 12 includes a stator 40 fixed on the
inner peripheral surface of the motor housing 14 and a rotor 41
fixed on the rotary shaft 23. The electric compressor 10 has a
drive circuit case 65 connected to the motor housing 14. The drive
circuit case 65 has therein a drive circuit 64 that drives the
electric motor 12. Three-phase AC power is supplied from the drive
circuit 64 to a coil 40A of the stator 40 and the rotor 41 is
rotationally driven by power supplied to the coil 40A of the stator
40 and the rotor 41 is driven to rotate, accordingly. With the
rotation of the rotor 41, the compression mechanism 11 that is
operatively connected to the rotary shaft 23 is operated for
compression of refrigerant.
[0030] As shown in FIGS. 1 and 3, the valve block 15 has a
cylindrical shape and a predetermined thickness in the axial
direction of the rotary shaft 23. The valve block 15 is made of an
aluminum alloy. As shown in FIG. 3, the valve block 15 has a front
surface 7 facing the motor housing 14, a rear surface 8 facing the
discharge housing 16, and a peripheral wall 9 formed between the
front surface 7 and the rear surface 8. As shown in FIGS. 3 and 4,
the valve block 15 has in the center thereof a rectangular recess
42 that is recessed in the radial direction of the rotary shaft 23
and has an opening adjacent to the discharge housing 16. A step
portion 43 is formed in the recess 42 at a position adjacent to the
bottom of the recess 42. A muffler chamber 45 (injection chamber)
is formed by closing the opening of the recess 42 by a partition
member 44. The muffler chamber 45 serves as a muffler that reduces
the pressure pulsation of the intermediate pressure refrigerant
introduced into the muffler chamber 45. It is noted that the
partition member 44 will be described in detail later.
[0031] As shown in FIG. 3, the muffler chamber 45 has therein a
check valve 46. The check valve 46 is formed by a valve plate 47
having a hole 47A, a reed valve 48 disposed so as to cover the hole
47A, and a retainer 49 regulating the opening of the reed valve 48.
The check valve 46 is fastened to the step portion 43 by bolts 50.
The muffler chamber 45 is divided into two spaces by the check
valve 46, namely the space S1 on the discharge housing 16 side of
the check valve 46 and the space S2 on the motor housing 14 side of
the check valve 46.
[0032] The valve block 15 has therein an introduction port 51 that
is in communication with the space S1 of the muffler chamber 45 and
has an opening at the outer periphery of the valve block 15. The
introduction port 51 serves as a passage through which intermediate
pressure refrigerant is introduced from an eternal refrigerant
circuit (not shown in the drawing). The intermediate pressure
refrigerant introduced through the introduction port 51 is flowed
into the muffler chamber 45. The external refrigerant circuit
includes an evaporator and a condenser and a part of the
refrigerant having intermediate pressure decompressed between the
evaporator and the condenser and having an intermediate pressure is
introduced through a high pressure guide tube (not shown in the
drawing) into the introduction port 51. Intermediate pressure
refrigerant refers to refrigerant whose pressure is higher than
suction pressure of refrigerant drawn at the inlet port 21 and
lower than discharge pressure of refrigerant at the discharge port
37.
[0033] The valve block 15 has therein two supply ports 52 that are
formed between the bottom surface of the recess 42 and the front
surface 7 of the valve block 15 in communication with the
respective injection ports 39 formed in the fixed scroll member 18
and also with the space S2 of the muffler chamber 45. When
intermediate pressure refrigerant is introduced through the
introduction port 51 into the space S1 of the muffler chamber 45,
the reed valve 48 is bent to open by the pressure of the
refrigerant. Accordingly, the intermediate pressure refrigerant in
the space S1 of the muffler chamber 45 is supplied through the
space S2 of the muffler chamber 45, the supply port 52, and the
injection port 39 into the compression chamber 20. Then, the
intermediate pressure of refrigerant is higher than the pressure of
the compression chamber 20 into which the intermediate pressure
refrigerant is to be supplied. The introduction port 51, the
muffler chamber 45 (51, S2), and the supply port 52 cooperate to
form a communication passage through which the introduction port 51
is in communication with the injection port 39. The muffler chamber
45 is provided in the middle of the communication passage and
formed as an expanded space.
[0034] A recess 66 is formed in the valve block 15 on the side
thereof opposite from the muffler chamber 45 and has an opening at
the end adjacent to the discharge port 37 and a discharge valve
chamber 55 is formed by closing the recess 66 of the valve block 15
covered by the fixed scroll member 18. The discharge valve chamber
55 has therein the discharge valve 38 and the retainer 56 for the
discharge port 37. The valve block 15 has therein a passage 6
(refer to FIG. 1) through which the discharge valve chamber 55 is
in communication with the discharge chamber 58.
[0035] Thus, the introduction port 51, the muffler chamber 45, the
check valve 46, and the supply port 52 are all formed in the valve
block 15. The introduction port 51, the muffler chamber 45, the
check valve 46, and the supply port 52 cooperate to form the
injection mechanism. The injection mechanism serves as a mechanism
that allows the refrigerant of an intermediate pressure that is
higher than the suction pressure and lower than the discharge
pressure of refrigerant to be introduced into the compression
chamber 20 that is then in the middle of compression.
[0036] As shown in FIGS. 1 and 5, the discharge housing 16 has
therein a circular recess 62 that is opened toward the valve block
15. A projection 73 is formed extending from the bottom of the
recess 62 toward the valve block 15. The recess 62 of the discharge
housing 16 is closed the valve block 15, thereby forming a space
that corresponds to the discharge chamber 58. The discharge housing
16 has therein a discharge port 60 that is formed at a position
adjacent to the bottom of the recess 62 and opened at the outer
periphery of the discharge housing 16. The discharge port 60 has an
outlet port 59 at the outer periphery of the discharge port 60. The
outlet port 59 is connected to the external refrigerant circuit
(not shown in the drawing). The discharge housing 16 further has
therein a communication passage 74 that is formed in the center of
the projection 73 and through which the discharge chamber 58 is in
communication with the discharge port 60. The communication passage
74 is formed parallel to the axial direction of the rotary shaft
23. The discharge housing 16 has therein a hole 61 that is disposed
at a position adjacent to the outer periphery of the discharge
housing 16 and through which the bolt 17 is inserted parallel to
the axial direction of the rotary shaft 23. The plural holes 61 are
equally spaced in the circumferential direction of the discharge
housing 16. The holes 61 are formed at the same position in the
circumferential direction of the discharge housing 16 as the bolt
holes 53 formed at the end of the motor housing 14. It is noted
that the hole 61 corresponds to the bolt fastening hole.
[0037] As shown in FIGS. 1 and 3, the partition member 44 is
provided between the valve block 15 and the discharge housing 16.
Connecting the valve block 15 and the discharge housing 16 through
the partition member 44 forms the discharge chamber 58 and the
muffler chamber 45 separately. That is, the partition member 44 has
a function that partitions between the discharge chamber 58 and the
muffler chamber 45. The muffler chamber 45 is located on the
opposite side of the partition member 44 from a part of the
discharge chamber 58. It is noted that the two-dot chain line
designated by 75 in FIG. 3 shows a plate-shaped partition member
according to the prior art.
[0038] Referring to FIGS. 6 and 7, the partition member 44 is
generally of a box shape and includes bottom portions 67, 68, and a
side wall portion 69 that forms the periphery of the partition
member 44. The side wall portion 69 is formed extending axially
from the bottom portions 67, 68 toward the valve block 15 and
surrounded by the discharge chamber 58. A step 77 is formed between
the bottom portions 67, 68. In the partition member 44, the bottom
portions 67, 68 and the side wall portion 69 are formed extending
into the discharge housing 16. As shown FIG. 3, the distance L1
between the rear surface 8 of the valve block 15 and the outer
surface of the bottom portion 67 is larger than the distance L2
between the rear surface 8 and the outer surface of the bottom
portion 68. The bottom portion 68 has therein an arcuate recess 71.
The recess 71 includes a flat bottom portion 71A and a wall portion
71B formed around the bottom portion 71A. A space S3 is formed
surrounded by the bottom portions 67, 68, the step 77, and the side
wall portion 69 and in communication with the space S1 of the
muffler chamber 45. That is, a part of the space S1 of the muffler
chamber 45 is formed extending into the discharge housing 16.
[0039] The side wall portion 69 of the partition member 44 is
formed surrounded by the discharge chamber 58, which increases the
volume of the space S1 of the muffler chamber 45. The partition
member 44 is made of an aluminum alloy. The partition member 44 has
three mounting holes 70 that are disposed on the periphery of the
partition member 44. The partition member 44 is fixed on the valve
block 15 by bolts 54 that are inserted through the mounting holes
70.
[0040] As shown in FIGS. 3 and 4, the valve block 15 has therein a
recess 72 that is formed on the valve block 15 side of the
discharge housing 16 at a position radially outward of the muffler
chamber 45 so as to partially surround the recess 42 and opened to
the discharge housing 16. The recess 72 of the valve block 15 that
is surrounded by the discharge housing 16, as shown in FIG. 7 is in
direct communication with the discharge chamber 58 and forms a part
of the discharge chamber 58. That is, the recess 72 serves to
expand the volume of the discharge chamber 58.
[0041] Referring to FIG. 7, the partition member 44 is disposed in
such a way that the recess 71 in the bottom portion 68 of the
partition member 44 covers a projection side opening 74A of the
communication passage 74 that is located remote from the discharge
port 60 so that a clearance is formed between the end of the
projection 73 and the surface of the bottom portion 71A of the
recess 71 and also a clearance is formed between the outer
peripheral surface 73A of the projection 73 and the wall portion
71B. Thus, the discharge passage extending from the discharge
chamber 58 to the communication passage 74 is restricted between
the projection 73 and the surface of the bottom portion 71A of the
recess 71. Adjusting the depth of the recess 71 (or the clearance
between the end of the projection side opening 74A and the bottom
portion 71A of the recess 71) enables to change the restriction of
the discharge passage. The high pressure refrigerant discharged
into the discharge chamber 58 is flowed through the restricted
passage and the communication passage 74 into the discharge port 60
and discharged through the outlet port 59 into the external
refrigerant circuit.
[0042] For assembling the electric compressor 10, the valve block
15 having incorporated therein the injection mechanism is prepared,
the valve block 15 is set so as to form a part of the housing
assembly 13, and the valve block 15, the motor housing 14, and the
discharge housing 16 are bolted together. That is, the valve block
15 may be disposed between the motor housing 14 and the discharge
housing 16 and integrally fixed by the bolts 17.
[0043] The following will describe the operation of the electric
compressor 10 having the above-described configuration. The rotary
shaft 23 is driven to rotate by the electric motor 12 that is
driven by the drive circuit 64. The rotation of the rotary shaft 23
is transmitted through the eccentric pin 28 and the drive bush 29
to the movable scroll member 19 of the compression mechanism 11.
The movable scroll member 19 performs an orbital movement around
the P without rotation on its own axis by virtue of the
anti-rotation ring 34 and the fixed pin 27 that serve as the
anti-rotation mechanism. The movable scroll member 19 performs an
orbital movement around the axis P without rotation, so that the
compression chamber 20 formed between the movable scroll member 19
and the fixed scroll member 18 is moved toward the center and the
volume of the compression chamber 20 is decreased, accordingly.
[0044] Therefore, refrigerant is flowed through the inlet port 21
into the motor housing 14 and introduced through the suction port
26 into the compression chamber 20. The pressure of the refrigerant
is increased with the volume decrease of the compression chamber
20. The high pressure refrigerant opens the discharge valve 38 and
is discharged through the discharge port 37 into the discharge
valve chamber 55. Then, the refrigerant is flowed through the
discharge valve chamber 55 into the discharge chamber 58.
[0045] Intermediate pressure refrigerant which is introduced from
the external refrigerant circuit through the introduction port 51
into the space S1 of the muffler chamber 45 pushes open the reed
valve 48. Accordingly, the refrigerant in the space S1 of the
muffler chamber 45 is supplied through the space S2 of the muffler
chamber 45, the supply port 52, and the injection port 39 into the
compression chamber 20 that is then in the middle of compression.
Then, the pressure of the refrigerant in the compression chamber 20
in the middle of compression is lower than that of the intermediate
pressure refrigerant.
[0046] Supplying the intermediate pressure refrigerant into the
compression chamber 20 is performed after the pressure pulsation of
the refrigerant in the muffler chamber 45 that serves as a muffler
has been decreased. The side wall portion 69 of the partition
member 44 is formed surrounded by the discharge chamber 58, so that
the volume of the space S1 of the muffler chamber 45 is increased
and the intermediate pressure refrigerant is introduced into the
space S1 of the muffler chamber 45 having an increased volume.
Therefore, the pressure pulsation of the refrigerant can be
efficiently decreased and especially, the noise generation due to
the pressure pulsation can be suppressed. Because intermediate
pressure refrigerant the pressure pulsation of which has been
decreased is supplied into the compression chamber 20, the
operating efficiency of the compressor is improved. In a case that
the refrigerant pressure in the compression chamber 20 is higher
than the pressure of the intermediate pressure refrigerant in the
muffler chamber 45, the check valve 46 is kept closed and supplying
of the intermediate pressure refrigerant into the compression
chamber 20 is not performed. Thus, the check valve 46 prevents
refrigerant from flowing reversely from the compression chamber
20.
[0047] The high pressure refrigerant discharged into the discharge
chamber 58 is flowed through the communication passage 74 into the
discharge port 60 after flowing past the restricted passage between
the projection 73 and the surface of the bottom portion 71A of the
recess 71. For the purpose, the projection 73 is provided with the
end thereof inserted in the recess 71 so that a clearance is formed
between the end of the projection 73 and the surface of the bottom
portion 71A of the recess 71 and also a gap is formed between the
outer peripheral surface 73A of the projection 73 and the wall
portion 71B of the recess 71. Therefore, the discharge passage
extending from the discharge chamber 58 to the communication
passage 74 is restricted between the projection 73 and the surface
of the bottom portion 71A of the recess 71. Referring to the
enlarged part in FIG. 7, the arrow line indicates the flow of
refrigerant flows from the discharge chamber 58 to the
communication passage 74 in the discharge passage. The pressure
pulsation or the discharge pulsation of refrigerant being
discharged from the discharge chamber 58 into the discharge port 60
can be decreased. Especially, there is a fear that the volume of
the discharge chamber 58 is decreased and the discharge pulsation
is increased because the side wall portion 69 of the discharge
chamber 58 is formed so as to be surrounded by the discharge
chamber 58. The discharge passage between the end of the projection
73 and the surface of the bottom portion 71A of the recess 71 is
restricted, so that the discharge pulsation can be decreased.
[0048] The refrigerant discharged into the discharge port 60 is
delivered through the outlet port 59 into the external refrigerant
circuit. Though the volume of the discharge chamber 58 is decreased
due to the structure in which the side wall portion 69 of the
partition member 44 is formed surrounded by the discharge chamber
58, the decreased volume of the discharge chamber 58 can be
compensated by forming the recess 72 in the valve block 15 as a
part of the discharge chamber 58.
[0049] The following will describe the effects of the electric
compressor 10 having the configuration described above. The side
wall portion 69 of the partition member 44 is formed surrounded by
the discharge chamber 58, so that the volume of the muffler chamber
45 serving as a muffler is increased. Because intermediate pressure
refrigerant is introduced into the muffler chamber 45 having the
increased volume, the function of the muffler chamber as a muffler
can be improved and the pressure pulsation of the refrigerant can
be efficiently decreased. Because intermediate pressure refrigerant
with the pressure pulsation decreased is supplied into the
compression chamber 20, variation of refrigerant supply amount due
to the pressure pulsation can be suppressed and operating
efficiency of the compressor can be improved further.
[0050] The partition member 44 includes the bottom portion 67
having the distance L1 as measured between the rear surface 8 of
the valve block 15 and the outer surface of the bottom portion 67,
the bottom portion 68 having the distance L2 as measured between
the rear surface 8 and the outer surface of the bottom portion 68,
wherein L1 is larger than L2, and the side wall portion 69 that
forms the periphery of the partition member 44. The volume of the
muffler chamber 45 can be easily changed by changing the distance
L1 of the bottom portion 67 and the distance L2 of the bottom
portion 68. For example, in the case of the partition member 76
shown in FIG. 8, wherein the distance between the rear surface 8 of
the valve block 15 and the outer surface of the bottom portion 67
of the partition member 76 is smaller than the distance L1 of the
bottom portion 67 of the partition member 44 of FIG. 3. In this
case, the increase of the volume of the muffler chamber 45 is
lessened. Thus, the distances L1, L2 can be easily changed
according to the type of a vehicle on which the electric compressor
10 is to be mounted and the pressure pulsation of refrigerant
introduced into the muffler chamber 45 can be adjusted. As a
result, a higher degree of freedom in setting the volume of the
muffler chamber 45 may be accomplished. The volume of the muffler
chamber 45 can be set according to the condition of a vehicle.
[0051] In assembling the compressor 10, the valve block 15 having
the muffler chamber 45, the check valve 46, and the supply port 52
is prepared and the motor housing 14, the valve block 15, and the
discharge housing 16 are assembled with the valve block 15 disposed
so as to form a part of the housing assembly 13 of the electric
compressor 10. The valve block 15, the motor housing 14, and the
discharge housing 16 are fastened together. Thus, the injection
mechanism can be added easily to an existing compressor.
[0052] The projection 73 is provided with the end thereof inserted
in the recess 71 so that a clearance is formed between the end of
the projection 73 and the surface of the bottom portion 71A of the
recess 71 and also a gap is formed between the outer peripheral
surface 73A of the projection 73 and the wall portion 71B of the
recess 71. Therefore, the discharge passage extending from the
discharge chamber 58 to the communication passage 74 is restricted
in the region between the projection 73 and the surface of the
bottom portion 71A of the recess 71, so that pressure pulsation of
the refrigerant being discharged from the discharge chamber 58 into
the discharge port 60 can be decreased. Especially, there is a fear
that the volume of the discharge chamber 58 is decreased and the
discharge pulsation is increased because the side wall portion 69
of the discharge chamber 58 is formed so as to be surrounded by the
discharge chamber 58. However, the discharge passage between the
end of the projection 73 and the surface of the bottom portion 71A
of the recess 71 is restricted, so that discharge pulsation can be
decreased. Adjusting the depth of the recess 71 or the clearance
between the end of the projection 73 and the surface of the bottom
portion 71A of the recess 71 enables to change the above
clearance.
[0053] Though the volume of the discharge chamber 58 is decreased
due to the structure in which the side wall portion 69 of the
partition member 44 is formed surrounded by the discharge chamber
58, the decreased volume of the discharge chamber 58 can be
compensated by the recess 72 provided in the valve block 15 as a
part of the discharge chamber 58, as well as the large space of the
discharge chamber 58 itself.
[0054] The present invention is not limited to the above-described
embodiment, but it may be modified or embodied variously within the
scope of the invention as exemplified below. In the above-described
embodiment, the partition member 44 has the bottom portion 67
having the larger distance L1, the bottom portion 68 having the
smaller distance L2, and the side wall portion 69 that forms the
periphery of the partition member 44. The shape of the partition
member 44 is not limited to the above-described embodiment, but any
shape may be employed as long as the side wall portion 69 of the
partition member 44 is formed surrounded by the discharge chamber
58. For example, the bottom portions 67, 68 may have an inclined
shape or a swollen shape like a dome. The bottom portions 67, 68
may be formed extending partially toward the discharge housing 16.
In the above-described embodiment, the partition member 44 has been
described as being of made of an aluminum alloy. The partition
member 44 may be made of a resin or any other metal. Especially,
when using a resin, intrinsic vibration frequency of the partition
member 44 may be changed so as to suppress the vibration of the
partition member 44 developed by the pressure pulsation of
refrigerant. In the above-described embodiments, the partition
member 44 is formed extending toward the discharge housing 16. As
long as the muffler chamber 45 has an adequate volume and serves as
a muffler adequately, the partition member 44 may be of a plate
shape. In the above-described embodiment, the valve block 15 forms
a part of the outer shell of the electric compressor 10, but the
valve block 15 may be disposed within the motor housing 14 or in
the discharge housing 16.
* * * * *