U.S. patent application number 14/084152 was filed with the patent office on 2014-05-22 for variable speed scroll compressor.
The applicant listed for this patent is DANFOSS COMMERCIAL COMPRESSORS. Invention is credited to Patrice BONNEFOI, Gael MELDENER.
Application Number | 20140140867 14/084152 |
Document ID | / |
Family ID | 47628200 |
Filed Date | 2014-05-22 |
United States Patent
Application |
20140140867 |
Kind Code |
A1 |
BONNEFOI; Patrice ; et
al. |
May 22, 2014 |
VARIABLE SPEED SCROLL COMPRESSOR
Abstract
This variable speed scroll compressor includes a closed casing
including a low pressure volume and a high pressure volume, and an
electric motor arranged in the low pressure volume and including a
rotor and a stator, the rotor including permanent magnets, the
stator including a stator core provided with a plurality of
radially extending tooth portions and with a plurality of slots
formed between the radially extending tooth portions, and stator
windings each wound on the radially extending tooth portions. Each
stator winding is wound around a respective tooth portion and
includes winding portions extending respectively in the slots
formed on each side of the respective tooth portion.
Inventors: |
BONNEFOI; Patrice; (Saint
Didier Au Mont D'Or, FR) ; MELDENER; Gael; (Lyon,
FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DANFOSS COMMERCIAL COMPRESSORS |
Trevoux |
|
FR |
|
|
Family ID: |
47628200 |
Appl. No.: |
14/084152 |
Filed: |
November 19, 2013 |
Current U.S.
Class: |
417/365 |
Current CPC
Class: |
F04C 18/0215 20130101;
F04C 29/045 20130101; F04C 2240/40 20130101; F04C 18/0207 20130101;
F04C 29/0078 20130101 |
Class at
Publication: |
417/365 |
International
Class: |
F04C 29/04 20060101
F04C029/04; F04C 18/02 20060101 F04C018/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 19, 2012 |
FR |
12/60989 |
Claims
1. A variable speed scroll compressor comprising: a closed casing
comprising a low pressure volume and a high pressure volume, a
compression unit adapted for compressing refrigerant, an electric
motor arranged in the low pressure volume and comprising a rotor
and a stator. the rotor including permanent magnets, the stator
including a stator core provided with a plurality of radially
extending tooth portions and with a plurality of slots formed
between the radially extending tooth portions, and stator windings
wound on the radially extending tooth portions, each stator winding
being wound around a respective tooth portion, a drive shaft
adapted for driving the compression unit, the drive shaft being
rotatably coupled to the rotor, and a first axial abutment surface
provided on the rotor and a second axial abutment surface provided
on the drive shaft, a predetermined axial gap being provided
between the first and second axial abutment surfaces in order to
allow limited relative axial sliding movements between the rotor
and the drive shaft, wherein at least one slot formed between a
first and a second adjacent radially extending tooth portions
includes a first slot portion in which extends a winding portion of
a first stator winding wound around the first radially extending
tooth portion, a second slot portion in which extends a winding
portion of a second stator winding wound around the second radially
extending tooth portion, and a third slot portion arranged between
the first and second slot portions and defining a refrigerant flow
passage.
2. The variable speed scroll compressor according to claim 1,
wherein the ratio of the sum of the refrigerant flow passages
cross-sectional areas to the stator cross-sectional area is between
3 and 14%.
3. The variable speed scroll compressor according to claim 1,
wherein the variable speed scroll compressor is configured to force
at least a part of the refrigerant entering the refrigerant suction
inlet to pass through the refrigerant flow passages of the
slots.
4. The variable speed scroll compressor according to claim 1,
further comprising an intermediate jacket surrounding the stator,
the intermediate jacket delimiting an annular outer volume with the
closed casing and at least an inner chamber, which contains a first
winding head of the stator directed towards the high pressure
volume.
5. The variable speed scroll compressor according to claim 1,
further comprising a locking element adapted to rotatably couple
the drive shaft to the rotor.
6. The variable speed scroll compressor according to claim 5,
wherein an outer surface of the drive shaft has a first
longitudinal recess, and an inner surface of the rotor has a second
longitudinal recess, the first and second longitudinal recesses
being circumferentially aligned and the locking element extending
into the first and second longitudinal recesses.
7. The variable speed scroll compressor according to claim 5,
wherein the locking element is adapted to allow limited relative
angular sliding movements between the rotor and the drive shaft
8. The variable speed scroll compressor according to claim 1,
further comprising a positioning element secured on the drive shaft
the positioning element having an axial stop surface arranged to
slidably co-operate with an end portion of the rotor opposite to
the compression unit.
9. The variable speed scroll compressor according to claim 8,
wherein the positioning element is a positioning ring secured to
the drive shaft.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a variable speed scroll
compressor.
BACKGROUND OF THE INVENTION
[0002] As known, a scroll-type compressor may comprise: [0003] a
closed casing comprising a low pressure volume and a high pressure
volume, and [0004] a variable speed electric motor arranged in the
low pressure volume, the electric motor comprising a rotor and a
stator, the rotor including permanent magnets, the stator including
a stator core provided with a plurality of radially extending tooth
portions and with a plurality of slots formed between the radially
extending tooth portions, and stator windings wound on the radially
extending tooth portions.
[0005] In such a scroll-type compressor, the stator windings almost
completely fill out the slots provided in the stator core.
Therefore, in operation, the low temperature low pressure
refrigerant entering the low pressure volume flows essentially
through a small annular gap delimited between the rotor core and
the stator core.
[0006] As a result, the cooling of the stator windings and of the
permanent magnets provided in the rotor core could be insufficient.
This could lead to a demagnetization of the permanent magnets due
to excessive heating of the permanent magnets by the hot stator
windings. This issue is more critical at low rotational speed when
the refrigerant flow is low.
[0007] Further, due to the flow of refrigerant through the small
annular gap delimited between the rotor core and the stator core,
the pressure drop for the refrigerant is high, which reduces the
compressor efficiency especially at high rotational speed when the
refrigerant flow is high.
SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to provide an
improved variable speed scroll compressor which can overcome the
drawbacks encountered in conventional scroll compressors.
[0009] Another object of the present invention is to provide a
variable speed scroll compressor which is reliable and has an
enhanced efficiency.
[0010] According to the invention such a variable speed scroll
compressor comprises: [0011] a closed casing comprising a low
pressure volume and a high pressure volume, [0012] a compression
unit adapted for compressing refrigerant, [0013] an electric motor
arranged in the low pressure volume and comprising a rotor and a
stator, the rotor including permanent magnets, the stator including
a stator core provided with a plurality of radially extending tooth
portions and with a plurality of slots formed between the radially
extending tooth portions, and stator windings wound on the radially
extending tooth portions, each stator winding being wound around a
respective tooth portion, [0014] a drive shaft adapted for driving
the compression unit, the drive shaft being rotatably coupled to
the rotor, and [0015] a first axial abutment surface provided on
the rotor and a second axial abutment surface provided on the drive
shaft, a predetermined axial gap being provided between the first
and second axial abutment surfaces in order to allow limited
relative axial sliding movements between the rotor and the drive
shaft,
[0016] wherein at least one slot formed between a first and a
second adjacent radially extending tooth portions includes a first
slot portion in which extends a winding portion of a first stator
winding wound around the first radially extending tooth portion, a
second slot portion in which extends a winding portion of a second
stator winding wound around the second radially extending tooth
portion, and a third slot portion arranged between the first and
second slot portions and defining a refrigerant flow passage.
[0017] Such a winding of the stator windings on the tooth portions
of the stator core allows maintaining a large free flow section
within the stator slots for the flow of the refrigerant through
said stator slots. This leads on the one hand to reduce pressure
drop for the refrigerant, which enhances compressor efficiency, and
on the other hand to improve the cooling of the stator windings
even at low rotational speed of the motor.
[0018] Consequently, the stator and rotor cores, and especially the
permanent magnets are effectively protected against any degradation
whatever the operating conditions of the compressor according to
the invention.
[0019] According to an embodiment of the invention, each slot
formed between a first and a second adjacent radially extending
tooth portions includes a first slot portion in which extends a
winding portion of a first stator winding wound around the first
radially extending tooth portion, a second slot portion in which
extends a winding portion of a second stator winding wound around
the second radially extending tooth portion, and a third slot
portion arranged between the first and second slot portions and
defining a refrigerant flow passage.
[0020] According to an embodiment of the invention, the variable
speed scroll compressor further comprises a refrigerant suction
inlet opening into the low pressure volume.
[0021] According to an embodiment of the invention, the variable
speed scroll compressor is configured to force at least a part of
the refrigerant entering the refrigerant suction inlet to pass
through the refrigerant flow passages of the slots in order to cool
the stator windings and the permanent magnets.
[0022] According to an embodiment of the invention, the ratio of
the sum of the refrigerant flow passages cross-sectional areas to
the stator cross-sectional area is between 3 and 14%, preferably
between 5 and 10%, and for example between 6 and 8%. The stator
cross-sectional area does not comprise the central opening for
accommodating the rotor.
[0023] According to an embodiment of the invention, the electric
motor is a variable-speed electric motor.
[0024] The variable speed scroll compressor may further comprise an
intermediate jacket surrounding the stator, the intermediate jacket
delimiting an annular outer volume with the closed casing and at
least a first inner chamber which contains a first winding head of
the stator directed towards the high pressure volume.
[0025] According to an embodiment of the invention, the variable
speed scroll compressor may further comprise a securing member for
securing the stator core to the closed casing, the intermediate
jacket being formed by a cap covering an end portion of the stator
core directed towards the high pressure volume.
[0026] The variable speed scroll compressor may further comprise
conveying means for conveying at least some of the refrigerant
entering the refrigerant suction inlet into the inner chamber.
According to an embodiment of the invention, the conveying means
include an intake orifice provided in the cap and facing the
refrigerant suction inlet.
[0027] According to an embodiment of the invention, the electric
motor is entirely arranged in the intermediate jacket, the
intermediate jacket being mounted on a support frame separating the
low and high pressure volumes.
[0028] According to an embodiment of the invention, the variable
speed scroll compressor further comprises a centering member
secured to the closed casing and on which is secured an end portion
of the intermediate jacket opposite to the high pressure volume,
the centering member and the intermediate jacket delimiting a
second inner chamber which contains a second winding head of the
stator opposite to the first winding head, the centering member
being further provided with at least one refrigerant passage
aperture opening into the second inner chamber.
[0029] According to an embodiment of the invention, the rotor is
slide-fitted on the drive shaft in a slide-fit relationship
arranged to allow limited relative angular and/or axial sliding
movements between the rotor and the drive shaft. In other words,
the rotor is fitted on the drive shaft with an axial and/or angular
play (or clearance).
[0030] According to an embodiment of the invention, the centering
member is provided with a guide bearing arranged to guide an end
portion of the drive shaft opposite to the compression unit.
[0031] According to an embodiment of the invention, the variable
speed scroll compressor further comprises a locking element adapted
to rotatably couple the drive shaft to the rotor. For example, the
locking element can be made of non-magnetic material.
[0032] For example, an outer surface of the drive shaft has a first
longitudinal recess, and an inner surface of the rotor has a second
longitudinal recess, the first and second longitudinal recesses
being circumferentially aligned and the locking element extending
into the first and second longitudinal recesses. The locking
element may be adapted to allow limited relative angular sliding
movements between the rotor and the drive shaft.
[0033] According to an aspect of the invention, the locking element
is slide-fitted into at least one of the first and second
longitudinal recesses.
[0034] According to an aspect of the invention, the section
dimensions of the locking element and of the first and second
longitudinal recesses are adapted to allow limited relative axial
and/or angular sliding movements between the rotor and the drive
shaft.
[0035] According to an embodiment of the invention, the variable
speed scroll compressor further comprises a positioning element
secured on the drive shaft, the positioning element having an axial
stop surface arranged to slidably co-operate with an end portion of
the rotor opposite to the compression unit. The positioning element
may be a positioning ring secured to the drive shaft.
[0036] According to an embodiment of the invention, the positioning
element is heat shrink fitted to the drive shaft. For example, the
positioning element can be made of non-magnetic material.
[0037] According to an aspect of the invention, in use, the drive
shaft extends substantially vertically.
[0038] According to an embodiment of the invention, a lower end
portion of the rotor rests on the axial stop surface of the
positioning element.
[0039] These and other advantages will become apparent upon reading
the following description in view of the drawing attached hereto
representing, as non-limiting examples, two embodiments of the
variable speed scroll compressor according to the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] The following detailed description of embodiments of the
invention is better understood when read in conjunction with the
appended drawings being understood, however, that the invention is
not limited to the specific embodiments disclosed.
[0041] FIG. 1 is a longitudinal section view of a scroll-type
refrigeration compressor according to a first embodiment of the
invention.
[0042] FIG. 2 is an enlarged view of a detail of FIG. 1.
[0043] FIG. 3 is an enlarged view of a detail of FIG. 2.
[0044] FIG. 4 is an exploded perspective view of a detail of the
refrigeration compressor of FIG. 1.
[0045] FIG. 5 is a perspective view of the different elements shown
in FIG. 4.
[0046] FIG. 6 is a cross sectional view of the scroll-type
refrigeration compressor according to FIG. 1.
[0047] FIG. 7 is a top view of a stator core and a rotor core of
the scroll-type refrigeration compressor according to FIG. 1.
[0048] FIG. 8 is a longitudinal section view of a scroll-type
refrigeration compressor according to a second embodiment of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0049] FIG. 1 shows a scroll-type refrigeration compressor 2
occupying a vertical position. However, the refrigeration
compressor 2 according to the invention could occupy an inclined
position, or a horizontal position, without significant
modification to its structure.
[0050] The refrigeration compressor 2 shown in FIG. 1 comprises a
closed casing 3 defined by a shell 4 whose top and bottom ends are
respectively closed by a cap 5 and a base 6.
[0051] The refrigeration compressor 2 also comprises a support
frame 7 fixed in the closed casing 3, the closed casing 3 and the
support frame 7 defining a low pressure volume.
[0052] The refrigeration compressor 2 further comprises a scroll
compression unit 8 disposed above the support frame 7. The scroll
compression unit 8 has a fixed scroll member 9 and an orbiting
scroll member 11 interfitting with each other. In particular the
orbiting scroll member 11 is supported by and in slidable contact
with an upper face of the support frame 7, and the fixed scroll
member 11 is fixed in relation to the closed casing 3. The fixed
scroll member 11 could for example be fixed to the support frame
7.
[0053] As known, the fixed scroll member 9 has an end plate 12 and
a spiral wrap 13 projecting from the end plate 12 towards the
orbiting scroll member 11, and the orbiting scroll member 11 has an
end plate 14 and a spiral wrap 15 projecting from the end plate 14
towards the fixed scroll member 9. The spiral wrap 15 of the
orbiting scroll member 11 meshes with the spiral wrap 13 of the
fixed scroll member 9 to form a plurality of compression chambers
16 between them. The compression chambers 16 have a variable volume
which decreases from the outside towards the inside, when the
orbiting scroll member 11 is driven to orbit relative to the fixed
scroll member 9. The end plate 12 of the fixed scroll member 9
includes, in its central part, a discharge aperture 17 opening into
the central compression chamber 16 and leading to a high pressure
discharge chamber 18.
[0054] The refrigeration compressor 2 also includes a refrigerant
suction inlet 19 opening into the low pressure volume to achieve
the supply of refrigerant to the compressor, and a discharge outlet
20 which opens into the discharge chamber 18.
[0055] The refrigeration compressor 2 further comprises an electric
variable-speed motor disposed below the support frame 7, i.e. in
the low pressure volume. The electric motor has a rotor 21 and a
stator 22 disposed around the rotor 21.
[0056] As shown in FIG. 7, the rotor 21 includes a rotor stack or
rotor core 23 provided with an axial through passage 24, and
permanent magnets 25 inserted into longitudinal slots provided in
the rotor core 23. The permanent magnets 25 are for example
regularly arranged around the axial through passage 24.
[0057] As shown in FIGS. 6 and 7, the stator 22 includes a stator
stack or stator core 26, and stator windings 27 wound on the stator
core 26, The stator core 26 is provided on its inner periphery with
a plurality of radially extending tooth portions 28, and with a
plurality of longitudinal slots 29 formed between the radially
extending tooth portions 28. According to the invention, each
stator winding 27 is wound directly around a respective tooth
portion 28 and extends in the longitudinal slots 29 formed on each
side of said respective tooth portion 28. Each slot 29 includes a
first slot portion in which extends a winding portion of a first
adjacent stator winding 27, a second slot portion in which extends
a portion of a second adjacent stator winding 27, and a third slot
portion arranged between the first and second slot portions and
defining a refrigerant flow passage 30.
[0058] The stator core 26 may for example includes six tooth
portions 28 and six longitudinal slots 29, and the stator 22 may
therefore includes six stator windings 27.
[0059] Furthermore the refrigeration compressor 2 comprises a drive
shaft 31 adapted for driving the orbiting scroll member 11 in an
orbital movement. The drive shaft 31 extends into the axial through
passage 24 of the rotor 21 and is rotatably coupled to the rotor 21
so that the drive shaft 31 is driven to rotate by the rotor 21
about a rotational axis.
[0060] The drive shaft 31 comprises, at its top end, an eccentric
pin 32 which is off-centered from the center of the drive shaft 31,
and which is inserted in a connecting sleeve part 33 of the
orbiting scroll member 11 so as to cause the orbiting scroll member
11 to be driven in an orbital movement relative to a fixed scroll
member 9 when the electric motor is operated.
[0061] The bottom end of the drive shaft 31 drives an oil pump 34
which supplies oil from a sump defined by the closed casing 3 to a
lubrication passage 35 formed inside the central part of the drive
shaft 31.
[0062] The refrigeration compressor 2 further includes a
positioning ring 36 secured to the drive shaft 31. For example, the
positioning ring 36 is heat shrink fitted to the drive shaft 31.
The positioning ring 36 may be made of non-magnetic material.
[0063] The positioning ring 36 has an axial stop surface 37 on
which rests a lower end portion of the rotor 21, and more precisely
a radial abutment surface 38 provided on the lower end portion of
the rotor 21. Thus the positioning ring 36 is arranged to axially
position the rotor 21.
[0064] As shown in FIGS. 2 and 3, the refrigeration compressor 2
includes a first annular axial abutment surface 39 provided on the
rotor 21 and a second annular axial abutment surface 41 provided on
the drive shaft 31. As particularly shown in FIG. 3, a
predetermined axial gap may be provided between the first and
second axial abutment surfaces 39, 41 in order to allow limited
relative axial sliding movements between the rotor 21 and the drive
shaft 31. For example, the predetermined axial gap is between a few
micrometers and 1 mm.
[0065] Particularly, the first annular axial abutment surface 28 is
provided on the upper end face of the rotor 21, and the drive shaft
28 has a radial step delimiting the second annular axial abutment
surface 29. The first and second annular axial abutment surfaces
28, 29 are arranged to prevent the rotor 21 from axially moving
relative to the drive shaft 24 beyond a predetermined position
towards the compression unit 8.
[0066] The refrigeration compressor 2 further comprises a locking
pin 42 adapted to rotatably couple the drive shaft 31 to the rotor
21. For example the locking pin 42 is made of non-magnetic
material.
[0067] The locking pin 42 extends respectively into a first
longitudinal recess 43 provided on the outer surface of the drive
shaft 31 and into a second longitudinal recess 44 provided on the
inner surface of the rotor core 23, the first and second
longitudinal recesses 43, 44 being circumferentially aligned. The
section dimensions of the locking pin 42 and of the first and
second longitudinal recesses 43, 44 are adapted to allow limited
relative axial and angular sliding movements between the rotor 21
and the drive shaft 31. The locking pin 42 may be slightly larger
than the first longitudinal recesses 43 so that the locking pin 42
is press fitted into the first longitudinal recess 43, and the
locking pin 42 may be slide-fitted into the second longitudinal
recess 44. However, alternately the locking pin 42 may be
slide-fitted into the first and second longitudinal recesses 43,
44.
[0068] The second longitudinal recess 44 provided on the rotor 21
can extend along the entire length of the rotor core 23.
Advantageously, the first longitudinal recess 43 extends only along
a partial length of the drive shaft 31 and delimits an axial stop
surface 45 for the upper end of the locking pin 42. Furthermore the
axial stop surface 37 provided on the positioning ring 36 forms
also an axial stop for the lower end of the locking pin 42.
[0069] The refrigeration compressor 2 also includes an annular
fixing member 46 for fixing the stator 22 to the closed casing, and
a centering member 47 secured to the closed casing 3 and provided
with a guide bearing 40 arranged to guide the lower end portion of
the drive shaft 31.
[0070] The refrigeration compressor 2 further comprises an
intermediate jacket 48 surrounding the stator 22 and covering the
upper end of the electric motor. The intermediate jacket 48 and the
closed casing 3 delimit an annular outer volume 49 into which opens
the refrigerant suction inlet 19. The intermediate jacket 48
delimits, with the electric motor, an inner chamber 50 containing
the winding head 27a of the stator 22 oriented towards the scroll
compression unit 8. The winding head 27a is formed by the portions
of the stator windings 27 extending towards outside from the end
face 26a of the stator core 26 oriented towards the scroll
compression unit 8.
[0071] The intermediate jacket 48 is provided with an intake
orifice 51 opening into the proximal chamber 50 and facing the
refrigerant suction inlet 19 in order to allow admission of
refrigerant into the proximal chamber 49. Further, the support
frame 7 comprises one or several refrigerant passage apertures 52
opening into the low pressure volume and into the scroll
compression unit 8.
[0072] In operation, a first part of the refrigerant entering
through the refrigerant suction inlet 19 flows into the annular
outer volume 49, and then flows upwardly directly towards the
scroll compression unit 8 via the refrigerant passage apertures
52.
[0073] Further, a second part of the refrigerant entering the
refrigerant suction inlet 19 flows into the inner chamber 50
through the intake orifice 51 of the intermediate jacket 48, and
then flows downwardly towards the centering member 47 by passing
through the refrigerant flow passages 30 (shown in FIG. 6)
delimited by the stator core 26 and the stator windings 27. It
should be noted that a part of the refrigerant that has entered
into the inner chamber 50 may also flow downwardly towards the
centering member 47 through gaps 54 delimited between the stator
core 26 and the rotor core 23. The refrigerant passing through the
refrigerant flow passages 30 cools down the stator windings 27,
while the refrigerant passing through the gaps 54 cools down the
stator core 26 and the rotor core 23, which protects the stator
core, the rotor core and the permanent magnets of the latter
against damage.
[0074] Next, the refrigerant travels upwards through the low
pressure volume towards the scroll compression unit 8 and enters
the compression chambers 16 via the refrigerant passage apertures
52.
[0075] Then, the refrigerant entering the scroll compression unit 8
is compressed in the compression chambers 16 and escapes from the
centre of the fixed and orbiting scroll members 9, 11 through the
discharge aperture 17 leading to the discharge chamber 18, from
which the compressed refrigerant is discharged by the discharge
outlet 20.
[0076] FIG. 8 shows a scroll-type refrigeration compressor 2
according to a second embodiment of the invention which differs
from the one disclosed in FIGS. 1 to 7 essentially in that the
electric motor is entirely arranged in the intermediate jacket 48,
and in that the intermediate jacket 48 and the electric motor
define a proximal chamber 55a containing the winding head 27a of
the stator 22 oriented towards the scroll compression unit 8 and a
distal chamber 55b containing the winding head 27b of the stator 22
opposite to the first winding head 27a, the winding heads 27b being
formed by the portions of the stator windings 27 extending towards
outside from the end face 26b of the stator core 26 opposite to the
end face 26a.
[0077] According to the second embodiment, the upper end of the
intermediate jacket 48 is secured to the support frame 7 and the
lower end of the intermediate jacket 48 is secured to the centering
member 47, so that the intermediate jacket 48 serves to fix the
stator core 26. It should be noted that an annular connection
element 56 may be arranged between the intermediate jacket 48 and
the stator 22.
[0078] Further, according to the second embodiment, the centering
member 47 is further provided with at least one refrigerant passage
aperture 57 opening into the distal chamber 54b.
[0079] In operation, the refrigerant entering through the
refrigerant suction inlet 19 flows downwardly in the annular outer
volume 49 towards the centering member 47. Then, the refrigerant
flows through the refrigerant passage aperture 57 provided in the
centering member 47, and enters the distal chamber 55b. The
refrigerant that has entered into the distal chamber 55b flows
upwardly towards the scroll compression unit 8 via the refrigerant
flow passages 30 delimited by the stator core 26 and the stator
windings 27, the proximal chamber 55a and refrigerant passage
apertures (non shown in FIG. 8) provided in the support frame 7. It
should be noted that a part of the refrigerant that has entered
into the distal chamber 55b may flow upwardly towards the scroll
compression unit 8 through gaps (not shown in FIG. 8) delimited by
the intermediate jacket 48 and the outer periphery of the stator
22.
[0080] Next, the refrigerant entering the scroll compression unit 8
is compressed in the compression chambers 16 and escapes from the
centre of the fixed and orbiting scroll members 9, 11 through the
discharge aperture 17 leading to the discharge chamber 18, from
which the compressed refrigerant is discharged by the discharge
outlet 20.
[0081] Of course, the invention is not restricted to the
embodiments described above by way of non-limiting examples, but on
the contrary it encompasses all embodiments thereof.
* * * * *