U.S. patent application number 09/737539 was filed with the patent office on 2001-06-21 for scroll compressor.
Invention is credited to Fujii, Toshiro, Murakami, Kazuo, Nakane, Yoshiyuki, Tarao, Susumu.
Application Number | 20010004445 09/737539 |
Document ID | / |
Family ID | 18449492 |
Filed Date | 2001-06-21 |
United States Patent
Application |
20010004445 |
Kind Code |
A1 |
Fujii, Toshiro ; et
al. |
June 21, 2001 |
Scroll compressor
Abstract
Scroll compressors are taught that include an outer peripheral
portion (23) of a movable scroll member (20) disposed opposite of
an end face (13) of a stationary scroll member (10). At least one
end portion (20, 23) has a shape that prevents contact when the
movable scroll member (20) bends or deforms under high pressure.
The contact avoiding shape or structure may be, for example, a
tapered portion, a recessed portion or a step shaped portion.
Inventors: |
Fujii, Toshiro; (Kariya-shi,
JP) ; Murakami, Kazuo; (Kariya-shi, JP) ;
Nakane, Yoshiyuki; (Kariya-shi, JP) ; Tarao,
Susumu; (Kariya-shi, JP) |
Correspondence
Address: |
MORGAN AND FINNEGAN, L.L.P.
345 Park Avenue
New York
NY
10154
US
|
Family ID: |
18449492 |
Appl. No.: |
09/737539 |
Filed: |
December 15, 2000 |
Current U.S.
Class: |
418/1 ;
418/55.2 |
Current CPC
Class: |
F04C 18/0253
20130101 |
Class at
Publication: |
418/1 ;
418/55.2 |
International
Class: |
F04C 018/00; F04C
018/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 15, 1999 |
JP |
11-356531 |
Claims
What is claimed is:
1. A scroll compressor comprising: a stationary scroll member
having a stationary base plate and a stationary volute wall
extending from the stationary base plate, wherein the stationary
base plate includes an end portion; a movable scroll member having
a movable base plate and a movable volute wall extending from the
movable base plate, wherein the movable base plate includes an end
portion and engages the stationary scroll member to define a
compression chamber between the movable scroll member and the
stationary scroll member, wherein fluid is pressurized in the
compression chamber as the movable scroll member orbits with
respect to the stationary scroll member, wherein at least one of
the end portions of the stationary base plate and the movable base
plate comprises a contact avoiding structure so that the end
portion of the stationary base plate does not contact the end
portion of the movable base plate when the compression chamber is
under high pressure.
2. A scroll compressor according to claim 1, wherein the end
portion of the stationary base plate includes an end face disposed
at the outer periphery of the stationary base plate, and the end
portion of the movable base plate includes an outer peripheral
portion at the end face of the movable base plate.
3. A scroll compressor according to claim 2, wherein the contact
avoiding structure is a tapered shape formed at the outer
peripheral portion of the movable base plate and is inclined toward
an outer peripheral direction.
4. A scroll compressor according to claim 2, wherein the contact
avoiding structure is a recess shape formed in the end face of the
stationary base plate.
5. A scroll compressor according to claim 2, wherein the contact
avoiding structure is a step shape formed in the outer peripheral
portion of the movable base palate.
6. A scroll compressor according to claim 1, wherein the fluid is
carbon dioxide.
7. An air conditioning system for a vehicle comprising at least a
cooling circuit and a scroll compressor according to claim 1, the
scroll compressor compressing fluid for operating the air
conditioning system.
8. A scroll compressor comprising: a stationary scroll member
having a stationary base plate and a stationary volute wall
extending from the stationary base plate, wherein the stationary
base plate includes an end portion; a movable scroll member having
a movable base plate and a movable volute wall extending from the
movable base plate, wherein the movable base plate includes an end
portion and engages the stationary scroll member to define a
compression chamber between the movable scroll member and the
stationary scroll member, wherein fluid is pressurized in the
compression chamber as the movable scroll member orbits with
respect to the stationary scroll member, wherein the end portions
of the stationary scroll member and the movable scroll member are
constructed and arranged to avoid contact when the movable scroll
member deforms in response to a high pressure condition in the
compression chamber.
9. A scroll compressor according to claim 8, wherein the end
portion of the stationary scroll member includes an end face
disposed at the outer periphery of the stationary base plate, and
the end portion of the movable scroll member includes an outer
peripheral portion at the end face of the movable base plate.
10. A scroll compressor according to claim 9, wherein an outer
peripheral portion of the movable base plate at a side facing the
stationary scroll member has a tapered shape and is inclined toward
an outer peripheral direction.
11. A scroll compressor according to claim 9, wherein the end
portion of the stationary base plate comprises an end face having a
recessed shape at a portion that would contact an outer peripheral
portion of the movable base plate when the movable scroll member
deforms under high pressure in the absence of the recessed
shape.
12. A scroll compressor according to claim 9, wherein an outer
peripheral portion of the movable base plate has a step shape at a
portion that would contact the end face of the stationary base
plate when the movable scroll member deforms under high pressure in
the absence of the step shape.
13. A scroll compressor according to claim 8, wherein the fluid is
carbon dioxide.
14. A method for compressing a fluid in the scroll compressor of
claim 1, comprising: drawing a fluid into the compression chamber,
compressing the fluid and discharging a highly pressurized fluid,
wherein the end portions of the scroll members do not contact when
the fluid is pressurized and the movable scroll member deforms
under pressure.
15. A method as in claim 14, wherein the contact avoiding structure
is a tapered shape formed in the outer peripheral portion of the
movable base plate and is inclined toward an outer peripheral
direction.
16. A method as in claim 14, wherein the contact avoiding structure
is a recess shape formed in the end face of the stationary base
plate.
17. A method as in claim 14, wherein the contact avoiding structure
is a step shape formed in the outer peripheral portion of the
movable base plate.
18. A method as in claim 13, wherein the fluid is carbon dioxide.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present teachings relate to scroll compressors for
compressing fluids, such as a refrigerant, and such scroll
compressors may be utilized, for example, in air conditioning
systems and refrigerating systems.
[0003] 2. Description of the Related Art
[0004] Japanese Laid-Open Patent Publication No. 5-312156 discloses
a known scroll compressor. As shown in FIG. 6, the known scroll
compressor includes a stationary scroll member 110 and a movable
scroll member 120. The movable scroll member 120 moves in an
orbital motion about the stationary scroll member 110. The
stationary scroll member 110 has a volute wall 112 extending from a
base plate 111, and the movable scroll member 120 has a volute wall
122 extending from a base plate 121. The scroll members 110, 120
are arranged in such a manner that the respective volute walls 112,
122 are proximally disposed with respect to each other and
co-operate to compress a fluid. A plurality of compression chambers
114 are defined between the stationary scroll member 110 and the
movable scroll member 120. As the movable scroll member 120 orbits
with respect to the stationary scroll member 110, fluid is drawn
into the compression chamber 114 and compressed as the compression
chambers 114 shift toward the center of the scroll members 110 and
120, thereby reducing the space within the compression chambers
114.
[0005] In the known scroll compressor, a high pressure is generated
in the compression chambers 114 as the fluid is compressed. The
high pressure is exerted against the stationary scroll member 110
and the movable scroll member 120. The pressure in the compression
chamber 114 becomes higher as the compression chamber 114 shifts
from the outer periphery toward the center of the scroll members.
As a result, as shown in exaggerated form in FIG. 6, the movable
scroll member 120 will deform so that its central section bulges
towards to the right, as shown in FIG. 6. Because the end face of
the outer peripheral portion 113 of the movable scroll member 120
and the end face 123 of the stationary scroll member 110 will come
into contact due to the deformation of the movable scroll member
120, friction will be generated between the movable scroll member
120 and the stationary scroll member 110. Therefore, power loss and
seizing may be caused by this friction.
SUMMARY OF THE INVENTION
[0006] It is accordingly an object of the present teachings is to
provide an improved scroll compressor.
[0007] Because the movable scroll member of the known scroll
compressor will deform as the pressure of the fluid in the
compression chamber is increased, the known scroll compressor is
prone to power loss and seizing when the compression chamber is
under high pressure. Consequently, such problems are preferably
overcome by the present teachings.
[0008] In one aspect of the present teachings, a scroll compressor
may include a stationary scroll member, a movable scroll member and
a plurality of compression chambers defined between the two scroll
members. As the pressure in the compression chambers increases, the
movable scroll member will deform. Therefore, end portions of the
base plates of the scroll members are arranged and constructed to
avoid contact when the movable scroll member deforms. Thus, by
designing the end portions according to the present teachings,
power loss and seizures can be avoided, thereby improving
compression efficiency.
[0009] The end portions preferably comprise a contact avoiding
structure, in which at least one of the end portions of the base
plates of the scroll members has a shape that will avoid contact
with the end portion of the other scroll member when the movable
scroll member deforms. Although the contact avoiding structure may
be relatively simple, it is effective to prevent contact between
the end portion of the stationary scroll member and the end portion
of the movable scroll member during operation under high
pressure.
[0010] Such scroll compressors may preferably compress carbon
dioxide (CO.sub.2) as a refrigerant. The pressure difference of
C0.sub.2 between its lower pressure and higher pressure may be, for
example, more than 5 MPa (megapascal). That is, when the carbon
dioxide is compressed, the compression chamber 114 will be
subjected to a higher pressure than usual, and the movable scroll
member 120 is likely to deform. However, even if the movable scroll
member deforms, scroll compressors according to the present
teachings can effectively pre vent the movable scroll member 120
from contacting the stationary scroll member 110.
[0011] For example, the scroll compressors may preferably be
utilized in air conditioning systems and in refrigerating systems.
More preferably, the scroll compressors may be utilized in
automobile air conditioning systems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 schematically shows the internal cross section of a
scroll compressor according to a first representative embodiment of
the present teachings.
[0013] FIG. 2 is a partially enlarged view showing a periphery of
an end portion of the movable scroll member of FIG. 1, and
illustrating the relative positions between the stationary scroll
member and the movable scroll member.
[0014] FIG. 3 is a partially enlarged view showing a periphery of
an end portion of the movable scroll member of FIG. 1, and
illustrating the relative positions between the stationary scroll
member and the movable scroll member.
[0015] FIG. 4 is a partially enlarged view showing a periphery of
an end portion of the movable scroll member according to a second
representative embodiment, and illustrating the relative positions
between the stationary scroll member and the movable scroll
member.
[0016] FIG. 5 is a partially enlarged view showing a movable base
plate member that includes a step shape in its outer peripheral
portion.
[0017] FIG. 6 is a cross-sectional view schematically showing a
known scroll compressor.
DETAILED DESCRIPTION OF THE INVENTION
[0018] Scroll compressors are taught that may include a stationary
scroll member comprising a base plate having an end surface. A
movable scroll member comprising a base plate having an outer
peripheral portion may be disposed in an opposing relationship to
the stationary scroll member. A plurality of compression chambers
may be defined between the stationary scroll member and the movable
scroll member. The compression chambers are formed to compress a
fluid, such as a gas. Preferably, either one or both end faces of
the stationary scroll member and/or the outer peripheral portion of
moveable scroll member have a contact avoiding structure. In known
scroll compressors, when the movable scroll member deforms under
high pressure, which is caused by the compression of the fluid, the
periphery of the movable scroll member and the end face of the
stationary scroll member will contact each other. However,
according to the present teachings, the end face of the stationary
scroll member will not contact the periphery of the movable scroll
member when the compression chamber is under high pressure. That
is, the end face of the stationary scroll member and the periphery
of the moveable scroll member are preferably constructed and
arranged to avoid contact when the moveable scroll member deforms
in response to a high pressure condition in the compression
chamber.
[0019] For example, the contact avoiding structure may be a tapered
shape formed in the end face of the stationary scroll member and
the tapered shape may be inclined toward the outer peripheral
direction. Alternatively, the contact avoiding structure may be a
recess shape formed in the periphery of the movable scroll member.
Further, the contact avoiding structure may be a step shape formed
in the end face of the stationary scroll member. Naturally, various
other structures for avoiding contact between the periphery of the
movable scroll member and the end face of the stationary scroll
member may be utilized according to the present teachings.
[0020] Preferably, such a scroll compressor may be utilized to
compress carbon dioxide and may be utilized, for example, in an
automobile air conditioning system.
[0021] Methods for compressing a fluid in such scroll compressors
may include drawing a fluid into the compression chamber,
compressing the fluid and discharging a highly pressurized fluid.
Preferably, the end portions of the scroll members do not contact
when the fluid is pressurized and the movable scroll member deforms
under pressure.
[0022] Further representative examples of the present teachings
will now be described in further detail with reference to the
attached drawings. This detailed description is merely intended to
teach a person of skill in the art further details for practicing
preferred aspects of the present teachings and is not intended to
limit the scope of the invention. Only the claims define the scope
of the claimed invention. Therefore, combinations of features and
aspects disclosed in the following detail description may not be
necessary to practice the invention in the broadest sense, and are
instead taught merely to particularly describe some representative
examples of the invention. Moreover, various features of the
representative examples may be combined in ways that are not
specifically enumerated in order to provide additional useful
embodiments of the present teachings.
[0023] First Representative Embodiment
[0024] A scroll compressor according to a first embodiment of the
present teachings will be described with reference to FIGS. 1-3.
This scroll compressor may be used as a refrigerating compressor in
an air conditioner or a refrigerating machine, and preferably
compresses a refrigerant gas before discharging the compressed
refrigerant gas. For example, the scroll compressor may be used in
an air conditioner for vehicles.
[0025] As shown in FIG. 1, the scroll compressor 1 may includes a
scroll mechanism section 2 disposed within a hermetically enclosed
casing, and a drive mechanism section (not shown) for driving the
scroll mechanism section 2. The scroll mechanism section 2 may
include a stationary scroll member 10, a movable scroll member 20,
a supporting member 24 for orbitably supporting the movable scroll
member 20, and other structures known in the art. The stationary
scroll member 10 may have a spiral-shaped stationary volute wall 12
(i.e. an involute shape) extending from one surface of a stationary
base plate 11 in the form of circular plate. The movable scroll
member 20 may also have a spiral-shaped movable volute wall 22
(i.e. an involute shape) extending from one surface of a stationary
base plate 21 in the form of circular plate. The volute walls 12,
22 of the respective scroll members are engaged with each other. At
the ends of the volute walls 12, 22, respective chip seals 12a, 22a
are provided, which chip seals 12a, 22a preferably seal the volute
walls 12, 22 during operation.
[0026] The movable scroll member 20 may be supported by the
supporting member 24, and may be coupled to a drive shaft 31 of the
drive mechanism section through a crank mechanism 30. A crankshaft
30a of the crank mechanism 30 is provided at position Q, which is
eccentric from an axis P of the drive shaft 31. Due to the
eccentricity of the crank shaft 30a, the movable volute wall 22 of
the movable scroll member 20 is brought into contact with the
stationary volute wall 12 of the stationary scroll member 10 at a
plurality of portions of the respective wall surfaces at an inner
peripheral side and outer peripheral side. In the compression
chamber 14 defined by the volute walls 12, 22, a refrigerant, for
example, carbon dioxide (CO.sub.2) may be compressed. The drive
shaft 31 can rotate about the axis P, and is preferably coupled to
a rotation driving source (not shown).
[0027] The refrigerant in a low pressure section 14a of the
compression chamber 14 is drawn in the direction toward the center
of the movable scroll member 20 while the refrigerant is
increasingly compressed in conjunction with the orbital movement of
the movable scroll member 20, so as to form a high pressure section
14b. In the high pressure section 14b, the refrigerant is highly
pressurized. The highly pressurized gas is then allowed to flow
into a discharge chamber 16 via a discharge port 15 and a discharge
valve mechanism 17 (i.e. a check valve). The discharge port 15 and
discharge valve mechanism 17 open at a predetermined pressure and
are disposed in the central area of the base plate 11 of the
stationary scroll member 10. The compressed gas then is discharged
to the outside of the compressor (e.g., a refrigerating
circuit).
[0028] As shown in exaggerated form in FIG. 2, an outer peripheral
portion 23 of the base plate 21 of the movable scroll member 20 is
disposed in an opposing relationship with respect to an end face 13
of the base plate 11 of the stationary scroll member 10.
Preferably, the opposing face of the peripheral portion 23 has a
tapered or chamfered shape that is inclined toward an outer
peripheral direction at the whole circumference. The distance d1
between the opposing face of the outer peripheral portion 23 of the
movable scroll member 20 and the end face 13 of the stationary
scroll member 10 is preferably larger than the distance d1' between
an end face of a known movable scroll member (shown by an
alternating long and two short dashed line 23a,) and the end face
13 of a stationary scroll member 10. The structure of the outer
peripheral portion 23 of the movable scroll member 20 corresponds
to a representative contact avoiding structure of the present
teachings.
[0029] A representative method for compressing a refrigerant using
the scroll compressor 1 will be described with reference to FIGS. 1
to 3. When the drive shaft 31 is rotated by the driving source, the
crankshaft 30a rotates about the axle center P, and the movable
scroll member 20 orbits around the stationary scroll 10. The
refrigerant is drawn into the compression chamber 14 located at the
outer periphery, and is compressed as the contacting portions of
the volute walls 12, 22, shift toward the central direction and the
space of the compressor chamber 14 is reduced, due to the orbital
movement of the movable scroll member 20. As the space of the
compression chamber 14 is reduced, the pressure in the compression
chamber 14 is gradually increased, and the highly pressurized
refrigerant is discharged from the discharge port 15.
[0030] Naturally, the pressure of the highly pressurized
refrigerant is exerted against the base plate 21 of the movable
scroll member 20 from within the compression chamber 14. The
highest pressure is exerted against the central portion of the base
plate 21. As a result, as shown in FIG. 2, the center of the base
plate 21 of the movable scroll member 20 receives a pressure in the
direction shown by an arrow 40 in FIG. 2. Thus, the base plate 21
deforms or bends in response to the pressure as the central portion
shifts towards the direction shown by the arrow 40. As shown in
FIG. 3, the end portion 23 of the movable scroll member 20 is
deformed from the resting position (as shown by the alternating
long and two short dashed line 21a) to the position closer to the
end face 13 of the stationary scroll member 10. That is, when the
movable scroll member 20 receives high pressure, its center portion
bends away from the stationary scroll member 10. However, because
the portion around the outer peripheral portion 23 of the base
plate 21 is restricted by the supporting member 24, the peripheral
portion 23 projects toward the stationary scroll member 10 from the
supporting member 24 as a base point. At this time, if the distance
d2 that the peripheral portion 23 shifts is less than the distance
d1, the peripheral portion 23 of the movable scroll member 20 does
not contact the end face 13 of the stationary scroll member 10.
Thus, the peripheral portion 23 of the movable scroll member 20
preferably has a shape that prevents contacts with the end face 13
of the stationary scroll member 10, even if the pressure in the
compression chamber is increased. In this embodiment, the
peripheral portion 23 may have a tapered shape, which provides a
contact avoiding structure, and contact of the peripheral portion
23 of the movable scroll member 20 and the end face 13 of the
stationary scroll member 10 can be avoided.
[0031] In the scroll compressor according to the first embodiment,
when the movable scroll member 20 is deformed with respect to the
stationary scroll member 10, no friction is generated between the
peripheral portion 23 of the movable scroll member 20 and the end
face 13 of the stationary scroll 10. As a result, power loss and
seizing can be prevented or substantially reduced. This structure
is advantageous over known structures for avoiding seizure, because
the contact avoiding structure of the present teachings is easier
to construct than, for example, increasing the thickness of the
scroll wall of the movable scroll member 20 in order to make the
scroll wall more rigid.
[0032] Second Representative Embodiment
[0033] A structure of a scroll compressor according to a second
embodiment will be described with reference to FIG. 4. Elements
that are the same as elements shown in FIG. 2 are identified by the
same reference numerals. Because the scroll compressor according to
the second representative embodiment is similar to the first
representative embodiment, only the differences between the two
embodiments will be described.
[0034] As shown in FIG. 4, an outer peripheral portion 23 of a
movable scroll member 20 opposes an end face 13 of a stationary
scroll member 10. As shown by the alternating long and two short
dashed line 21a, the end face of the peripheral portion 23 is
substantially flat. On the other hand, the end face 13 of the
stationary scroll member 10 has a recessed shape. That is, in this
embodiment, the end face 13 of the stationary scroll member 10 has
an arc-shaped depression (for example, at a distance d4 from the
peripheral portion 23 of the movable scroll member 20). For
comparison, the alternating long and two short dashed line 13a
shows the shape used in known scroll compressors. Thus, the end
face 13 of the stationary scroll member 10 of this embodiment also
provides a contact avoiding structure of the present teachings.
[0035] Similar to the first representative embodiment, the high
pressure refrigerant within the compression chamber 14 presses
against the base plate 21 of the movable scroll member 20. As a
result, the peripheral portion 23 of the movable scroll member 20
is shifted from the resting position, as shown by the alternating
long and two short dashed line 21a, to the position closer to the
end face 13 of the stationary scroll member 10. At this time, if
the distance d3 that the end portion 23 shifts is less than the
distance d4, the peripheral portion 23 of the movable scroll member
20 will not contact the end face 13 of the stationary scroll member
10. Thus, the end face 13 of the stationary scroll member 10
preferably has a shape that avoids contact with the peripheral
portion 23 of the movable scroll member 20, even if the pressure in
the compression chamber is increased. In this embodiment, the
contact avoiding structure is a recess or depression, which
generally prevents the end face 13 of the stationary scroll member
10 from contacting the peripheral portion 23 of the movable scroll
member 20. Therefore, the scroll compressor of the second
representative embodiment can also realize the advantageous effects
noted with respect to the first representative embodiment.
[0036] Naturally, the present teachings are not limited to the
above-described embodiments and various applications and
modifications thereof may be utilized. In particular, the shapes
and positions of the contact avoiding structure are not limited to
the above described embodiments and may be modified without
departing from the spirit of the invention. For example, as shown
in FIG. 5, the peripheral portion 23 of the movable scroll member
20 may be step shaped at the position that would normally contact
the end face 13 of the stationary scroll member 10 when the movable
scroll member 20 deforms. Moreover, both the shapes of the
peripheral portion 23 of the movable scroll member 20 and the end
face 13 of the stationary scroll member 10 may be altered from
known shapes, in order to provide a contact avoiding structure.
Further, although the preferred embodiments are utilized to
compress a gas, the present teachings may naturally be utilized to
construct compressors for other applications, such as liquids.
* * * * *