U.S. patent application number 14/076693 was filed with the patent office on 2014-05-15 for scroll 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 Kazuo MURAKAMI, Ken SUITOU, Kosaku TOZAWA.
Application Number | 20140134033 14/076693 |
Document ID | / |
Family ID | 49578147 |
Filed Date | 2014-05-15 |
United States Patent
Application |
20140134033 |
Kind Code |
A1 |
TOZAWA; Kosaku ; et
al. |
May 15, 2014 |
SCROLL COMPRESSOR
Abstract
A scroll compressor includes a rotation shaft, a fixed scroll, a
movable scroll, a compression chamber, a shaft support, a housing,
a movable member arranged in the shaft support, and a rotation
restriction mechanism configured to restrict rotation of the
movable scroll. The rotation restriction mechanism includes pins,
recesses into which the respective pins are loosely fitted, and the
movable member. The movable member includes the pins or the
recesses. A switching mechanism is configured to switch the movable
member between a state in which movement of the movable member in a
radial direction of the rotation shaft is restricted and a state in
which the restriction is canceled and the movable member can move
freely, which changes a movable range of the movable member in the
radial direction so that an orbital radius of the movable scroll is
changed.
Inventors: |
TOZAWA; Kosaku; (Kariya-shi,
JP) ; SUITOU; Ken; (Kariya-shi, JP) ;
MURAKAMI; Kazuo; (Kariya-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kabushiki Kaisha Toyota Jidoshokki |
Kariya-shi |
|
JP |
|
|
Assignee: |
Kabushiki Kaisha Toyota
Jidoshokki
Kariya-shi
JP
|
Family ID: |
49578147 |
Appl. No.: |
14/076693 |
Filed: |
November 11, 2013 |
Current U.S.
Class: |
418/55.3 ;
418/55.1 |
Current CPC
Class: |
F01C 17/06 20130101;
F04C 28/08 20130101; F04C 18/0215 20130101; F04C 27/001 20130101;
F04C 28/22 20130101; F04C 18/0261 20130101; F04C 2270/13
20130101 |
Class at
Publication: |
418/55.3 ;
418/55.1 |
International
Class: |
F04C 28/22 20060101
F04C028/22; F04C 18/02 20060101 F04C018/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 13, 2012 |
JP |
2012-249186 |
Claims
1. A scroll compressor comprising: a rotation shaft; a fixed scroll
including a fixed spiral wall; a movable scroll including a movable
spiral wall engaged with the fixed spiral wall, wherein the movable
scroll orbits when the rotation shaft is rotated; a compression
chamber defined between the fixed spiral wall and the movable
spiral wall, wherein the compression chamber has a volume that is
decreased when the movable scroll orbits, and refrigerant is
compressed in the compression chamber when the volume is decreased;
a shaft support that supports the rotation shaft, wherein the shaft
support and the fixed scroll are arranged at opposite sides of the
movable scroll; a housing that accommodates the rotation shaft, the
fixed scroll, the movable scroll, and the shaft support; a movable
member arranged in the shaft support; a rotation restriction
mechanism configured to restrict rotation of the movable scroll,
wherein the rotation restriction mechanism includes a plurality of
pins, a plurality of recesses into which the respective pins are
loosely fitted, and the movable member, and wherein the movable
member includes one of the plurality of pins and the plurality of
recesses; and a switching mechanism configured to switch the
movable member between a state in which movement of the movable
member in a radial direction of the rotation shaft is restricted
and a state in which the restriction is canceled and the movable
member can move freely, which changes a movable range of the
movable member in the radial direction of the rotation shaft so
that an orbital radius of the movable scroll is changed.
2. The scroll compressor according to claim 1, wherein the
switching mechanism includes a valve chamber, which is arranged in
the shaft support, and a valve body, which is accommodated in the
valve chamber, and the valve body presses the movable member toward
the movable scroll.
3. The scroll compressor according to claim 2, wherein the valve
chamber includes a primary void and a secondary void, the primary
void is located between the secondary void and the movable scroll,
and the switching mechanism includes a switching valve configured
to switch between a state in which the secondary void is in
communication with a low pressure region, the pressure of which is
lower than that of the primary void, and a state in which the
secondary void is in communication with a high pressure region, the
pressure of which is higher than that of the primary void.
4. The scroll compressor according to claim 3, further comprising a
back pressure region located between the movable scroll and the
movable member and configured to apply force to the movable scroll
so that the movable scroll is pressed toward the fixed scroll,
wherein the movable member includes a communication passage that
communicates the back pressure region and the primary void.
5. The scroll compressor according to claim 3, wherein the valve
chamber is one of a plurality of valve chambers that are arranged
in the shaft support in intervals in a circumferential direction of
the rotation shaft, and the switching mechanism includes a passage
that extends in the shaft support from the switching valve to the
valve chambers.
6. The scroll compressor according to claim 2, wherein the movable
member includes a fitting recess to which the valve body can be
fitted.
7. The scroll compressor according to claim 2, further comprising a
seat member fixed to the housing and arranged between the movable
scroll and the movable member, wherein the seat member receives the
movable member that is pressed toward the movable scroll by the
valve body.
8. The scroll compressor according to claim 1, wherein the
switching mechanism includes a primary void and a secondary void
arranged in the shaft support, wherein the primary void is located
between the movable scroll and the secondary void, a conical recess
arranged in the shaft support, a conical projection that is
arranged in the movable member and movable toward and away from the
conical recess, and a switching valve that switches between a state
in which the secondary void is in communication with a low pressure
region, the pressure of which is lower than that of the primary
void, and a state in which the secondary void is in communication
with a high pressure region, the pressure of which is higher than
that of the primary void.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a scroll compressor.
[0002] Generally, a scroll compressor includes a fixed scroll,
which is fixed to a housing, and a movable scroll, which orbits
with respect to the fixed scroll. The fixed scroll includes a fixed
base plate and a fixed spiral wall projecting from the fixed base
plate. The movable scroll includes a movable base plate and a
movable spiral wall projecting from the movable base plate. The
fixed spiral wall and the movable spiral wall are engaged with each
other to define a compression chamber. The orbital movement of the
movable scroll decreases the volume of the compression chamber and
compresses refrigerant. Japanese Laid-Open Patent Publication No.
2010-14108 describes an example of such a scroll compressor.
[0003] In the scroll compressor, a large centrifugal force acts on
the movable scroll especially when the rotation shaft rotates at a
high speed. This increases the noise generated when the movable
spiral wall comes into contact with the fixed spiral wall. When the
movable spiral wall is spaced apart from the fixed spiral wall to
avoid contact between the spiral walls, leakage of the refrigerant
from the compression chamber increases when the rotation shaft
rotates at a low speed. This lowers the compression
performance.
SUMMARY OF THE INVENTION
[0004] It is an object of the present disclosure to provide a
scroll compressor that can reduce noise caused by contact between
the fixed spiral wall and the movable spiral wall when the rotation
shaft rotates at a high speed and reduce leakage of refrigerant
from the compression chamber when the rotation shaft rotates at a
low speed.
[0005] To achieve the above object, one aspect of the present
invention is a scroll compressor that includes a rotation shaft, a
fixed scroll including a fixed spiral wall, and a movable scroll
including a movable spiral wall engaged with the fixed spiral wall.
The movable scroll orbits when the rotation shaft is rotated. A
compression chamber is defined between the fixed spiral wall and
the movable spiral wall. The compression chamber has a volume that
is decreased when the movable scroll orbits, and refrigerant is
compressed in the compression chamber when the volume is decreased.
A shaft support supports the rotation shaft. The shaft support and
the fixed scroll are arranged at opposite sides of the movable
scroll. A housing accommodates the rotation shaft, the fixed
scroll, the movable scroll, and the shaft support. A movable member
is arranged in the shaft support. A rotation restriction mechanism
is configured to restrict rotation of the movable scroll. The
rotation restriction mechanism includes a plurality of pins, a
plurality of recesses into which the respective pins are loosely
fitted, and the movable member. The movable member includes one of
the plurality of pins and the plurality of recesses. A switching
mechanism is configured to switch the movable member between a
state in which movement of the movable member in a radial direction
of the rotation shaft is restricted and a state in which the
restriction is canceled and the movable member can move freely,
which changes a movable range of the movable member in the radial
direction of the rotation shaft so that an orbital radius of the
movable scroll is changed.
[0006] Other aspects and advantages of the present 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
[0007] 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:
[0008] FIG. 1 is a cross-sectional view showing a scroll compressor
of a first embodiment;
[0009] FIG. 2 is an enlarged cross-sectional view showing a
rotation restriction mechanism of the scroll compressor of FIG.
1;
[0010] FIG. 3 is a cross-sectional view showing the scroll
compressor of FIG. 1;
[0011] FIG. 4 is an enlarged cross-sectional view showing a
rotation restriction mechanism of the first embodiment;
[0012] FIG. 5 is an enlarged cross-sectional view showing the
rotation restriction mechanism of the second embodiment; and
[0013] FIG. 6 is an enlarged cross-sectional view showing the
rotation restriction mechanism of a second embodiment.
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
[0014] Referring to FIGS. 1 to 4, a first embodiment of a scroll
compressor (hereinafter referred to as the compressor) will now be
described. The compressor is installed in a vehicle and used with a
vehicle air-conditioning device.
[0015] As shown in FIG. 1, the compressor 10 includes a housing 11
made of metal (aluminum in the present embodiment). The housing 11
includes a cylindrical motor housing member 12 and a cylindrical
discharge housing member 13. The motor housing member 12 includes a
closed end and an open end 121h (left end as viewed in FIG. 1). The
discharge housing member 13, which has a closed end, is connected
to the open end 121h of the motor housing member 12. The motor
housing member 12 accommodates a compression unit P, which
compresses refrigerant, and an electric motor M, which drives the
compression unit P.
[0016] The motor housing member 12 includes an end wall 12a and a
cylindrical shaft support portion 121a projecting from the central
section of the end wall 12a. A shaft support 21 is fixed in the
motor housing member 12 near the open end 121h. An insertion hole
21a extends through a central section of the shaft support 21. The
motor housing member 12 also accommodates a rotation shaft 20. The
rotation shaft 20 includes two ends. One end, which faces toward
the open end 121h of the motor housing member 12, is located in the
insertion hole 21a of the shaft support 21 and supported by a
bearing B1 to be rotatable relative to the shaft support 21. The
other end of the rotation shaft 20 faces toward the end wall 12a of
the motor housing member 12 and is supported by a bearing B2 to be
rotatable relative to the shaft support portion 121a. The bearings
B1 and B2 are plain bearings.
[0017] The motor housing member 12 includes a motor chamber 121
extending between the shaft support 21 and the end wall 12a. The
motor chamber 121 accommodates the electric motor M that includes a
rotor 16, which rotates integrally with the rotation shaft 20, and
a stator 17, which surrounds the rotor 16 and is fixed to the inner
surface of the motor housing member 12. The rotor 16 includes a
rotor core 16a, which is fixed to the rotation shaft 20 and rotated
integrally with the rotation shaft 20, and a plurality of permanent
magnets 16b, which are embedded in the rotor core 16a. The stator
17 includes a stator core 17a, which is annular and fixed to the
inner surface of the motor housing member 12, and coils 17b, which
are wound around the teeth (not shown) of the stator core 17a.
Leads R for U, V, and W phases (only one lead shown in FIG. 1)
extend from the ends of the coils 17b that face toward the shaft
support 21.
[0018] A fixed scroll 22 is arranged between the shaft support 21
and the open end 121h of the motor housing member 12. The fixed
scroll 22 includes a circular base plate 22a, a
cylindrically-formed peripheral wall 22b projecting from the
periphery of the base plate 22a, and a fixed spiral wall 22c
projecting from the base plate 22a at the inner side of the
peripheral wall 22b.
[0019] An eccentric shaft 20a projects from the end face of the
rotation shaft 20 that faces toward the open end 121h. The
eccentric shaft 20a is eccentric to the rotation axis L of the
rotation shaft 20. The eccentric shaft 20a supports a bushing 20b.
A movable scroll 23 is supported by the bushing 20b to be rotatable
relative to the bushing 20b. A bearing B3 is arranged between the
movable scroll 23 and the bushing 20b. The movable scroll 23
includes a circular base plate 23a and a movable spiral wall 23b
projecting from the base plate 23a toward the base plate 22a of the
fixed scroll 22.
[0020] The fixed spiral wall 22c of the fixed scroll 22 and the
movable spiral wall 23b of the movable scroll 23 are engaged with
each other. The fixed spiral wall 22c has a distal surface in
contact with the base plate 23a of the movable scroll 23. The
movable spiral wall 23b has a distal surface in contact with the
base plate 22a of the fixed scroll 22. The base plate 22a and the
fixed spiral wall 22c of the fixed scroll 22 and the base plate 23a
and the movable spiral wall 23b of the movable scroll 23 define a
compression chamber 25.
[0021] As shown in FIG. 2, the end surface of the shaft support 21
that faces the movable scroll 23 includes an accommodating recess
21h. The accommodating recess 21h accommodates an annular movable
member 28 surrounding the bushing 20b. A clearance C1 is formed
between the movable member 28 and the shaft support 21 in the
radial direction of the rotation shaft 20. Thus, the movable member
28 is movable in the radial direction of the rotation shaft 20 in
the range of a distance corresponding to the clearance C1. In the
following description, the terms "axial direction", "radial
direction", and "circumferential direction" refer to the axial
direction, the radial direction, and the circumferential direction
of the rotation shaft 20, respectively.
[0022] A rotation restriction mechanism 27 is arranged between the
base plate 23a of the movable scroll 23 and the shaft support 21.
The rotation restriction mechanism 27 includes a plurality of
circular holes 27a, which are recesses arranged in the outer
circumferential portion of the end surface of the base plate 23a of
the movable scroll 23, and a plurality of pins 27b (only one shown
in FIG. 1), which project from the outer circumferential portion of
the shaft support 21 and are loosely fitted into the circular holes
27a. The pins 27b are integrated with the movable member 28.
[0023] As shown in FIGS. 2 and 3, the shaft support 21 includes a
plurality of cylindrical valve chambers 21b extending in the axial
direction. The valve chambers 21b are arranged in intervals in the
circumferential direction. Each valve chamber 21b has one end
facing toward the movable scroll 23 that opens in the accommodating
recess 21h and another end facing away from the movable scroll 23
that is closed by a cover 21f, which has the form of a circular
plate. The cover 21f is coupled to the end surface of the shaft
support 21 that faces toward the end wall 12a of the motor housing
member 12.
[0024] Each valve chamber 21b accommodates a cylindrical valve body
21v. Each valve body 21v has a semispherical distal end that faces
toward the movable scroll 23. An annular seal 21s is arranged in
the outer surface of each valve body 21v. The seal 21s seals the
gap between the valve body 21v and the valve chamber 21b and
divides the valve chamber 21b into a primary void K1 and a
secondary void K2. The primary void K1 is located between the
movable scroll 23 and the secondary void K2.
[0025] As shown in FIG. 2, the shaft support 21 incorporates an
electromagnetic switching valve 70. In addition, the shaft support
21 includes a branch passage 71 extending from the switching valve
70 to the valve chambers 21b. The branch passage 71 includes a main
passage 71a, which is in communication with the switching valve 70,
and an annular passage 71b, which extends in the circumferential
direction and communicates the main passage 71a and the secondary
voids K2 of the valve chambers 21b.
[0026] The end surface of the movable member 28 that faces away
from the movable scroll 23 includes circular fitting recesses 28k
at positions corresponding to the valve chambers 21b. The surface
of each fitting recess 28k is tapered so that the diameter of the
fitting recess 28k increases from the side that faces toward the
movable scroll 23 to the end surface that faces away from the
movable scroll 23. The movable member 28 also includes
communication passages 28r that extend in the axial direction and
are in communication with the corresponding fitting recesses
28k.
[0027] An annular, flat seat member 24 is arranged between the
movable scroll 23 and the movable member 28. The seat member 24
includes a peripheral portion held between the fixed scroll 22 and
the shaft support 21. The seat member 24 is fixed positioned
relative to the motor housing member 12. The seat member 24
includes communication holes 24g that communicate the corresponding
communication passages 28r and a gap between the seat member 24 and
the movable scroll 23.
[0028] As shown in FIG. 1, when the rotation shaft 20 is driven by
the electric motor M and rotated, the movable scroll 23, which is
coupled to the rotation shaft 20 by the eccentric shaft 20a, orbits
about the axis of the fixed scroll 22 (the rotation axis L of the
rotation shaft 20) without rotating. The rotation restriction
mechanism 27 prevents rotation of the movable scroll 23 while
permitting the orbital motion. The orbital motion of the movable
scroll 23 reduces the volume of the compression chamber 25. Thus,
the fixed scroll 22 and the movable scroll 23 form a compression
unit P that draws in and discharges refrigerant.
[0029] The peripheral wall 22b of the fixed scroll 22 and the
outermost portion in the movable spiral wall 23b of the movable
scroll 23 define a suction chamber 31 that is in communication with
the compression chamber 25. The peripheral wall 22b of the fixed
scroll 22 has an outer surface including a recess 221b. The area
surrounded by the recess 221b and the inner surface of the motor
housing member 12 forms a suction passage 32 that is connected to
the suction chamber 31 through a through hole 221h in the
peripheral wall 22b of the fixed scroll 22. A through hole 211,
which extends through the peripheral portions of the shaft support
21 and the cover 21f, and a through hole 24h, which extends through
the peripheral portion of the seat member 24, connect the suction
passage 32 to the motor chamber 121.
[0030] The motor housing member 12 includes a suction port 122
connected to an external refrigerant circuit 19. Refrigerant (gas)
is drawn into the motor chamber 121 from the external refrigerant
circuit 19 through the suction port 122. The refrigerant in the
motor chamber 121 is then sent to the compression chamber 25
through the through hole 211, the through hole 24h, the suction
passage 32, the through hole 221h, and the suction chamber 31.
Accordingly, the motor chamber 121, the through hole 211, the
through hole 24h, the suction passage 32, the through hole 221h,
and the suction chamber 31 form a suction pressure region.
[0031] The refrigerant in the compression chamber 25 is compressed
by the orbiting motion (discharging motion) of the movable scroll
23, forced through a discharge valve 22v of a discharge port 22e,
and discharged into a discharge chamber 131 of the discharge
housing member 13.
[0032] A chamber-forming wall 41 is formed integrally with the
discharge housing member 13. An oil-separating chamber 42 is formed
between the discharge housing member 13 and the chamber-forming
wall 41. The oil-separating chamber 42 is in communication with the
discharge chamber 131 through a discharge port 43 formed in the
discharge housing member 13. The refrigerant in the discharge
chamber 131 is sent to the oil-separating chamber 42 through the
discharge port 43.
[0033] The oil-separating chamber 42 accommodates an oil-separating
cylinder 44. The oil-separating cylinder 44 includes a large
diameter portion 441, which is fitted in the oil-separating chamber
42, and a small diameter portion 442, which has a smaller diameter
than the oil-separating chamber 42 and is located under the large
diameter portion 441. Refrigerant flows into the oil-separating
chamber 42 through the discharge port 43, swirls around the small
diameter portion 442, and then flows into the oil-separating
cylinder 44 from a lower opening in the small diameter portion 442.
The refrigerant further flows from the oil-separating cylinder 44
to the external refrigerant circuit 19 and then returns to the
motor chamber 121. Lubricating oil is separated from the
refrigerant when the refrigerant swirls around the small diameter
portion 442. The separated lubricating oil falls into the lower
portion of the oil-separating chamber 42. Accordingly, the
discharge port 22e, the discharge chamber 131, the discharge port
43, and the oil-separating chamber 42 form a discharge pressure
region.
[0034] An inverter cover 51 made of metal (aluminum in the present
embodiment) is fixed to the end wall 12a of the motor housing
member 12. The inverter cover 51 and the end wall 12a of the motor
housing member 12 define a chamber that accommodates a motor
driving circuit 52 fixed to the outer surface of the end wall 12a.
Thus, in the present embodiment, the compression unit P, the
electric motor M, and the motor driving circuit 52 are arranged in
this order in the axial direction.
[0035] The end wall 12a of the motor housing member 12 includes a
through hole 12b that receives a sealing terminal 53. The sealing
terminal 53 includes three sets of a metal terminal 54 and a glass
insulator 55 (only one set shown in FIG. 1). The metal terminals 54
extend through the motor housing member 12 to electrically connect
the electric motor M to the motor driving circuit 52. Each glass
insulator 55 fixes the corresponding metal terminal 54 to the end
wall 12a and insulates the metal terminal 54 from the end wall 12a.
Each metal terminal 54 has a first end connected to the motor
driving circuit 52 by a cable (not shown) and a second end
extending into the motor housing member 12.
[0036] An insulative resin cluster block 56 is fixed to the outer
surface of the stator core 17a. The cluster block 56 accommodates
three connection terminals 56a (only one shown in the FIG. 1). The
connection terminals 56a electrically connect the leads R to the
metal terminals 54. The motor driving circuit 52 supplies power to
the coils 17b through the metal terminals 54, the connection
terminals 56a, and the leads R. This integrally rotates the rotor
16 and the rotation shaft 20.
[0037] As shown in FIG. 2, an annular seal 61, which is in contact
with the surface of the rotation shaft 20, divides the insertion
hole 21a of the shaft support 21 into a back pressure chamber 62
and an accommodating chamber 63. The back pressure chamber 62 is
located between the seal 61 and the movable scroll 23. The
accommodating chamber 63 accommodates the bearing B1. A snap ring
64 is fitted to a section of the insertion hole 21a of the shaft
support 21 that is located in the back pressure chamber 62. The
snap ring 64 restricts movement of the seal 61 into the back
pressure chamber 62.
[0038] The movable scroll 23 and the seat member 24 include a first
oil passage 65 extending through the movable spiral wall 23b and
the base plate 23a near the center of the movable scroll 23. The
first oil passage 65 has an end that opens to the compression
chamber 25 and another end that opens to the back pressure chamber
62. Some of the refrigerant compressed in the compression chamber
25 is supplied to the back pressure chamber 62 through the first
oil passage 65. The refrigerant supplied to the back pressure
chamber 62 flows through the inner side of the seat member 24 into
the circular holes 27a. The pressure of the refrigerant supplied
into the back pressure chamber 62 and the circular holes 27a
presses the movable scroll 23 toward the fixed scroll 22. Thus, in
the present embodiment, the circular holes 27a and the back
pressure chamber 62 form a back pressure region located between the
movable scroll 23 and the movable member 28 in the motor housing
member 12. The back pressure region applies force to the movable
scroll 23, and the force presses the movable scroll 23 against the
fixed scroll 22.
[0039] When refrigerant enters the gap between the seat member 24
and the movable scroll 23, the refrigerant flows to the primary
voids K1 of the valve chambers 21b through the corresponding
communication holes 24g and the communication passages 28r. The
primary voids K1 function as part of the back pressure region due
to the pressure of the refrigerant flowing into the primary voids
K1.
[0040] The switching valve 70 is in communication with the
oil-separating chamber 42 through the second oil passage 68, which
extends through the shaft support 21, the seat member 24, the fixed
scroll 22, and the discharge housing member 13. Further, the
switching valve 70 is in communication with the motor chamber 121
through a communication passage 69 formed in the shaft support 21
and the cover 21f. The switching valve 70 operates so that the
secondary voids K2 of the valve chambers 21b are in communication
with the second oil passage 68 through the branch passage 71 when
the compressor 10 operates at a high rotation speed and so that the
secondary voids K2 are in communication with the communication
passage 69 through the branch passage 71 when the compressor 10
operates at a low rotation speed. In other words, the switching
valve 70 switches between a state in which the secondary voids K2
are in communication with a suction pressure region and a state in
which the secondary voids K2 are in communication with a discharge
pressure region. The suction pressure region is a low pressure
region, the pressure of which is lower than that of the primary
voids K1. The primary voids K1 are part of the back pressure
region. The discharge pressure region is a high pressure region,
the pressure of which is higher than that of the primary voids
K1.
[0041] The operation of the first embodiment will now be
described.
[0042] As shown in FIG. 4, when the compressor 10 operates at a
high rotation speed, the switching valve 70 brings the secondary
voids K2 of the valve chambers 21b into communication with the
second oil passage 68 through the branch passage 71. This allows
the lubricating oil flowing in the second oil passage 68 from the
oil-separating chamber 42 to be sent into the secondary voids K2 of
the valve chambers 21b through the switching valve 70 and the
branch passage 71. Consequently, the secondary voids K2 become part
of the discharge pressure region.
[0043] The difference between the pressure in the primary voids K1
and the pressure in the secondary voids K2 moves the valve bodies
21v toward the movable scroll 23. The distal end of each valve body
21v that faces toward the movable scroll 23 is guided by the
surface of the corresponding fitting recess 28k into the fitting
recess 28k. Accordingly, the movable member 28 is pressed by the
valve bodies 21v toward the movable scroll 23 and received by the
seat member 24. Thus, the movable member 28 is held between the
valve bodies 21v and the seat member 24. This restricts movement of
the movable member in the radial direction. Further, the engagement
between the valve bodies 21v and the respective fitting recesses
28k also restricts the radial movement of the movable member 28 and
changes the movable range of the movable member 28 in the radial
direction. Thus, the orbital radius of the movable scroll 23 is
decreased compared to when the restriction of the movable member 28
is canceled and the movable member 28 can move freely. As a result,
the movable spiral wall 23b does not contact the fixed spiral wall
22c when the compressor 10 operates at a high rotation speed. This
reduces noise that would be caused by contact between the fixed
spiral wall 22c and the movable spiral wall 23b during high speed
rotation.
[0044] As shown in FIG. 2, when the compressor 10 operates at a low
rotation speed, the switching valve 70 brings the secondary voids
K2 of the valve chambers 21b into communication with the
communication passage 69 through the branch passage 71. This allows
the refrigerant in the valve chambers 21b to flow into the motor
chamber 121 through the branch passage 71, the switching valve 70,
and the communication passage 69. Consequently, the secondary voids
K2 become part of the suction pressure region.
[0045] The difference in the pressure in the primary voids K1 and
the pressure in the secondary voids K2 moves the valve bodies 21v
away from the movable scroll 23. This releases the movable member
28 from the valve bodies 21v and the seat member 24 and disengages
the valve bodies 21v from the fitting recesses 28k thereby allowing
the movable member 28 to move freely. As a result, the movable
range of the movable member 28 in the radial direction is changed.
Thus, the orbital radius of the movable scroll 23 is increased
compared to when the radial movement of the movable member 28 is
restricted. As a result, the movable spiral wall 23b is in contact
with the fixed spiral wall 22c when the compressor 10 operates at
low rotation speed. This suppresses leakage of refrigerant from the
compression chamber 25 during low speed rotation. In the present
embodiment, the valve chamber 21b, the valve body 21v, the primary
void K1, the secondary void K2, the branch passage 71, and the
switching valve 70 form a switching mechanism.
[0046] The orbital radius of the movable scroll 23 is increased or
decreased when the bushing 20b slides or swings to move in the
radial direction relative to the eccentric shaft 20a and thereby
permit radial movement of the movable scroll 23.
[0047] The advantage of the first embodiment will now be
described.
[0048] (1) The movable member 28 is arranged in the shaft support
21. In addition, the pins 27b, the circular holes 27a, and the
movable member 28 form the rotation restriction mechanism 27. The
movable member 28 is switched between a state in which the radial
movement of the movable member 28 is restricted and a state in
which the restriction is canceled and the movable member 28 can
move freely. This allows the movable range of the movable member 28
and the orbital radius of the movable scroll 23 to be changed. When
the compressor 10 operates at high rotation speed, the radial
movement of the movable member 28 is restricted to reduce the
movable range of the movable member 28 in the radial direction.
Thus, the orbital radius of the movable scroll 23 is decreased so
that the movable spiral wall 23b does not contact the fixed spiral
wall 22c. This reduces noise that would be caused by contact
between the fixed spiral wall 22c and the movable spiral wall 23b
during high speed rotation. Further, when the compressor 10
operates at low rotation speed, the restriction of the movable
member 28 is canceled so that the movable member can move freely.
This increases the movable range of the movable member 28 in the
radial direction and allows the orbital radius of the movable
scroll 23 to be increased. Thus, the movable spiral wall 23b
contacts the fixed spiral wall 22c. This suppresses leakage of
refrigerant from the compression chamber 25 during low speed
rotation.
[0049] (2) The shaft support 21 includes the valve chambers 21b,
each accommodating the corresponding valve body 21v that presses
the movable member 28 toward the movable scroll 23. Thus, the
radial movement of the movable member 28 can be restricted by
moving the valve bodies 21v toward the movable scroll 23 so that
the valve bodies 21v press the movable member 28 toward the movable
scroll 23.
[0050] (3) The shaft support 21 includes the switching valve 70,
which switches between a state in which the secondary voids K2 are
in communication with the suction pressure region having a lower
pressure than the primary voids K1, which function as the back
pressure region, and a state in which the secondary voids K2 are in
communication with the discharge pressure region having a higher
pressure than the primary voids K1. When the switching valve 70
brings the secondary voids K2 into communication with the discharge
pressure region, the difference between the pressure in the primary
voids K1 and the pressure in the secondary voids K2 moves the valve
bodies 21v toward the movable scroll 23. Accordingly, the valve
bodies 21v press the movable member 28 toward the movable scroll 23
and easily restrict the radial movement of the movable member 28.
Further, when the switching valve 70 brings the secondary voids K2
into communication with the suction pressure region, the difference
between the pressure in the primary voids K1 and the pressure in
the secondary voids K2 moves the valve bodies 21v away from the
movable scroll 23. Thus, the valve bodies 21v no longer press the
movable member 28 against the movable scroll 23, and the
restriction of the radial movement of the rotation shaft 20 is
easily cancelled.
[0051] (4) The movable member 28 includes the communication
passages 28r that communicate the back pressure region and the
primary voids K1. This ensures that the primary voids K1 function
as part of the back pressure region and contrasts to a structure in
which the movable member 28 does not include the communication
passages 28r. Consequently, when the secondary voids K2 become part
of the discharge pressure region due to actuation of the switching
valve 70, the difference between the pressure in the primary voids
K1 and the pressure in secondary voids K2 is ensured to move the
valve bodies 21v toward the movable scroll 23. Further, when the
secondary voids K2 become part of the suction pressure region due
to actuation of the switching valve 70, the difference between the
pressure in the primary voids K1 and the pressure in the secondary
voids K2 is ensured to move the valve bodies 21v away from the
movable scroll 23.
[0052] (5) The shaft support 21 includes a plurality of valve
chambers 21b separated from one another in the circumferential
direction. The shaft support 21 also includes the branch passage 71
extending from the switching valve 70 to the valve chambers 21b.
This facilitates restriction of the radial movement of the movable
member 28 and contrasts to a structure in which the shaft support
21 includes only one valve chamber 21b and the radial movement of
the movable member 28 is restricted by only one valve body 21v.
[0053] (6) The movable member 28 includes the fitting recesses 28k
to which the corresponding valve bodies 21v can be fitted. When the
switching valve 70 brings the secondary voids K2 into communication
with the discharge pressure region and the difference between the
pressure in the primary voids K1 and the pressure in the secondary
voids K2 moves the valve bodies 21v toward the movable scroll 23,
the valve bodies 21v are fitted to the corresponding fitting
recesses 28k. This further facilitates the restriction of radial
movement of the movable member 28.
[0054] (7) The seat member 24 is arranged between the movable
scroll 23 and the movable member 28. The seat member 24 is fixed to
the motor housing member 12 and receives the movable member 28 that
is pressed toward the movable scroll 23 by the valve bodies 21v.
This facilitates the restriction of radial movement of the movable
member 28 compared to a structure in which the radial movement of
the movable member 28 is restricted by holding the movable member
28 between the valve bodies 21v and the movable scroll 23, for
example.
[0055] (8) Each valve body 21v includes the semispherical distal
end that faces toward the movable scroll 23. In addition, the
surface of each fitting recess 28k is tapered so that the diameter
of the fitting recess 28k increases from the side that faces toward
the movable scroll 23 to the end surface that faces away from the
movable scroll 23. Thus, when the difference in the pressure in the
primary voids K1 and the pressure in the secondary voids K2 moves
the valve bodies 21v toward the movable scroll 23, the distal end
of each valve body 21v is guided by the surface of the
corresponding fitting recess 28k and inserted into the fitting
recess 28k. This facilitates the engagement between the valve body
21v and the fitting recess 28k.
Second Embodiment
[0056] Referring to FIGS. 5 and 6, the second embodiment will now
be described. Same reference numerals are given to those components
that are the same as the corresponding components of the first
embodiment. Such components will not be described in detail.
[0057] As shown in FIG. 5, the end surface of the movable member 28
that faces away from the movable scroll 23 includes a conical
projection 81. The conical projection 81 includes a conical
projection surface 81a that surrounds the bushing 20b and has a
diameter that decreases as the movable scroll 23 becomes farther.
Further, an annular seal 28s is arranged in the outer
circumferential surface of the movable member 28. The seal 28s has
an outer surface that is located radially outward from the outer
circumferential surface of the movable member 28. Accordingly, a
clearance C2 is formed between the movable member 28 and the shaft
support 21 in the radial direction. The seal 28s can be elastically
deformed to allow the movable member 28 to move in the radial
direction in the range of the distance of the clearance C2.
[0058] Further, the accommodating recess 21h accommodates a tip
seal 29 arranged on the end surface of the movable member 28 that
faces away from the movable scroll 23. The tip seal 29 seals the
gap between the shaft support 21 and the movable member 28. In
addition, the end surface of the movable member 28 that faces away
from the movable scroll 23 includes an accommodating groove 28g
that can accommodate the tip seal 29. The accommodating recess 21h
is divided into a primary void K1 and a secondary void K2. The
primary void K1 is located between the movable scroll 23 and the
secondary void K2, and the secondary void K2 is located between the
seal 28s and the tip seal 29.
[0059] The shaft support 21 includes a communication flow passage
83 that communicates the switching valve 70 and the secondary void
K2. The primary void K1 is in communication with the first oil
passage 65, which is in communication with the back pressure
chamber 62. Thus, in the second embodiment, the primary void K1
functions as part of the back pressure region.
[0060] The shaft support 21 includes a conical recess 82 on the
side that faces the movable member 28. The conical recess 82
includes a conical recess surface 82a that surrounds the bushing
20b and has a diameter that decreases as the movable member 28
becomes farther. The conical projection 81 is movable toward and
away from the conical recess 82.
[0061] The operation of the second embodiment will now be
described.
[0062] As shown in FIG. 6, when the compressor 10 operates at a
high rotation speed, the switching valve 70 brings the secondary
void K2 into communication with the communication passage 69
through the communication flow passage 83. This allows the
refrigerant in the secondary void K2 to flow into the motor chamber
121 through the communication flow passage 83, the switching valve
70, and the communication passage 69. Consequently, the secondary
void K2 becomes part of the suction pressure region.
[0063] The difference between the pressure in the primary void K1
and the pressure in the secondary void K2 moves the movable member
28 away from the movable scroll 23. This moves the conical
projection 81 toward the conical recess 82 and brings the conical
projection surface 81a and conical recess surface 82a into contact
with each other. Thus, the conical projection 81 is fitted into the
conical recess 82 and thereby restricts the radial movement of the
movable member 28. This changes the movable range of the movable
member 28 in the radial direction. The orbital radius of the
movable scroll 23 is decreased compared to when the movable member
28 is not restricted and freely movable. As a result, when the
compressor 10 is operating at a high rotation speed, the movable
spiral wall 23b is not in contact with the fixed spiral wall 22c.
This reduces noise that would be caused by contact between the
fixed spiral wall 22c and the movable spiral wall 23b during high
speed rotation.
[0064] As shown in FIG. 5, when the compressor 10 operates at a low
rotation speed, the switching valve 70 brings the secondary void K2
into communication with the second oil passage 68 through the
communication flow passage 83. This allows the lubricating oil
flowing in the second oil passage 68 from the oil-separating
chamber 42 to flow into the secondary void K2 through the switching
valve 70 and the communication flow passage 83. Consequently, the
secondary void K2 becomes part of the discharge pressure
region.
[0065] The difference between the pressure in the primary void K1
and the pressure in the secondary void K2 moves the movable member
28 toward the movable scroll 23. This moves the conical projection
81 away from the conical recess 82 and allows the movable member 28
to move freely. Thus, the movable range of the movable member 28 in
the radial direction is changed. The orbital radius of the movable
scroll 23 is increased compared to when the radial movement of the
movable member 28 is restricted. As a result, when the compressor
10 operates at a low rotation speed, the movable spiral wall 23b is
in contact with the fixed spiral wall 22c. This suppresses leakage
of refrigerant from the compression chamber 25 during low speed
rotation. In the present embodiment, the conical projection 81, the
conical recess 82, the primary void K1, the secondary void K2, the
communication passage 69, and the switching valve 70 form a
switching mechanism.
[0066] Accordingly, the second embodiment has the following
advantages in addition to advantage (1) of the first
embodiment.
[0067] (9) The second embodiment does not require the valve
chambers 21b or the valve bodies 21v of the first embodiment and
has a simple structure.
[0068] It should be apparent to those skilled in the art that the
present invention may be embodied in many other specific forms
without departing from the spirit or scope of the invention.
Particularly, it should be understood that the present invention
may be embodied in the following forms.
[0069] In the first embodiment, the movable member 28 does not have
to include the fitting recesses 28k. Instead, the valve bodies 21v
may be pressed against the end surface of the movable member 28
that faces away from the movable scroll 23 to restrict radial
movement of the movable member 28 with the friction produced
between the valve bodies 21v and the movable member 28.
[0070] In the first embodiment, the communication passages 28r may
be omitted. In this case, the primary voids K1 can still become the
back pressure region due to the refrigerant flowing into the
primary voids K1 from the back pressure chamber 62 through the gap
between the movable member 28 and the shaft support 21.
[0071] In the first embodiment, the number of the valve chambers
21b is not limited.
[0072] In the first embodiment, the seat member 24 may be omitted.
The radial movement of the movable member 28 may be restricted by
holding the movable member 28 between the valve bodies 21v and the
movable scroll 23, for example.
[0073] In the first embodiment, the shape of the valve body 21v is
not limited. For example, the valve body 21v may be spherical.
[0074] In the first embodiment, the surface of the fitting recesses
28k may extend in the axial direction, for example.
[0075] In the above embodiment, the secondary void K2 does not have
to be in communication with the suction pressure region or the
discharge pressure region as long as the secondary void K2 is in
communication with a low pressure region that has a lower pressure
than the back pressure region or a high pressure region that has a
higher pressure than the back pressure region.
[0076] The bushing 20b may be fixed to the eccentric shaft 20a, and
the radial movement of the movable scroll 23 may be permitted by a
gap between the movable scroll 23 and the bearing B3 or a gap
between the bushing 20b and the bearing B3.
[0077] In the above embodiments, the secondary void K2 receives
lubricating oil from the oil-separating chamber 42 through the
second oil passage 68. However, the secondary void K2 may be in
communication with the discharge chamber 131 so that refrigerant
having the discharge pressure is delivered to the secondary void
K2.
[0078] The movable scroll 23 may include a plurality of pins that
are integrated with the movable scroll 23, and the movable member
28 may include a plurality of circular holes into which the
respective pins are loosely fitted.
[0079] The present invention may be embodied in a scroll compressor
that is directly driven by a driving source such as an engine,
instead of being driven by the electric motor M.
[0080] The present examples and embodiments are to be considered as
illustrative and not restrictive and the invention is not to be
limited to the details given herein, but may be modified within the
scope and equivalence of the appended claims.
* * * * *