U.S. patent application number 09/846938 was filed with the patent office on 2002-01-24 for anti-rotation mechanism for movable scroll in scroll compressor.
Invention is credited to Fujii, Toshiro, Murakami, Kazuo, Nakane, Yoshiyuki, Yamamoto, Shinya, Yokomachi, Naoya.
Application Number | 20020009379 09/846938 |
Document ID | / |
Family ID | 16354372 |
Filed Date | 2002-01-24 |
United States Patent
Application |
20020009379 |
Kind Code |
A1 |
Nakane, Yoshiyuki ; et
al. |
January 24, 2002 |
Anti-rotation mechanism for movable scroll in scroll compressor
Abstract
An improved scroll compressor having a movable scroll that
orbits without being inclined. The compressor has a fixed scroll
formed in the housing. The movable scroll is accommodated in the
housing and mates with the fixed scroll. The movable scroll is
driven by a drive shaft via a crank mechanism. A flange is formed
at the periphery of the movable scroll and lies perpendicular to
the drive shaft. A groove is formed in the housing. The groove is
slightly wider than the thickness of the flange. The flange is
slidably accommodated in the groove. Support holes extend through
the flange. A pin is supported in each support hole. The ends of
each pin are received in guide holes. Since engagement of the
flange and the groove prevents the movable scroll from being
inclined, the pin is maintained parallel to the guide holes and
follows the wall of the guide holes. As a result, uneven wear of
the pins and the guide holes is avoided.
Inventors: |
Nakane, Yoshiyuki;
(Kariya-shi, JP) ; Fujii, Toshiro; (Kariya-shi,
JP) ; Yokomachi, Naoya; (Kariya-shi, JP) ;
Yamamoto, Shinya; (Kariya-shi, JP) ; Murakami,
Kazuo; (Kariya-shi, JP) |
Correspondence
Address: |
MORGAN & FINNEGAN, L.L.P.
3545 Park Avenue
New York
NY
10154-0053
US
|
Family ID: |
16354372 |
Appl. No.: |
09/846938 |
Filed: |
May 1, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09846938 |
May 1, 2001 |
|
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09349307 |
Jul 8, 1999 |
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6287096 |
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Current U.S.
Class: |
418/55.2 ;
418/55.3 |
Current CPC
Class: |
F01C 17/063
20130101 |
Class at
Publication: |
418/55.2 ;
418/55.3 |
International
Class: |
F04C 018/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 10, 1998 |
JP |
10-196230 |
Claims
What is claimed is:
1. A scroll compressor for compressing gas comprising: a housing
having an annular groove that includes a pair of walls facing each
other; a fixed scroll formed in the housing; a drive shaft
rotatably supported in the housing; a movable scroll accommodated
in the housing to mate with the fixed scroll; a crank mechanism
located between the drive shaft and the movable scroll for driving
the movable scroll in accordance with the rotation of the drive
shaft; a projection extending radially from the movable scroll
along a plane perpendicular to the axis of the drive shaft, wherein
the projection is located in the annular groove and slides along
the walls of the annular groove, wherein the projection has a
thickness measured in the axial direction of the drive shaft, and
wherein the distance between the groove walls is greater than the
thickness of the projection by a predetermined value; and a
restriction mechanism for inhibiting rotation of the movable scroll
with respect to the axis of the movable scroll and for permitting
orbital movement of the movable scroll, wherein the restriction
mechanism includes a restriction member supported by the projection
or the groove walls.
2. The scroll compressor according to claim 1, wherein the distance
between the groove walls is greater than the thickness of the
projection by 0.01 mm to 0.2 mm.
3. The scroll compressor according to claim 2 further comprising a
spacer located between the projection and the one of the groove
walls to adjust the distance between the projection and the other
of the groove walls to the predetermined value.
4. The scroll compressor according to claim 1, wherein the
restriction mechanism includes: a plurality of support holes formed
on either the projection or the housing, wherein the support holes
are formed at equal intervals on an imaginary circle that is
coaxial with the axis of the movable scroll; and a plurality of
guide holes formed on the other of the projection or the housing,
and wherein each guide hole corresponds to a support hole.
5. The scroll compressor according to claim 1, wherein the
restriction member is a pin that is parallel with the drive shaft,
wherein the pin is supported by a support hole formed either in the
projection or in the housing, wherein the other of the projection
and the housing has a guide hole that faces the support hole and
receives part of the pin, wherein the axis of the support hole and
the guide hole are parallel to the axis of the drive shaft, and
wherein the guide hole has an inner diameter greater than that of
the support hole so that the pin orbits within the guide hole while
remaining parallel to the drive shaft.
6. The scroll compressor according to claim 5, wherein the support
hole is a through hole formed in the projection, wherein the guide
hole is a first guide hole formed in one of the groove walls, and a
second guide hole is formed in the other groove wall, wherein a
mid-section of the pin engages the support hole, and wherein the
ends of the pin are loosely received by the first and the second
guide holes.
7. The scroll compressor according to claim 5, wherein the support
hole is a first support hole formed in one of the groove walls, and
a second support hole is formed in the other groove wall, wherein
the guide hole is a through hole formed in the projection to
correspond to the support holes, wherein the ends of the pin are
supported by the support holes, and wherein a mid-section of the
pin is loosely fitted in the guide hole.
8. The scroll compressor according to claim 5, wherein the support
hole is a blind hole formed in the projection, wherein the guide
hole is formed in one of the groove walls to face the opening of
the support hole, wherein one end of the pin is supported by the
support hole, and wherein the other end of the pin is loosely
received in the guide hole.
9. The scroll compressor according to claim 5 further comprising a
recess formed around the opening of the support hole.
10. The scroll compressor according to claim 1, wherein the
restriction mechanism includes a support hole, which is a through
hole formed in the projection, wherein each groove wall has a guide
hole facing the support hole, wherein the guide holes have an inner
diameter greater than that of the support hole, wherein the
restriction member is a ball located within the annular groove,
wherein the ball is rotatably retained in the support hole and
loosely fitted in each guide hole.
11. The scroll compressor according to claim 1, wherein the
projection is a flange.
12. The scroll compressor according to claim 1, wherein the
projection is a plurality of panels radially extending from the
movable scroll.
13. A scroll compressor for compressing gas comprising: a housing;
a fixed scroll formed in the housing; a drive shaft rotatably
supported in the housing; a movable scroll accommodated in the
housing to mate with the fixed scroll and driven in accordance with
the rotation of the drive shaft; a regulating means for regulating
inclination of the movable scroll with respect to the axis of the
drive shaft, wherein the regulating means is arranged between the
housing and the movable scroll; and a restriction means for
inhibiting rotation of the movable scroll with respect to the axis
of the movable scroll and for permitting orbital movement of the
movable scroll.
14. The scroll compressor according to claim 13, wherein the
housing has an annular groove that includes a pair of walls facing
each other, wherein the regulating means includes the annular
groove and a projection extending radially from the movable scroll
along a plane perpendicular to the axis of the drive shaft, wherein
the projection has a thickness measured in the axial direction of
the drive shaft, wherein the distance between the groove walls is
greater than the thickness of the projection by a predetermined
value, wherein the projection is located in the annular groove and
slides along the groove walls.
15. The scroll compressor according to claim 14, wherein the
projection is a flange.
16. The scroll compressor according to claim 14, wherein the
projection is a plurality of panels radially extending from the
movable scroll.
17. The scroll compressor according to claim 14, wherein the
regulating means further includes a spacer located between the
projection and the one of the groove walls to adjust the distance
between the projection and the other of the groove walls to the
predetermined value.
18. The scroll compressor according to claim 14, wherein the
distance between the groove walls is greater than the thickness of
the projection by 0.01 mm to 0.2 mm.
19. The scroll compressor according to claim 14, wherein the
restriction means includes a restriction member supported by the
projection or the groove walls.
20. The scroll compressor according to claim 19, wherein the
restriction means includes: a plurality of support holes formed on
either the projection or the housing, wherein the support holes are
formed at equal intervals on an imaginary circle that is coaxial
with the axis of the movable scroll; and a plurality of guide holes
formed on the other of the projection or the housing, and wherein
each guide hole corresponds to a support hole.
21. The scroll compressor according to claim 19, wherein the
restriction member is a pin that is parallel with the drive shaft,
wherein the pin is supported by a support hole formed either in the
projection or in the housing, wherein the other of the projection
and the housing has a guide hole that faces the support hole and
receives part of the pin, wherein the axis of the support hole and
the guide hole are parallel to the axis of the drive shaft, and
wherein the guide hole has an inner diameter greater than that of
the support hole so that the pin orbits within the guide hole while
remaining parallel to the drive shaft.
22. The scroll compressor according to claim 21, wherein the
support hole is a through hole formed in the projection, wherein
the guide hole is a first guide hole formed in one of the groove
walls, and a second guide hole os formed in the other groove wall,
wherein a mid-section of the pin engages the support hole, and
wherein the ends of the pin are loosely received by the first and
the second guide holes.
23. The scroll compressor according to claim 21, wherein the
support hole is a first support hole formed in on eof the groove
walls, and a second support hole is formed in the other groove
wall, wherein the guide hole is a through hole formed in the
projection to correspond to the support hole, wherein the ends of
the pin are supported by the support holes, and wherein a
mid-section of the pin is loosely fitted in the guide hole.
24. The scroll compressor according to claim 21, wherein the
support hole is a blind hole formed in the projection, wherein the
guide hole is formed in one of the groove walls to face the opening
of the support hole, wherein one end of the pin is supported by the
support hole, and wherein the other end of the pin is loosely
received in the guide hole.
25. The scroll compressor according to claim 21 further comprising
a recess formed around the opening of the support hole.
26. The scroll compressor according to claim 19, wherein the
restriction mechanism includes a support hole, which is a through
hole formed in the projection, wherein each groove wall has a guide
hole facing the support hole, wherein the guide hole has an inner
diameter greater than that of the support hole, wherein the
restriction member is a ball located within the annular groove,
wherein the ball is rotatably retained in the support hole and
loosely fitted in each guide hole.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to scroll compressor for
compressing gas.
[0002] FIG. 10 shows such a scroll compressor, which was disclosed
in Japanese Unexamined Patent Publication No. 5-321850. The
compressor includes a fixed scroll 52 formed in a center housing
part 51. A drive shaft 56 is rotatably supported by a front housing
part 55. The front housing part 55 and the center housing part 51
form a scroll housing for accommodating a movable scroll 53. A
compression chamber 54 is defined between the movable scroll 53 and
the fixed scroll 52. The movable scroll 53 is supported by a crank
mechanism 56a. The crank mechanism 56a converts rotation of the
drive shaft 56 into eccentric (orbital) movement of the movable
scroll 53 relative to the drive shaft 56. Orbital movement of the
movable scroll 53 causes the volume of the compression chamber 54
to change from the maximum to the minimum and then from the minimum
to the maximum. As the volume of the compression chamber 54 is
decreased, gas in the compression chamber 54 is compressed.
[0003] A compression reaction force generated by compressing gas
acts on the rear face 55a of the front housing part 55. Guide holes
55b (only one is shown) are formed in the rear face 55a. Support
holes 53b are formed in a base plate 53a of the movable scroll 53.
A pin 57 is fitted in each support hole 53b. The distal end of each
pin 57 is inserted into the corresponding guide hole 55b. Each pin
57, the corresponding hole 53b and the corresponding guide hole 55b
form an anti-rotation mechanism. When rotation of the drive shaft
56 is transferred to the movable scroll 53 by the crank mechanism
56a, the anti-rotation mechanisms prevent the movable scroll 53
from rotating, while permitting the movable scroll 53 to orbit at a
predetermined radius.
[0004] The diameter of the support holes 53b is slightly greater
than the diameter of the pins 57 such that each pin 57 rotates in
the corresponding support hole 53b. The pins 57 are supported by
the movable scroll 53 in a cantilevered manner. Therefore, when
receiving a radial force, each pin 57 is slightly inclined in the
corresponding hole 53b. When the movable scroll 53 is orbiting,
inclination of the pins 57 causes the load to concentrate at the
open end of the hole 53b, which excessively wears the open end of
the hole 53b. The wearing of the open end of the holes 53b causes
the inclination of the pins 57 to increase. As a result, the orbit
radius of the movable scroll 53 eventually exceeds the initial
value. A greater orbit radius of the scroll 53 degrades the
compression efficiency of the compressor. If the pins 57 are
supported by the front housing part 55 and the guide holes are
formed in the base plate 53a, the compressor will have the same
problem.
[0005] In order to prevent the pin 57 from inclining, the proximal
end of each pin 57 may be fixed within the corresponding support
hole 53b, and a bearing may be fitted to the distal end of each pin
57. The outer surface of the bearing rolls on the wall of the guide
hole 55b. This structure prevents the pins 57 from inclining
relative to the movable scroll 53. Thus, the holes 53b are not
unevenly worn. However, when the compressor is started, the movable
scroll 53 is slightly inclined. At this time, each bearing unevenly
contacts the open end of the corresponding guide hole 55b. This
unevenly wears the bearings and the open end of the guide holes
55b, which eventually increases the orbit radius of the movable
scroll 53. Accordingly, the compression efficiency of the
compressor is lowered.
SUMMARY OF THE INVENTION
[0006] Accordingly, it is an objective of the present invention to
provide a scroll compressor that improves the compression
efficiency.
[0007] To achieve the foregoing and other objectives and in
accordance with the purpose of the present invention, a scroll
compressor for compressing gas is provided. The scroll compressor
includes a housing having an annular groove that includes a pair of
walls facing each other, a fixed scroll formed in the housing, a
drive shaft rotatably supported in the housing, a movable scroll
accommodated in the housing to mate with the fixed scroll and a
crank mechanism. The crank mechanism is located between the drive
shaft and the movable scroll for driving the movable scroll in
accordance with the rotation of the drive shaft. A projection
extends radially from the movable scroll along a plane
perpendicular to the axis of the drive shaft. The projection is
located in the annular groove and slides along the walls of the
annular groove, and has a thickness measured in the axial direction
of the drive shaft. The distance between the groove walls is
greater than the thickness of the projection by a predetermined
value. The scroll compressor further includes a restriction
mechanism for inhibiting rotation of the movable scroll with
respect to the axis of the movable scroll and for permitting
orbital movement of the movable scroll. The restriction mechanism
includes a restriction member supported by the projection or the
groove walls.
[0008] Other aspects and advantages of the invention will become
apparent from the following description, taken in conjunction with
the accompanying drawings, illustrating by way of example the
principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The features of the present invention that are believed to
be novel are set forth with particularity in the appended claims.
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:
[0010] FIG. 1 is a cross-sectional view showing a scroll compressor
according to a first embodiment of the present invention;
[0011] FIG. 2 is an exploded perspective view showing the
compressor of FIG. 1;
[0012] FIG. 3 is an enlarged partial cross-sectional view
illustrating an anti-rotation mechanism;
[0013] FIG. 4 is a cross-sectional view taken along line 4-4 of
FIG. 1;
[0014] FIG. 5 is an enlarged partial cross-sectional view
illustrating a an anti-rotation mechanism according to a second
embodiment;
[0015] FIG. 6 is an enlarged partial cross-sectional view
illustrating a an anti-rotation mechanism according to a third
embodiment;
[0016] FIG. 7 is an enlarged partial cross-sectional view
illustrating a an anti-rotation mechanism according to a fourth
embodiment;
[0017] FIG. 8 is an enlarged partial cross-sectional view
illustrating a an anti-rotation mechanism according to a fifth
embodiment;
[0018] FIG. 9 is a perspective view showing a movable scroll
according to another embodiment; and
[0019] FIG. 10 is a cross-sectional view illustrating a prior art
scroll compressor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] A scroll compressor according to a first embodiment of the
present invention will now be described with reference to FIGS. 1
to 4.
[0021] As shown in FIG. 1, the scroll compressor includes a center
housing part 11, a front housing part 12 and a rear housing part
13, which are made of aluminum alloy. The center housing part 11,
the front housing part 12 and the rear housing part 13 are secured
to one another by bolts (not shown). As shown in FIG. 2, a recess
122 is formed in the front housing part 12. A rim 111 is formed in
the front end (left side as viewed in FIG. 1) of the center housing
part 11. A rim 121 is formed in the rear end (right side as viewed
in FIG. 1) of the front housing part 12. The rim 111 is secured to
the rim 121. The rear housing part 13 is secured to the rear end of
the center housing part 11.
[0022] A fixed scroll 14 is integrally formed with the center
housing part 11 and includes a base plate 141 and a volute portion
142 protruding from the base plate 141. The front housing part 12
and the center housing part 11 accommodate a movable scroll 15. The
movable scroll 15 includes a base plate 151, a volute portion 152
protruding from the rear side of the base plate 151, a boss 153
protruding from the front side of the base plate 151 and a radial
projection, or flange 154. The flange 154 is integrally formed with
the periphery of the base plate 151 such that the flange 154 lies
in a plane perpendicular to the axis of the drive shaft 18. A
compression chamber 16 is defined between the volute portion 152 of
the movable scroll 15 and the volute portion 142 of the fixed
scroll 14. An annular suction chamber 17 is defined between the
volute portions 142, 152 and the inner wall of the center housing
part 11. A crank chamber 28 is defined between the front housing
part 12 and the base plate 151 of the movable scroll 15. A crank
mechanism 29 is accommodated in the crank chamber 28. The crank
mechanism 29 orbits the movable scroll 15.
[0023] As shown in FIG. 1, the drive shaft 18 is rotatably
supported by a bearing 19 in the front housing part 12. The crank
mechanism 29 includes the drive shaft 18, a crank pin 20, a bushing
21 and a counter weight 23. As shown in FIGS. 2 and 4, the crank
pin 20 extends rearward from the drive shaft 18 and is radially
offset from the axis of the drive shaft 18. The bushing 21 has an
eccentric hole 22. The bushing 21 is fitted in the boss 153 with a
bearing 24. The distal end of the crank pin 20 is fitted in the
eccentric hole 22. The counterweight 23 is integrally formed with
the proximal end of the crank pin 20.
[0024] The structure of the anti-rotation mechanisms 25 (only one
is shown) will now be described with reference to FIGS. 1 to 3. The
anti-rotation mechanisms 25 permit the movable scroll 15 to orbit
while prohibiting its rotation. As shown in FIG. 1, the recess 122
of the front housing part 12 and the front face 112 of the center
housing part 11 define an annular groove. The axial dimension of
the annular groove is slightly greater than that of the flange 154.
Most of the flange 154 is located in the groove.
[0025] As shown in FIG. 2, four support holes 155 extend through
the flange 154. The support holes 155 are equally spaced apart in
the circumferential direction of the flange 154. A pin 26 is
inserted in each support hole 155. The diameter of the pins 26 is
slightly smaller than that of the support holes 155 so that each
pin 26 is permitted to rotate. Four guide holes 113 are formed in
the front face 112 of the center housing part 11. As shown in FIGS.
1 and 3, another four guide holes 123 are formed in the recess 122.
Each pin 26 is loosely fitted in the corresponding pair of guide
holes 113 and 123.
[0026] As shown in FIG. 2, an annular spacer 27 is located between
the front end face 158 of the flange 154 and the front housing part
12. The compression reaction force acting on the movable scroll 15
is received by the front housing part 12 via the spacer 27. The
spacer 27 has four through holes 271. The pins 26 are inserted in
the through holes 271. The distance X (see FIG. 3) between the rear
end face 159 of the flange 154 and the front face 112 of the center
housing part 11 can be changed by altering the thickness of the
spacer 27. In the embodiment of FIGS. 1 to 4, the distance X is
0.01 mm.
[0027] As shown in FIG. 3, a recess 156 is formed about each
support hole 155 on each face 158, 159 of the flange 154. That is,
the support holes 155 are countersunk The recesses 156 facilitate
the entry of atomized oil, which is dispersed in the refrigerant
gas, into the support holes 155. When the drive shaft 18 rotates,
engagement of the pins 26 and the guide holes 113, 123 prevents the
movable scroll 15 from rotating while permitting the movable scroll
15 to orbit about the axis of the drive shaft 18. The orbit radius
of the movable scroll 15 is calculated by subtracting the radius of
the pin 26 from the radius of the guide holes 113, 123.
[0028] As shown in FIG. 1, an inlet 30 is formed in the front
housing part 12. The inlet 30 is connected to an external
refrigerant circuit (not shown). Refrigerant gas is drawn into the
crank chamber 28 through the inlet 30. As shown in FIGS. 1 and 2,
suction passages 157 are formed in the flange 154 to conduct
refrigerant gas in the crank chamber 28 to the suction chamber 17.
A discharge port 31 is formed in the center of the base plate 141
of the fixed scroll 14 to communicate the compression chamber 16
with a discharge chamber 32 formed in the rear housing part 13. A
discharge valve flap 33 is located at the outer end of the
discharge port 31. A stopper 34 limits the opening amount of the
discharge valve flap 33. An outlet 35 is formed in the rear housing
part 13. Pressurized gas in the discharge chamber 32 is discharged
to the external refrigerant circuit through the outlet 35.
[0029] The operation of the scroll compressor will now be
described.
[0030] When the drive shaft 18 is rotated, the crank pin 20, the
bushing 21 and the bearing 24 causes the movable scroll 15 to orbit
about the axis of the drive shaft 18 without rotating the scroll
15. Orbital movement of the scroll 15 draws refrigerant gas into
the suction chamber 17 through the inlet 30, the crank chamber 28
and the suction passage 157. The refrigerant gas flows from the
suction chamber 17 to the compression chamber 16 along the volute
portions 142, 152. The orbiting movement of the movable scroll 15
moves the gas along the volute portions 142, 152 toward the center
of the compression chamber 16, while gradually compressing the gas.
The compressed gas pushes open the discharge valve flap 33 and
flows into the discharge chamber 32 through the discharge port 31.
The gas is then supplied to the external refrigerant circuit
through the outlet 35.
[0031] The scroll compressor of FIGS. 1 to 4 has the following
advantages.
[0032] (1) The flange 154 formed on the movable scroll 15 lies in a
plane perpendicular to the axis of the drive shaft 18. The flange
154 is located between the center housing part 11 and the front
housing part 12, and the distance X exists between the flange 154
and the center housing part 11. The mid-section of each pin 26
engages the flange 154, and the ends of each pin 26 are loosely
fitted in the corresponding guide holes 113, 123. This construction
permits the movable scroll 15 to orbit without rotating. When the
movable scroll 15 is orbiting, the forces act evenly on the parts
of each pin 26 that engage the guide holes 113, which prevents the
open ends of the corresponding support hole 155 from being worn
excessively. As a result, the orbit radius of the movable scroll 15
is not increased and the compression efficiency of the compressor
is not lowered. The durability of the compressor is also
improved.
[0033] (2) The compression reaction force urges the flange 154 to
the left as viewed in FIG. 3, which creates a space between the
rear end face 159 of the flange 154 and the front face 112 of the
center housing part 11. However, the spacer 27 maintains the space
X between the rear face 159 of the flange 154 and the front face
112 of the center housing part 11 at a relatively narrow dimension
(0.01 mm). This prevents the movable scroll 15 from being inclined,
particularly when the movable scroll 15 starts orbiting. As a
result, the movable scroll 15 is started smoothly and operates
smoothly thereafter.
[0034] (3) Dimensional tolerances in measurement and assebly of the
compressor cause the distance X to vary. The variations of the
distance X result in variations of characteristics of manufactured
compressors. However, the variations of the distance X are
compensated for by simply changing the thickness of the spacer 27,
which is located between the recess 122 and the flange 154.
Accordingly, variations of characteristics of manufactured
compressors are eliminated. The spacer 27 may be made of a material
having a high wear resistance such as stainless steel, and the
flange 154 may be made of aluminum alloy. This prevents engaging
surfaces of the spacer 27 and the flange 154 from being easily
worn, thereby improving the durability of the compressor.
[0035] (4) The recesses 156 are formed about the ends of each
support hole 155. The recesses 156 allow refrigerant gas containing
atomized oil to easily enter between the support hole 155 and the
pin 26. As a result, the pin 26 smoothly slides on the inner wall
of the support hole 155, which prevents the pin 26 and the support
hole 155 from wearing.
[0036] (5) The flange 154 is integrally formed with the movable
scroll 15, which facilitates the manufacture.
[0037] A scroll compressor according to a second embodiment will
now be described with reference to FIG. 5. The differences from the
embodiment of FIGS. 1 to 4 will mainly be discussed below.
[0038] In the second embodiment, front support holes 12a are formed
in the front housing part 12 and corresponding rear support holes
11a are formed in the center housing part 11. Guide holes 15a are
formed in the movable scroll 15. Each pin 26 extends through one of
the guide holes 15a and is supported by the corresponding front and
rear support holes 12a, 11a. Therefore, the axial center of each
pin 26 engages the wall of the associated guide hole 15a, and the
ends of each pin 26 are supported by the corresponding support
holes 11a, 12a. The diameter of each guide hole 15a is greater than
the diameter of the pins 26. The orbit path of the movable scroll
15 is defined by contact between the guide pins 26 and the guide
holes 15a.
[0039] The construction of FIG. 5 prevents the pins 26 from
inclining when the movable scroll 15 orbits. Therefore, neither the
support holes 11a, 12a nor the guide holes 15a are worn near their
openings, which prevents the orbit radius of the movable scroll 15
from increasing. As a result, the compression efficiency of the
compressor will not degrade. Further, the construction of FIG. 5
smoothly orbits the movable scroll 15. The embodiment of FIG. 5 has
the advantages (2) to (5) of the embodiment of FIGS. 1 to 4.
[0040] A scroll compressor according to a third embodiment will now
be described with reference to FIG. 6. The differences from the
embodiment of FIGS. 1 to 4 will mainly be discussed below. In the
embodiment of FIG. 6, anti-rotation mechanisms 25 (only one is
shown) are located between the front housing part 12 and the center
housing part 11. The construction of the anti-rotation mechanism 25
of FIG. 6 is similar to that of a ball bearing. The mechanism 25
includes a flange 154, a support hole 15b, a ball 41 and guide
holes 11b, 12b. The support hole 15b is formed in the flange 154
for rotatably accommodating the ball 41. The ball 41 is located
between the guide hole 11b formed in the center housing part 11 and
the guide hole 12b formed in the front housing part 12. The guide
holes 11b, 12b have concave surfaces corresponding to the shape of
the ball 41. The mid-section of the ball 41 is supported by the
flange 154, while the ends of the ball 41 engage the guide holes
11b, 12b.
[0041] When the movable scroll 15 orbits, forces act evenly on the
walls of the guide holes 11b, 12b via the ball 41. This prevents
the support hole 15b and guide holes 11b, 12b from being unevenly
worn. Further, the embodiment of FIG. 5 has the advantages (2) to
(5) of the embodiment of FIGS. 1 to 4.
[0042] A scroll compressor according to a fourth embodiment will
now be described with reference to FIG. 7. The differences from the
embodiment of FIGS. 1 to 4 will mainly be discussed below. In the
embodiment of FIG. 7, the rear guide holes 113 shown in FIGS. 1 to
4 are omitted. Blind support holes 15c are formed in the flange
154. One end of each pin 26 is inserted in one of the support holes
15c. The other end of the pin 26 is inserted into the guide hole
123. The outer surface of each pin 26 is parallel to the wall of
the corresponding guide hole 123. The distance X between the front
face 112 of the rim 111 and the flange 154 is 0.01 mm, as in the
embodiment of FIGS. 1 to 4. Therefore, the flange 154, which is
located between the housings 11, 12, lies in a plane perpendicular
to the drive shaft 18. The movable scroll 15 is prevented from
inclining relative to the plane.
[0043] The construction of FIG. 7 prevents the flange 154 (the
movable scroll 15) from inclining when the movable scroll 15
orbits. Thus, the pins 26 are not inclined relative to the inner
surface of the guide holes 123. Therefore, the construction of FIG.
7 prevents the support holes 15c and the guide holes 123 from being
unevenly worn. As a result, the orbit radius of the movable scroll
15 is not increased and the compression efficiency does not
degrade. Further, the construction of FIG. 7 allows the movable
scroll 15 to smoothly orbit. Also, the embodiment of FIG. 7 has the
advantages (3) to (5) of the embodiment of FIGS. 1 to 4.
[0044] A scroll compressor according to a fifth embodiment will now
be described with reference to FIG. 8. The differences from the
embodiment of FIG. 5 will mainly be discussed below. In the
embodiment of FIG. 8, the rear support holes 11a shown in FIG. 5
are omitted. Each pin 26 is supported by a support hole 124 formed
in the front housing part 12. The outer surface of each pin 26 is
parallel to the inner surface of the corresponding guide hole 15a.
The distance X between the front face 112 of the rim 111 and the
flange 154 is 0.01 mm, as in the embodiment of FIGS. 1 to 4.
Therefore, the flange 154, which is located between the housings
11, 12, lies in a plane perpendicular to the drive shaft 18. The
movable scroll 15 is prevented from inclining relative to the
plane.
[0045] The construction of FIG. 8 prevents the flange 154 (the
movable scroll 15) from inclining when the movable scroll 15
orbits. Therefore, each support hole 124 and each guide hole 15a
are prevented from being unevenly worn. As a result, the orbit
radius of the movable scroll 15 is not increased, and the
compression efficiency is not lowered. Further, the construction of
FIG. 8 allows the movable scroll 15 to smoothly orbit.
[0046] The embodiment of FIG. 8 has the advantages (3) to (5) of
the embodiment of FIGS. 1 to 4.
[0047] Although only five embodiments of the present invention have
been described herein, 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 invention
may be embodied in the following forms.
[0048] In the embodiment of FIGS. 1 to 4, each pins 26 may be fixed
to the flange 154 and bearings may be fitted to the ends of the pin
26. The bearings roll along the walls of the guide holes 113, 123.
This construction prevents the pin 26 from inclining relative to
the inner surfaces of the guide holes 113, 123. Therefore, uneven
wear of the guide pins 26 and the guide holes 113, 123 is
prevented.
[0049] In the embodiment of FIG. 5, bearings may be located between
the outer surface of each pin 26 and the inner surfaces of the
support holes 11a, 12a. Alternatively, a bearing may be located
between each guide pin 26 and the corresponding guide hole 15a.
[0050] The shape of the flange 154 may be altered. For example, as
shown in FIG. 9, the flange 154 may be replaced by projections 154a
extending radially from the base plate 151 of the movable scroll
15.
[0051] The flange 154 may be made of material different from that
of the base plate 151. In this case, the flange 154 may be
integrated with the base plate 151 by insert molding.
[0052] The distance X may be changed between 0.01 m and 0.2 mm.
[0053] The number of the anti-rotation mechanisms 25 may be
arbitrarily determined.
[0054] Therefore, 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.
* * * * *