U.S. patent application number 14/593294 was filed with the patent office on 2015-07-16 for scroll type compressor.
This patent application is currently assigned to KABUSHIKI KAISHA TOYOTA JIDOSHOKKI. The applicant listed for this patent is KABUSHIKI KAISHA TOKYO JIDOSHOKKI. Invention is credited to Tatsushi MORI, Kosaku TOZAWA.
Application Number | 20150198161 14/593294 |
Document ID | / |
Family ID | 53520966 |
Filed Date | 2015-07-16 |
United States Patent
Application |
20150198161 |
Kind Code |
A1 |
TOZAWA; Kosaku ; et
al. |
July 16, 2015 |
SCROLL TYPE COMPRESSOR
Abstract
A scroll type compressor includes a housing, a rotary shaft
rotatably supported in the housing and having an eccentric pin
projecting from an end of the rotary shaft, a fixed scroll member
and a movable scroll member facing the fixed scroll and forming a
pair of compression chambers therewith. The scroll type compressor
further includes a balancer-integrated bush having an eccentric
hole to receive the eccentric pin and disposed between the
eccentric pin and the movable scroll. The balancer-integrated bush
is configured to receive rotational force from the rotary shaft to
cause the movable scroll member to make an orbital movement. An
elastic member provided between the rotary shaft and the
balancer-integrated bush in an elastically deformed state to always
apply a preload to the movable scroll member via the
balancer-integrated bush in a direction that increases an orbital
radius of the movable scroll member.
Inventors: |
TOZAWA; Kosaku; (Aichi-ken,
JP) ; MORI; Tatsushi; (Aichi-ken, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KABUSHIKI KAISHA TOKYO JIDOSHOKKI |
Kariya-shi |
|
JP |
|
|
Assignee: |
KABUSHIKI KAISHA TOYOTA
JIDOSHOKKI
Kariya-shi
JP
|
Family ID: |
53520966 |
Appl. No.: |
14/593294 |
Filed: |
January 9, 2015 |
Current U.S.
Class: |
418/55.3 |
Current CPC
Class: |
F04C 2240/807 20130101;
F04C 2240/60 20130101; F04C 29/0057 20130101; F04C 18/0215
20130101; F04C 29/0021 20130101 |
International
Class: |
F04C 29/00 20060101
F04C029/00; F04C 18/02 20060101 F04C018/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 15, 2014 |
JP |
2014-005213 |
Claims
1. A scroll type compressor comprising: a housing; a rotary shaft
rotatably supported in the housing; an eccentric pin projecting
axially from an end surface of the rotary shaft; a fixed scroll
member fixed to the housing; a movable scroll member facing the
fixed scroll and forming a compression chamber therewith; a
balancer-integrated bush having an eccentric hole to receive the
eccentric pin and disposed between the eccentric pin and the
movable scroll, the balancer-integrated bush being configured to
receive rotational force from the rotary shaft to cause the movable
scroll member to make an orbital movement; and an elastic member
provided between the rotary shaft and the balancer-integrated bush
in an elastically deformed state to always apply a preload to the
movable scroll member via the balancer-integrated bush in a
direction that increases an orbital radius of the movable scroll
member.
2. The scroll type compressor according to claim 1, wherein the
balancer-integrated bush has a first surface facing the end surface
of the rotary shaft, wherein the end surface is provided with a
first shaft recess and the first surface is provided with a first
bush recess, wherein the first shaft recess and the first bush
recess cooperate to receive the elastic member.
3. The scroll type compressor according to claim 1, wherein the
balancer-integrated bush has a second surface facing an outer
peripheral surface of the rotary shaft, wherein the outer
peripheral surface is provided with a second shaft recess and/or
the second surface is provided with a second bush recess, wherein
at least one of the second shaft recess and the second bush recess
receives the elastic member.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a scroll type
compressor.
[0002] A scroll type compressor employs a link mechanism such as a
swing link mechanism and a slide link mechanism. The Patent
Application Publication No. 2009-127524 discloses a swing link
mechanism of a scroll type compressor. These link mechanisms enable
to vary the orbital radius of the movable scroll member of the
scroll type compressor. Even if any scroll member has a machining
tolerance or an assembly tolerance, the scroll members can be set
in contact with each other with an appropriate contact pressure. In
addition, the movable scroll member having a variable orbital
radius can protect the wrap surface of the scroll members against
any foreign matter between the scroll members.
[0003] With a scroll type compressor having a mechanism for the
variable orbital radius of the movable scroll member, noise is
likely to be generated by a collision between a rotary shaft and a
bush during the starting and stopping of the compressor.
[0004] The present invention, which has been made in light of the
problems mentioned above, is directed to providing a scroll type
compressor which can reduce the noise generated during the
operation or stopping of the compressor.
SUMMARY OF THE INVENTION
[0005] In accordance with an aspect of the present invention, there
is provided a scroll type compressor including a housing, a rotary
shaft rotatably supported in the housing and having an eccentric
pin projecting from an end of the rotary shaft, a fixed scroll
member and a movable scroll member facing the fixed scroll and
forming a pair of compression chambers therewith. The scroll type
compressor further includes a balancer-integrated bush having an
eccentric hole to receive the eccentric pin and disposed between
the eccentric pin and the movable scroll. The balancer-integrated
bush is configured to receive rotational force from the rotary
shaft to cause the movable scroll member to make an orbital
movement. An elastic member provided between the rotary shaft and
the balancer-integrated bush in an elastically deformed state to
always apply a preload to the movable scroll member via the
balancer-integrated bush in a direction that increases an orbital
radius of the movable scroll member.
[0006] 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
[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 longitudinal sectional view showing an overall
configuration of a compressor according to a first embodiment;
[0009] FIG. 2 is a plan view of a balancer-integrated bush provided
in the compressor of FIG. 1, as viewed from electric motor side of
the compressor;
[0010] FIG. 3 is a cross-sectional view of a rotary shaft, the
balancer-integrated bush and an elastic member provided in the
compressor of FIG. 1;
[0011] FIG. 4 is an exploded perspective view of the rotary shaft,
the balancer-integrated bush and the elastic member of the
compressor of FIG. 1;
[0012] FIG. 5 is a plan view of a movable scroll wrap of a movable
scroll member and a fixed scroll wrap of a fixed scroll member of
the compressor of FIG. 1;
[0013] FIG. 6 is a first plan view showing a dimensional relation
of the rotary shaft and the balancer-integrated bush of the
compressor of FIG. 1;
[0014] FIG. 7 is a second plan view showing another dimensional
relation of the rotary shaft and the balancer-integrated bush of
the compressor of FIG. 1;
[0015] FIG. 8 is a third plan view showing still another
dimensional relation of the rotary shaft and the
balancer-integrated bush of the compressor of FIG. 1;
[0016] FIG. 9 is a cross-sectional view of the rotary shaft, the
balancer-integrated bush and the elastic member of a compressor in
a comparative example;
[0017] FIG. 10 is a plan view of the rotary shaft, the
balancer-integrated bush and the elastic member of a compressor
according to a comparative example;
[0018] FIG. 11 is a plan view of the movable scroll wrap of the
movable scroll member and the fixed scroll wrap of the fixed scroll
member of the compressor according to a comparative example;
[0019] FIG. 12 is a perspective view of the rotary shaft, the
balancer-integrated bush and the elastic member of a compressor
according to a second embodiment.
[0020] FIG. 13 is a plan view of the rotary shaft, the
balancer-integrated bush and the elastic member of the compressor
of FIG. 12; and
[0021] FIG. 14 is a perspective view of the rotary shaft and the
elastic member of the compressor of FIG. 12.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0022] The following will described embodiments of the present
invention with reference to the accompanying drawings. The number
or quantity of any part or element appearing in the following
description, unless otherwise mentioned, may not be construed to
limit the scope of the present invention. Identical or
corresponding parts or elements will be denoted by the same
reference numeral and the description thereof may be omitted if
found redundant.
[0023] Referring to FIG. 1 showing a scroll type compressor 100 of
a first embodiment in longitudinal sectional view (hereinafter
simply referred to as compressor), the compressor 100 includes a
housing 10, a compression mechanism 20, an electric motor 30 and a
rotary shaft 40. The housing 10 includes a motor housing 11, an
inner housing 12 and a discharge housing 13. These housings are
made of a metal material such as an aluminum alloy.
[0024] The motor housing 11 has a bottomed cylindrical shape and a
suction port (not shown) is formed through the side wall of the
motor housing 11. The motor housing 11 has at the bottom thereof a
bearing 41A that rotatably supports the rotary shaft 40 at one end
thereof on the front side of the compressor 100. Numeral 41
designate an end surface of the rotary shaft 40 at the front end. A
cover 14 is mounted to the bottom of the motor housing 11. A motor
driving circuit 15A is disposed in a space 14A formed between the
motor housing 11 and the cover 14.
[0025] The inner housing 12 is accommodated in the motor housing
11. The inner housing 12 includes a projection 12A having formed
therein a recess 12B. A bearing 42A is provided in the projection
12A of the inner housing 12 and rotatably supports the other end of
the rotary shaft 40 on the rear side of the compressor 100. Numeral
42 designates an end surface of the rotary shaft at the rear end.
Thus, the rotary shaft 40 is rotatably supported at the opposite
ends thereof by the bearing 41A and 42A. As will be described in
details later, a balancer-integrated bush 60 is disposed in the
recess 12B and an elastic member 70 is provided between the rotary
shaft 40 and the balancer-integrated bush 60.
[0026] The discharge housing 13 has a bottomed cylindrical shape
and is connected to the motor housing 11 so as to close the rear
end of the motor housing 11. An outlet port 13B is formed through
the discharge housing 13. A discharge chamber 13A is formed between
the compression mechanism 20 and the discharge housing 13. The
discharge chamber 13A is in communication with an external
refrigeration circuit through the outlet port 13B.
[0027] The compression mechanism 20 includes a movable scroll
member 21 and a fixed scroll member 22 that are disposed in facing
relation to each other. The compression mechanism 20 is disposed
adjacent to the end surface 42 of the rotary shaft 40. The movable
scroll member 21 includes an end plate 21A and a spiral-shaped
movable scroll wrap 21B that extends from the end plate 21A. The
fixed scroll member 22 is fixed to the motor housing 11 and
includes an end plate 22A and a spiral-shaped fixed scroll wrap 22B
that extends from the end plate 22A. A discharge port 23A is formed
through the end plate 22A of the fixed scroll member 22 in
communication with the discharge chamber 13A. A compression chamber
20A is formed between the movable scroll member 21 and the fixed
scroll member 22 by engagement of the fixed scroll wrap 22B with
the movable scroll wrap 21B.
[0028] The discharge port 23A is formed between the compression
chamber 20A and the discharge chamber 13A thereby to provide a
fluid communication therebetween. A discharge valve 50 which opens
or closes the discharge port 23A is provided on the discharge port
23A on the side facing the discharge chamber 13A. When refrigerant
gas drawn into the compression chamber 20A is compressed there, the
compressed refrigerant gas pushes open the discharge valve 50 and
is discharged into the discharge chamber 13A through the discharge
port 23A.
[0029] The electric motor 30 includes a stator coil 31 and a rotor
32, and the electric motor 30 is disposed adjacent to the end
surface 41 of the rotary shaft 40. The stator coil 31 is disposed
on the outer periphery of the rotor 32. The rotor 32 is fixed to
the rotary shaft 40 and rotated integrally. A coil wire of the
electric motor 30 is connected to a motor driving circuit 15A via a
lead wire 15D, a cluster block 15C and a terminal 15B. The motor
driving circuit 15A drives the electric motor 30, and the rotary
shaft 40 is rotated, accordingly.
[0030] An eccentric pin 43 is formed extending from the end surface
42 of the rotary shaft 40. The eccentric pin 43 is disposed
eccentrically with respect to the axis of the rotary shaft 40. The
eccentric pin 43 extends towards the compression mechanism 20 in
axial direction of the rotary shaft 40. The aforementioned
balancer-integrated bush 60 is revolvably mounted on the eccentric
pin 43 and revolvable between the eccentric pin 43 and the movable
scroll member 21 by receiving rotational force from the rotary
shaft 40 via the eccentric pin 43.
[0031] The balancer-integrated bush 60 includes a bush 62 and a
balancer 65. The movable scroll member 21 is rotatably mounted on
the bush 62 via a bearing 45A. When the rotary shaft 40 rotates,
the bush 62 is revolved about the eccentric pin 43 and the movable
scroll member 21 makes an orbital movement by virtue of the
eccentric pin 43 and the bush 62. Because the movable scroll member
21 is prevented from rotating on its own axis by anti-rotation
mechanism 21C, the movable scroll member 21 orbits relative to the
fixed scroll member 22.
[0032] The line contact portion between the movable scroll wrap 21B
of the movable scroll member 21 and the fixed scroll wrap 22B of
the fixed scroll member 22 is moved gradually towards the center of
the scroll members 21, 22. Accordingly, the compression chamber 20A
moves toward the center while reducing the volume thereof.
Therefore the refrigerant gas drawn into the compression chamber
20A through the suction port (not shown) is moved toward the
discharge port 23A formed at the center of the end plate 22A of the
fixed scroll member 22, while being compressed. The, compressed
refrigerant gas pushes open the discharge valve 50 at the discharge
port 23A and is discharged into the discharge chamber 13A. Then,
the refrigerant gas is discharged out to the external refrigeration
circuit through the outlet port 13B.
[0033] The balancer-integrated bush 60 will be described in detail
with reference to FIGS. 2 to 8. FIG. 2 is a plan view of the
balancer-integrated bush 60 in the compressor 100 as viewed from
the electric motor 30 side. For the convenience of the description,
the rotary shaft 40 is shown by a chain double-dashed line and the
elastic member 70 formed between the rotary shaft 40 and the
balancer-integrated bush 60 is shown by a dotted line in FIG. 2.
FIG. 3 is a cross-sectional view of the rotary shaft 40, the
balancer-integrated bush 60 and the elastic member 70. FIG. 4 is an
exploded perspective view of the rotary shaft 40, the
balancer-integrated bush 60 and the elastic member 70.
[0034] As shown in FIGS. 2 to 4, the balancer-integrated bush 60
includes the bush 62 and the balancer 65. The bush 62 and the
balancer 65 are formed integrally. Referring to FIG. 2, the
balancer-integrated bush 60 shown in plan view is shaped
substantially symmetrical with respect to an axial line CL shown by
dashed line. An eccentric hole 64 is formed in the bush 62 of the
balancer-integrated bush 60 with the axial center C64 of the
eccentric hole 64 offset from the axial center of the bush 62.
[0035] The bush 62 has a cylindrical shape and the movable scroll
member 21 is rotatably mounted on the bush 62 via the bearing 45A
(FIG. 1). The eccentric hole 64 is formed in the bush 62 on the
side thereof that faces the end surface 42 of the rotary shaft 40.
The eccentric hole 64 is formed eccentrically with respect to the
axial center C62 of the bush 62.
[0036] The eccentric pin 43 is formed extending from the end of the
rotary shaft 40 (FIGS. 3, 4). The end surface 42 of the rotary
shaft 40, which is shown by a chain double-dashed line in FIG. 2,
has a circle shape with a radius R40 with axis C40 as a center. The
eccentric pin 43 is disposed eccentrically with respect to the axis
C40 of the rotary shaft 40. The end of the eccentric pin 43 is
inserted in the eccentric hole 64 so that balancer-integrated bush
60 mounted on the eccentric pin 43. The axial dimension of the
eccentric pin 43 is larger than the depth of the eccentric hole 64,
so that part of the eccentric pin 43 which is adjacent to the end
surface 42 of the rotary shaft 40 is exposed when the eccentric pin
43 is inserted into the eccentric hole 64 (Refer to FIG. 3).
[0037] The balancer 65 is formed closer to the rotary shaft 40 than
the bush 62 in the axial direction of the rotary shaft 40. The
balancer 65 has a plate-like shape in a side view and has a fan
shape in plan view.
[0038] The balancer 65 includes a main body 65B and a projecting
portion 65A. The projecting portion 65A is formed only on the outer
periphery of the balancer 65. The projecting portion 65A extends in
axial direction towards the rotary shaft 40 parallel to the rotary
shaft 40.
[0039] The balancer 65 has a concave circular surface 66 facing the
outer peripheral surface of the eccentric pin 43, a flat surface 67
extending perpendicularly to the surface 66, a concave circular
surface 68 extending perpendicularly to the surface 67 in the axial
direction of the rotary shaft 40 and a flat surface 69 extending
perpendicularly to the surface 68. The surface 66 extends parallel
to the axis C40 of the rotary shaft 40 (FIG. 2). The surface 67
faces the end surface 42 of the rotary shaft 40. The surface 67
corresponds to a first surface of the present invention. The
surfaces 66 and 67 form a part of the surface of the main body 65B,
respectively. A clearance is formed between the surface 67 and the
end surface 42 of the rotary shaft 40. A fitting hole 67A is formed
in the main body 65B of the balancer 65 to open in the surface 67
and one end of the elastic member 70 is fitted in the fitting hole
67A.
[0040] The surface 68 faces the outer periphery of the rotary shaft
40. A clearance is formed between the surface 68 and the outer
periphery of the rotary shaft 40. The surface 68 is curved in a
complementary relation to the outer peripheral surface of the
rotary shaft 40. In other words, the surface 67 and the surface 68
cooperate to form a recess 61 (FIG. 3) that receives therein the
rear end of the rotary shaft 40. The surface 69 is formed only on
the outer periphery of the fan-shaped balancer 65. The surfaces 68
and 69 form a part of the surface of the projecting portion 65A,
respectively.
[0041] Referring to the FIG. 2, the point C65 is the center of an
arc having a radius R69 and forming a part of the fan shape of the
balancer 65. The point C65 is also the center of an arc having a
radius R68 and forming a part of a fan shape having the same center
angle as the fan shape of the balancer 65. The shape of the surface
69 substantially corresponds to a fan shape that may be formed by
removing the fan shape with the radius R68 from the fan shape with
radius R69.
[0042] A fitting hole 42B is formed in the rotary shaft 40 and the
other end of the elastic member 70 is fitted in the fitting hole
42B. The elastic member 70 has a cylindrical shape. The inner
diameters of the fitting hole 42B formed in the rotary shaft 40 and
the fitting hole 67A formed in the balancer-integrated bush 60 are
substantially the same as the outer diameter of the elastic member
70 and the elastic member 70 is press-fitted in these fitting holes
42B, 67A. The fitting holes 42B, 67A correspond to a first shaft
recess and a first bush recess, respectively, of the present
invention.
[0043] The fitting hole 42B and the fitting hole 67A are formed at
such positions that, when the elastic member 70 is fitted in the
holes, the balancer-integrated bush 60 is rotatable relative to the
rotary shaft 40 in the direction indicated by arrow DR2 in FIG. 2.
For example, the fitting hole 67A is disposed on the left side to
the axial line CL and the fitting hole 42B is disposed on the right
side thereto as seen in FIG. 2. Press-fitting the elastic member 70
in the fitting holes 42B, 67A, the balancer-integrated bush 60 is
urged so as to revolve about the eccentric pin 43 relative to the
rotary shaft 40 in the direction of the arrow DR2.
[0044] Arrow DR1 in FIG. 2 shows the direction in which the rotary
shaft 40 is driven to rotate by the electric motor 30 (FIG. 1). As
mentioned above, the movable scroll member 21 (FIG. 1) is mounted
orbitably on the bush 62 of the balancer-integrated bush 60 via the
bearing 45A (FIG. 1). When the rotary shaft 40 rotates, the
balancer-integrated bush 60 (bush 62) is revolved around the
eccentric pin 43, and the movable scroll member 21 orbits through
the eccentric pin 43 and the bush 62. In this case, the
anti-rotation mechanism 21C (FIG. 1) prevents the rotation of the
movable scroll 21 member.
[0045] The arrow direction DR2 is opposite to the arrow direction
DR1 (the rotational direction of the rotary shaft 40). When the
balancer-integrated bush 60 (bush 62) is revolved around the
eccentric pin in the arrow direction DR2 relative to the rotary
shaft 40, the movable scroll member 21 (bush 62) makes an orbiting
movement with a large radius. When the balancer-integrated bush 60
is revolved around the eccentric pin 43 in the arrow direction DR 1
relative to the rotary shaft 40, on the other hand, the movable
scroll member 21 makes an orbiting movement with a small
radius.
[0046] In the present embodiment, a preload is always applied to
the movable scroll member 21 via the balancer-integrated bush 60 in
the direction that increases the orbital radius of the movable
scroll member 21 by virtue of the elastic member 70 provided
between the end surface 42 of the rotary shaft 40 and the surface
67 of the balancer-integrated bush 60 in an elastically deformed
state. For the convenience of the explanation, the outer peripheral
of the rotary shaft 40 and the surface 68 of the
balancer-integrated bush 60 are shown spaced apart from each other
in FIG. 2. In actuality, the outer periphery of the rotary shaft 40
and the surface 68 of the balancer-integrated bush 60 are pressed
against each other by the preload of the elastic member 70 in a
state shown in FIG. 8.
[0047] The elastic member 70 is made of a resin or a rubber that is
compatible with the refrigerant and the lubricant used in the
compressor 100. For example, HNBR, NBR and EPDM may be used for the
elastic member 70. According to the present invention, however, any
material that has above compatibility may be used. If adequate
preload cannot be obtain due to the material or the shape of the
elastic member 70, any suitable metal may be used as a center core
to increase the rigidity of the elastic member 70.
[0048] Referring to FIG. 5 showing the movable scroll wrap 21B of
the movable scroll member 21 and the fixed scroll wrap 22B of the
fixed scroll member 22 in plan view, the movable scroll wrap 21B is
always urged so as to increase the orbital radius due to the
preload of the elastic member 70. In the state shown in FIG. 5, the
movable scroll wrap 21B is in contact with the fixed scroll wrap
22B at an appropriate contact pressure at a point P.
[0049] Referring to FIGS. 6 to 8, other dimensional relations of
the rotary shaft 40 and the balancer-integrated bush 60 will be
described. For the convenience of the explanation, the fitting hole
42B (FIG. 2), the fitting hole 67A and the elastic member 70 are
omitted from illustration in FIGS. 6 to 8.
[0050] In this embodiment, L68A is the distance between the axial
center C64 of the eccentric hole 64 and the edge end 68A of the
surface 68 on the leading side thereof with respect to the arrow
moving direction DR2. L68B is the distance between the axial center
C64 of the eccentric hole 64 and the edge end 68B of the surface 68
on the leading side thereof with respect to the arrow moving
direction DR1. PLE is the distance between the axial center of the
eccentric pin 43 and the point PE that lies on the outer periphery
of the rotary shaft 40 and is located furthest from the axial
center of the eccentric pin 43 (or the axial center C43). The
distance PLE is greater than either of the distance L68A and
L68B.
[0051] Referring to FIGS. 6 and 7, if the balancer-integrated bush
60 is revolved about the eccentric pin 43 in the arrow direction
DR1 (AR1) relative to the rotary shaft 40, the orbiting angle of
the movable scroll member 21 is small. The rotation amount of the
balancer-integrated bush 60 is restricted by the contact of the
outer periphery of the rotary shaft 40 with the edge end 68A of the
surface 68 of the balancer-integrated bush 60.
[0052] Referring to FIGS. 6 and 8, the orbital angle of the movable
scroll member 21 increases when the balancer-integrated bush 60
revolves about the eccentric pin 43 in the arrow direction DR2
(AR2) relative to the rotary shaft 40. The revolution amount of the
balancer-integrated bush 60 is restricted by the contact of the
outer periphery of the rotary shaft 40 with the edge end 68B of the
surface 68 of the balancer-integrated bush 60.
[0053] In this embodiment, the position of the eccentric pin 43,
the position and the outer diameter of the rotary shaft 40 and the
position and the radius of curvature of the surface 68 are
established so as to fulfill the above dimensional relations and,
therefore, the upper limit and the lower limit of the variable
orbital radius of the movable scroll member 21 is restricted. The
balancer-integrated bush 60 is revolvable while allowing variation
of the orbiting radius of the movable scroll member 21 within the
above range of the upper and lower limits.
[0054] The elastic member 70 provided between the fitting hole 42B
of the rotary shaft 40 and the fitting hole 67A of the
balancer-integrated bush 60 applies a preload to the movable scroll
member 21 that causes the balancer-integrated bush 60 to revolve
about the eccentric pin 43 in the arrow direction DR2 (or in the
direction that increases the orbital radius of the movable scroll
member 21) by virtue of the elasticity of the elastic member 70.
The outer periphery of the rotary shaft 40 and the surface 68 of
the balancer-integrated bush 60 are pressed against each other by
the preload of the elastic member 70, so that the rotary shaft 40
and the balancer-integrated bush 60 are kept in the state shown in
FIG. 8.
[0055] When the rotation of the rotary shaft 40 is stopped, the
balancer-integrated bush 60 tends to continue to revolve in the
arrow direction DR1 by inertia. Unless any effective measures is
taken, the balancer-integrated bush 60 continues to revolve about
the eccentric pin 43 in the arrow direction DR1 and the surface 68
of the balancer-integrated bush 60 collides against the outer
periphery of the rotary shaft 40, thus generating an abnormal
noise.
[0056] In this embodiment, the revolution of the
balancer-integrated bush 60 in the arrow direction of DR1 by
inertia is prevented by the preload of the elastic member 70 or by
a load urging the balancer-integrated bush 60 to revolve in the
arrow direction of DR2. When the rotary shaft 40 is stopped, a load
is applied to keep the surface 68 of the balancer-integrated bush
60 and the outer periphery of the rotary shaft 40 to be in contact,
thereby preventing abnormal noise development.
[0057] FIGS. 9 and 10 are a cross-sectional view and a plan view,
respectively, showing the rotary shaft 40 and the
balancer-integrated bush 60 of a compressor 101 provided as a
comparative example. FIG. 11 is a plan view of the movable scroll
wrap 21B of the movable scroll member 21 and the fixed scroll wrap
22B of the fixed scroll member 22. The compressor 101 shown in FIG.
9 through 11 is not configured to utilize the preload of the
elastic member 70.
[0058] In the compressor 101 having no elastic member, the outer
periphery of the rotary shaft 40 and the surface 68 of the
balancer-integrated bush 60 tend to be separated easily, as shown
in FIG. 10, when the compressor 101 is stopped. In addition, while
the compressor 101 is in a stopped state, the movable scroll wrap
21B of the movable scroll member 21 and the fixed scroll wrap 22B
of the fixed scroll member 22 tend to be separated, as shown in
FIG. 11. When the compressor 101 is started in this state, the
surface 68 of the balancer-integrated bush 60 and the outer
periphery of the rotary shaft 40 collide against each other and
generate an abnormal noise. Specifically the compressor 101
generates noise when the state of the compressor 101 is changed
from FIG. 10 to FIG. 7.
[0059] The preload of the elastic member 70 is also effective when
the compressor 100 is started. In the compressor 100 of the present
embodiment, the outer periphery of the rotary shaft 40 and the
surface 68 of the balancer-integrated bush 60 are pressed against
each other by the preload of the elastic member 70 in the state, as
shown in FIG. 8, while the compressor 100 is in a stopped state.
Therefore, the abnormal noise is hardly generated during a start-up
of the compressor 100 because of the preload that acts to keep the
outer periphery of the rotary shaft 40 and the surface 68 of the
balancer-integrated bush 60 to be in contact with each other.
[0060] Furthermore, the preload of the elastic member 70 is also
effective during the operation of the compressor 100. When the
cooling load of the compressor 100 is small, the rotary shaft 40 is
rotated at a low speed. If it were not for the elastic member 70,
it becomes difficult for the fixed and movable scroll wraps 22B,
21B to be kept in contact with each other with an appropriate
contact pressure, as a result of which the compression performance
of the compressor 100 is decreased. Meanwhile, the preload of the
elastic member 70 enables the orbital radius of the movable scroll
member 21 (bush 62) to be increased during the rotation of the
rotary shaft 40 at a low speed and allows the scroll wraps 22B, 21B
to be kept in contact with each other with an appropriate contact
pressure, thus preventing a decrease in the compression performance
of the compressor 100.
[0061] Providing the elastic member 70 between the rotary shaft 40
and the balancer-integrated bush 60 only requires to form the
fitting hole 42B and the fitting hole 67A in the rotary shaft 40
and the balancer-integrated bush 60 respectively, and to press-fit
the elastic member 70 in these holes 42B, 67A. Thus, the
manufacturing and the assembly of the compressor may be
accomplished with ease.
[0062] A second embodiment will be described with reference to
FIGS. 12 to 14. The compressor of the second embodiment is
designated by reference numeral 102. In the above-described first
embodiment, the elastic member 70 is provided between the outer
periphery of the rotary shaft 40 and the surface 68 of the
balancer-integrated bush 60. The surface 68 corresponds to a second
surface of the present invention. In the second embodiment, a
fitting hole 40K is formed in the rotary shaft 40 from the outer
periphery of the rotary shaft 40, and the elastic member 70 is
provided between the fitting hole 40K and the surface 68 of the
balancer-integrated bush 60. The fitting hole 40K corresponds to a
second shaft recess of the present invention. When the rotary shaft
40 and the balancer-integrated bush 60 are assembled, the elastic
member 70 is positioned adjacent to the edge end 68B of the surface
68 of the balancer-integrated bush 60 that is on the leading side
of the surface 69 with respect to the moving direction DR1.
[0063] Also in the second embodiment, the movable scroll wrap 21B
of the movable scroll member 21 is always urged by the preload of
the elastic member 70 in the direction that increases the orbital
radius of the movable scroll member 21, so that the same effects as
those of the above-described first embodiment are accomplished.
Instead of the fitting hole 40K, a recess may be formed in the
surface of the balancer-integrated bush 60 to receive the elastic
member 70. This recess corresponds to the second bush recess of the
present invention. Alternatively, the second shaft recess (40K) and
the second bush recess may cooperate to receive the elastic member
70. Furthermore, the positions of the elastic member 70 may be
determined according to any combination of the first embodiment and
the second embodiment.
[0064] The above embodiments have been described as the compressor
that is provided with a swing link mechanism in which the bush and
the balancer are swingable relative to the eccentric pin. The
technical concept of increasing the orbital radius of a movable
scroll member of a scroll type compressor by using the preload of
an elastic member such as 70 is also applicable to a slide link
mechanism in which the bush and the balancer are slidable relative
to the eccentric pin.
[0065] The above embodiments and other configurations have been
described to show an example of the scroll type compressor of the
present invention and are not intended to limit the scope of the
invention. The scope of the present invention is defined in
appended claims and intended to include equivalents and all changes
and modification that fall within the scope of the present
invention.
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