U.S. patent application number 12/349618 was filed with the patent office on 2009-07-16 for rotary compressor.
This patent application is currently assigned to FUJITSU GENERAL LIMITED. Invention is credited to Naoya MOROZUMI, Kenshi Ueda.
Application Number | 20090180912 12/349618 |
Document ID | / |
Family ID | 40601219 |
Filed Date | 2009-07-16 |
United States Patent
Application |
20090180912 |
Kind Code |
A1 |
MOROZUMI; Naoya ; et
al. |
July 16, 2009 |
ROTARY COMPRESSOR
Abstract
A rotary compressor includes a compressing section including a
cylindrical cylinder, two end plates closing both ends of the
cylinder, respectively, and a piston held by an eccentric section
of a rotary shaft driven to rotate by a motor. A working chamber is
formed between the piston and the cylinder inner wall. The rotary
compressor also includes a vane protruding from within a vane
groove of the cylinder into the working chamber; an airtight
compressor housing accommodating therein the compressing section; a
suction hole provided in the cylinder and communicating the suction
chamber with a low-pressure side of a refrigerating cycle; and a
discharge hole provided in one of the end plates and communicating
the compression chamber with a high-pressure side of the
refrigerating cycle. An auxiliary discharge hole different from the
discharge hole is provided in the one end plate.
Inventors: |
MOROZUMI; Naoya; (Kanagawa,
JP) ; Ueda; Kenshi; (Kanagawa, JP) |
Correspondence
Address: |
MCDERMOTT WILL & EMERY LLP
600 13TH STREET, N.W.
WASHINGTON
DC
20005-3096
US
|
Assignee: |
FUJITSU GENERAL LIMITED
|
Family ID: |
40601219 |
Appl. No.: |
12/349618 |
Filed: |
January 7, 2009 |
Current U.S.
Class: |
418/229 ;
62/401 |
Current CPC
Class: |
F04C 29/12 20130101;
F04C 18/3564 20130101; F04C 23/008 20130101 |
Class at
Publication: |
418/229 ;
62/401 |
International
Class: |
F01C 1/00 20060101
F01C001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 11, 2008 |
JP |
2008-004337 |
Claims
1. A rotary compressor comprising: a compressing section including
a cylindrical cylinder, two end plates closing both ends of the
cylinder, respectively, a piston held by an eccentric section of a
rotary shaft driven to rotate by a motor, and revolving in the
cylinder along a cylinder inner wall of the cylinder, a working
chamber being formed between the piston and the cylinder inner
wall, and a vane protruding from within a vane groove of the
cylinder into the working chamber, abutting on the piston, and
dividing the working chamber into a suction chamber and a
compression chamber; an airtight compressor housing accommodating
therein the compressing section; a suction hole provided in the
cylinder and communicating the suction chamber with a low-pressure
side of a refrigerating cycle; and a discharge hole provided in one
of the end plates and communicating the compression chamber with a
high-pressure side of the refrigerating cycle, wherein an auxiliary
discharge hole different from the discharge hole is provided in the
one end plate.
2. The rotary compressor according to claim 1, wherein discharge
valves are provided in the discharge hole and the auxiliary
discharge hole, respectively, and concave portions accommodating
therein the discharge valves are separately provided in each of the
end plates, respectively.
3. The rotary compressor according to claim 1, wherein integrated
L-shaped discharge valves are provided in the discharge hole and
the auxiliary discharge hole, respectively, and a concave portion
accommodating therein the integrated L-shaped discharge valves and
having a fixed portion common to the L-shaped discharge valves is
provided in each of the end plates.
4. The rotary compressor according to claim 1, wherein a discharge
groove communicating with the discharge hole is provided in a
region of the cylinder inner wall corresponding to a position of
the discharge hole provided in the one end plate, and no discharge
groove is provided in a region of the cylinder inner wall
corresponding to a position of the auxiliary discharge hole
provided in the one end plate.
5. A rotary compressor comprising: a low-stage compressing section
including a cylindrical low-stage cylinder, a low-stage end plate
closing one end of the low-stage cylinder, a low-stage piston held
by a low-stage eccentric section of a rotary shaft driven to rotate
by a motor and revolving in the low-stage cylinder along a
low-stage cylinder inner wall of the low-stage cylinder, a
low-stage working chamber being formed between the low-stage piston
and the low-stage cylinder inner wall, and a low-stage vane
protruding from within a low-stage vane groove of the low-stage
cylinder into the low-stage working chamber, abutting on the
low-stage piston, and dividing the low-stage working chamber into a
low-stage suction chamber and a low-stage compression chamber; a
high-stage compressing section stacked on the low-stage compressing
section via an intermediate partition plate, the high-stage
compressing section including a cylindrical high-stage cylinder, a
high-stage end plate closing one end of the high-stage cylinder, a
high-stage piston held by a high-stage eccentric section of the
rotary shaft driven to rotate by the motor, and revolving in the
high-stage cylinder along a high-stage cylinder inner wall of the
high-stage, a high-stage working chamber being formed between the
high-stage piston and the high-stage cylinder inner wall, and a
high-stage vane protruding from within a high-stage vane groove of
the high-stage cylinder into the high-stage working chamber,
abutting on the high-stage piston, and dividing the high-stage
working chamber into a high-stage suction chamber and a high-stage
compression chamber; an airtight compressor housing accommodating
therein the low-stage compressing section and the high-stage
compressing section; a low-stage suction hole provided in the
low-stage cylinder and communicating the low-stage suction chamber
with a low-pressure side of a refrigerating cycle; a low-stage
discharge hole provided in the low-stage end plate and
communicating the low-stage compression chamber with a high-stage
suction hole provided in the high-stage cylinder; and a high-stage
discharge hole provided in the high-stage end plate and
communicating the high-stage compression chamber with a
high-pressure side of the refrigerating cycle, wherein a low-stage
auxiliary discharge hole different from the low-stage discharge
hole is provided in the low-stage end plate.
6. The rotary compressor according to claim 5, wherein discharge
valves are provided in the low-stage discharge hole and the
low-stage auxiliary discharge hole, respectively, and concave
portions accommodating therein the discharge valves are separately
provided in the low-stage end plate, respectively.
7. The rotary compressor according to claim 5, wherein integrated
L-shaped discharge valves are provided in the low-stage discharge
hole and the low-stage auxiliary discharge hole, respectively, and
a concave portion accommodating therein the integrated L-shaped
discharge valves and having a fixed portion common to the L-shaped
discharge valves is provided in the low-stage end plate.
8. The rotary compressor according to claim 5, wherein a discharge
groove communicating with the low-stage discharge hole is provided
in a region of the low-stage cylinder inner wall corresponding to a
position of the low-stage discharge hole provided in the one end
plate, and no discharge groove is provided in a region of the
low-stage cylinder inner wall corresponding to a position of the
low-stage auxiliary discharge hole provided in the low-stage end
plate.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a rotary compressor used in
a refrigerating cycle of an air-conditioner.
[0003] 2. Description of the Related Art
[0004] There is conventionally known a rotary compressor configured
so that a rotary compressor element and an electric element that
drives the compressor element are pressed into and held in a
cylindrical airtight container with an internal pressure of the
container kept high. Furthermore, the rotary compressor is
configured so that a discharge port (discharge hole) and a
discharge valve opened or closed according to a magnitude of a
discharge pressure are provided in each of an upper bearing (end
plate) closing an upper opening of a cylindrical compression
chamber of a cylinder and forming one bearing of a rotary shaft of
the electric element and a lower bearing (end plate) closing a
lower opening of the compression chamber and forming another
bearing of the rotary shaft. The rotary compressor of this type is
disclosed in, for example, Japanese Utility Model Application
Laid-Open No. S56-175594.
[0005] There is also known a two-stage rotary compressor configured
so that two stages of rotary compressing sections are stacked and
so that a compression target fluid is compressed by the low-stage
compressing section and the high-stage compressing section by two
stages. Furthermore, the two-stage rotary compressor is configured
so that an inside diameter of a compression chamber of the
low-stage compressing section is set larger than that of a
compression chamber of the high-stage compressing section.
Moreover, a second discharge valve chamber (discharge hole) of the
low-stage compressing section different from a first discharge
valve chamber provided in a main bearing (end plate) is arranged at
a position of a partition plate dividing a compressing section into
the low-stage compressing section and the high-stage compressing
section, which portion corresponds to an outer portion of the
compression chamber of the low-stage compressing section. The
compressor of this type is disclosed in, for example, Japanese
Patent Application Laid-Open No. S63-272988.
[0006] Furthermore, there is known a compressor configured to
include, in an airtight container, an electric element and a
compressor element driven by the electric element and including a
compression chamber that compresses a cooling medium containing
lubricating oil. The compression chamber includes an introduction
port for introducing the cooling medium containing the lubricating
oil into the compression chamber, a first discharge port from which
the compressed cooling medium is discharged, and a second discharge
port from which the lubricating oil is discharged. A first
discharge valve opened when a pressure of the compressed cooling
medium reaches a first pressure in the compression chamber is
provided in the first discharge port. A second discharge valve
opened at a second pressure higher than the first pressure is
provided in the second discharge port. The compressor of this type
is disclosed in, for example, Japanese Patent Application Laid-Open
No. 2006-275035.
[0007] An inverter-type rotary compressor has the following
problems. Particularly during high-speed rotation, over-compression
loss caused by a flow resistance of the cooling medium in the
discharge port increases and the loss causes deterioration in
efficiency of the rotary compressor. If a diameter of the discharge
hole is increased to reduce the flow resistance, it is necessary to
increase a thickness of the valve to ensure strength of the
discharge port. If the valve is thicker, opening of the valve
delays, resulting in the over-compression loss.
[0008] Moreover, according to the technique disclosed in Japanese
Utility Model Application Laid-Open No. S56-175594, the discharge
ports (discharge holes) are provided in both of the upper and lower
bearings, respectively. Due to this, the structure of the
compressing section is complicated, resulting in an increase in
manufacturing cost of the rotary compressor. According to the
technique disclosed in the Japanese Patent Application Laid-Open
No. S63-272988, the discharge valve chambers (discharge holes) are
provided in both the main baring and the partition plate,
respectively. Similarly to the technique disclosed in Japanese
Utility Model Application Laid-Open No. 56-175594, the structure of
each of the compressing sections is complicated, resulting in an
increase in manufacturing cost of the rotary compressor.
[0009] According to the conventional technique disclosed in
Japanese Patent Application Laid-Open No. 2006-275035, if the
compressor is actuated to perform only cooling operation in a
refrigerating and cooling cycle, a cooling medium gas inlet path on
a front-stage (low-stage) compressing section of the two-stage
compressor is completely cut off and the cooling medium gas is
sucked in only from a rear-stage (high-stage) compressing section.
At this time, a pressure of the front-stage (low-stage) compressing
section is close to vacuum, the lubricating oil is impregnated into
the front-stage compressing section from narrow gaps formed by
components constituting a compression chamber of the front-side
compressing section, and the compression chamber turns into a
liquid compression state, thereby disadvantageously and greatly
deteriorating efficiency of the compressor. The second discharge
port is intended to discharge the lubricating oil from the
compression chamber so as to prevent the deterioration in
efficiency. Accordingly, during high-speed rotation of the
compressor, the second discharge port is disadvantageously
incapable of reducing the over-compression loss caused by the flow
resistance of the cooling medium in the discharge port.
SUMMARY OF THE INVENTION
[0010] It is an object of the present invention to at least
partially solve the problems in the conventional technology.
[0011] According to an aspect of the present invention, a rotary
compressor includes a compressing section. The compressing section
includes a cylindrical cylinder; two end plates closing both ends
of the cylinder, respectively; a piston held by an eccentric
section of a rotary shaft driven to rotate by a motor, and
revolving in the cylinder along a cylinder inner wall of the
cylinder, a working chamber being formed between the piston and the
cylinder inner wall; and a vane protruding from within a vane
groove of the cylinder into the working chamber, abutting on the
piston, and dividing the working chamber into a suction chamber and
a compression chamber. The rotary compressor also includes an
airtight compressor housing accommodating therein the compressing
section; a suction hole provided in the cylinder and communicating
the suction chamber with a low-pressure side of a refrigerating
cycle; and a discharge hole provided in one of the end plates and
communicating the compression chamber with a high-pressure side of
the refrigerating cycle. In the one end plate, an auxiliary
discharge hole different from the discharge hole is provided.
[0012] According to another aspect of the present invention, a
rotary compressor includes a low-stage compressing section and a
high-stage compressing section stacked on the low-stage compressing
section via an intermediate partition plate. The low-stage
compressing section includes a cylindrical low-stage cylinder; a
low-stage end plate closing one end of the low-stage cylinder; a
low-stage piston held by a low-stage eccentric section of a rotary
shaft driven to rotate by a motor and revolving in the low-stage
cylinder along a low-stage cylinder inner wall of the low-stage
cylinder, a low-stage working chamber being formed between the
low-stage piston and the low-stage cylinder inner wall; and a
low-stage vane protruding from within a low-stage vane groove of
the low-stage cylinder into the low-stage working chamber, abutting
on the low-stage piston, and dividing the low-stage working chamber
into a low-stage suction chamber and a low-stage compression
chamber. The high-stage compressing section includes a cylindrical
high-stage cylinder; a high-stage end plate closing one end of the
high-stage cylinder; a high-stage piston held by a high-stage
eccentric section of the rotary shaft driven to rotate by the motor
and revolving in the high-stage cylinder along a high-stage
cylinder inner wall of the high-stage cylinder, a high-stage
working chamber being formed between the high-stage piston and the
high-stage cylinder inner wall; and a high-stage vane protruding
from within a high-stage vane groove of the high-stage cylinder
into the high-stage working chamber, abutting on the high-stage
piston, and dividing the high-stage working chamber into a
high-stage suction chamber and a high-stage compression chamber.
The rotary compressor also includes an airtight compressor housing
accommodating therein the low-stage compressing section and the
high-stage compressing section; a low-stage suction hole provided
in the low-stage cylinder and communicating the low-stage suction
chamber with a low-pressure side of a refrigerating cycle; a
low-stage discharge hole provided in the low-stage end plate and
communicating the low-stage compression chamber with a high-stage
suction hole provided in the high-stage cylinder; and a high-stage
discharge hole provided in the high-stage end plate and
communicating the high-stage compression chamber with a
high-pressure side of the refrigerating cycle. In the low-stage end
plate, a low-stage auxiliary discharge hole different from the
low-stage discharge hole is provided.
[0013] The above and other objects, features, advantages and
technical and industrial significance of this invention will be
better understood by reading the following detailed description of
presently preferred embodiments of the invention, when considered
in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a longitudinal sectional view of a rotary
compressor according to a first embodiment of the present
invention;
[0015] FIG. 2 is a top view of a compressing section of the rotary
compressor shown in FIG. 1;
[0016] FIG. 3 is a perspective view of an upper surface of the
compressing section closed by one of end plates;
[0017] FIG. 4 is a chart showing the relationship between a
revolution angle of a piston and a discharge pressure;
[0018] FIG. 5 is a chart showing the relationship between the
revolution angle of the piston and a change of a volume of a
compression chamber;
[0019] FIG. 6 is a chart showing the relationship between the
revolution angle of the piston and a change rate of the volume of
the compression chamber;
[0020] FIG. 7 is a longitudinal sectional view of a rotary
compressor according to a second embodiment of the present
invention;
[0021] FIG. 8 is a bottom view of a low-stage compressing section
of the rotary compressor shown in FIG. 7;
[0022] FIG. 9 is a cross-sectional view of a high-stage compressing
section of the rotary compressor shown in FIG. 7;
[0023] FIG. 10 is a perspective view of a lower surface of the
low-stage compressing section closed by a low-stage end plate;
[0024] FIG. 11 is a chart showing the relationship between a
revolution angle of a piston and a discharge pressure of the
low-stage compressing section;
[0025] FIG. 12 is a bottom view of a low-stage compressing section
of a rotary compressor according to a modification of the second
embodiment;
[0026] FIG. 13 is a perspective view of a lower surface of the
low-stage compressing section closed by a low-stage end plate
according to the modification of the second embodiment;
[0027] FIG. 14 is a longitudinal sectional view of a rotary
compressor according to a third embodiment of the present
invention;
[0028] FIG. 15 is a cross-sectional view of first and second
compressing sections of the rotary compressor shown in FIG. 14;
[0029] FIG. 16 is a top view of a compressing section of a rotary
compressor according to a fourth embodiment of the present
invention; and
[0030] FIG. 17 is a top view of the compressing section of the
rotary compressor according to the first embodiment for
reference.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMETNS
[0031] Exemplary embodiments of a rotary compressor according to
the present invention will be described below with reference to the
accompanying drawings. It is to be noted that the present invention
is not limited to the embodiments.
First Embodiment
[0032] FIG. 1 is a longitudinal sectional view of a rotary
compressor according to a first embodiment of the present
invention. FIG. 2 is a top view of a compressing section of the
rotary compressor shown in FIG. 1. FIG. 3 is a perspective view of
an upper surface of the compressing section closed by one of end
plates. FIG. 4 is a chart showing the relationship between a
revolution angle of a piston and a pressure of a compression
chamber. FIG. 5 is a chart showing the relationship between the
revolution angle of the piston and a volume of the compression
chamber. FIG. 6 is a chart showing the relationship between the
revolution angle of the piston and a change rate of the volume of
the compression chamber.
[0033] As shown in FIG. 1, a rotary compressor 1 according to the
first embodiment includes, in an airtight cylindrical compressor
housing 10, a compressing section 12, and a motor 11 driving the
compressing section 12.
[0034] A stator 111 of the motor 11 is fixedly shrunk to an inner
circumferential surface of the compressor housing 10. A rotor 112
of the motor 11 is arranged in a central portion of the stator 111
and fixedly shrunk to a rotary shaft 15 mechanically connecting the
motor 11 to the compressing section 12.
[0035] As shown in FIGS. 1 and 2, the compressing section 12
includes a short cylindrical cylinder 121. A cylindrical cylinder
inner wall 123 is formed on the cylinder 121 to be concentric with
the motor 11. A cylindrical piston 125 having an outside diameter
smaller than a diameter of the cylinder inner wall 123 is arranged
in the cylinder inner wall 123, and a working chamber 130
(compression space) sucking in, compressing, and discharging a
cooling medium is formed between the cylinder inner wall 123 and
the piston 125.
[0036] A vane groove 128 is formed in the cylinder 121 in a range
of an entire length of the cylinder 121 from the cylinder inner
wall 123 in a radial direction of the cylinder 121. A flat vane 127
is fitted into the vane groove 128. A spring, not shown, is
arranged in an inner part of the vane groove 128. In a normal
state, the vane 127 protrudes from within the vane groove 128 into
the working chamber 130 by a repulsive force of the spring, a tip
end of the vane 127 abuts on an outer circumferential surface of
the piston 125, and the vane 127 divides the working chamber 130
(compression space) into a suction chamber 131 and a compression
chamber 133.
[0037] A backpressure introduction path 129 communicating the inner
part of the vane groove 128 with an interior of the compressor
housing 10 and applying a backpressure to the vane 127 is formed on
the cylinder 121. A suction hole 135 communicating with the suction
chamber 131 is provided in the cylinder 121 to suck the cooling
medium into the suction chamber 131.
[0038] As shown in FIG. 1, one end plate 160A is disposed on an
upper end of the cylinder 121 and closes an upper portion of the
working chamber 130 of the cylinder 121. The other end plate 160B
is disposed on a lower end of the cylinder 121 and closes a lower
portion of the working chamber 130.
[0039] A sub bearing 161B is formed on the other end plate 160B and
a sub bearing support 151 of the rotary shaft 15 is rotatably
supported by the sub bearing 161B. A main bearing 161A is formed on
one end plate 160A and a main bearing support 153 of the rotary
shaft 15 is rotatably supported by the main bearing 161A.
[0040] The rotary shaft 15 includes an eccentric section 152 and
the eccentric section 152 rotatably holds the piston 125 of the
compressing section 12. When the rotary shaft 15 rotates, the
piston 125 revolves clockwise in the cylinder 121 along the
cylinder inner wall 123 in FIGS. 2 and 3 and the vane 127 follows
to reciprocate. Volumes of the suction chamber 131 and the
compression chamber 133 continuously change by movements of the
piston 125 and the vane 127, and the compressing section 121
continuously sucks in, compresses, and discharges the cooling
medium.
[0041] As shown in FIG. 1, a muffler cover 170 is disposed above
one end plate 160A and a muffler chamber 180 is formed between the
muffler cover 170 and the end plate 160A. A discharge portion of
the compressing section 12 communicates with the interior of the
compressor housing 10 via the muffler chamber 180. Accordingly, a
discharge hole 190 communicating the compression chamber 133 of the
cylinder 121 with the muffler chamber 180 is provided in one end
plate 160A near the vane 127 and a discharge valve 200 preventing
backflow of the compressed cooling medium is provided in the
discharge hole 190.
[0042] Furthermore, a discharge valve holding member 201 as well as
the discharge valve 200 is fixed to the end plate 160A by a rivet
so as to restrict a deflection opening amount of the discharge
valve 200. The muffler chamber 180 reduces pressure pulsation of
the discharged cooling medium.
[0043] The other end plate 160B, the cylinder 121, one end plate
160A, and the muffler cover 170 are integrally fastened by a bolt
that is not shown. Among the integrally fastened constituent
elements of the compressing section 12, an outer peripheral portion
of one end plate 160A is fixedly bonded to the compressor housing
10 by spot welding to thereby fix the compressing section 12 to the
compressor housing 10.
[0044] As shown in FIG. 1, a through hole 101 is provided in an
outer circumferential wall of the cylindrical compressor housing
10. An accumulator 25 formed of an independent and cylindrical
airtight container is arranged outside of the compressor housing 10
and held by an accumulator holder 251 and an accumulator band
253.
[0045] A system connecting pipe 255 connecting the accumulator 25
to a low-pressure side of a refrigerating cycle is provided in a
central portion of a top surface of the accumulator 25. A
low-pressure connecting pipe 31 having one end extending toward an
upper portion of an interior of the accumulator 25 and the other
end connected to the other end of a suction pipe 104 is connected
to a bottom through hole 257 provided at a bottom of the
accumulator 25.
[0046] The low-pressure connecting pipe 31 introducing a
low-pressure cooling medium of the refrigerating cycle to the
compressing section 12 via the accumulator 25 is connected to the
suction hole 135 (see FIG. 2) via the through hole 101 and the
suction pipe 104. Accordingly, the suction hole 135 communicates
with the low-pressure side of the refrigerating cycle.
[0047] A discharge pipe 107 connected to a high-pressure side of
the refrigerating cycle and discharging a high pressure cooling
medium toward the high-pressure side of the refrigerating cycle is
connected to a top of the compressor housing 10. Accordingly, the
discharge hole 190 communicates with the high-pressure side of the
refrigerating cycle.
[0048] The compressor housing 10 is filled with lubricating oil
almost up to a height of the cylinder 121. The lubricating oil
circulates in the compressing section 12 by a vane pump, not shown,
attached to a lower portion of the rotary shaft 15 and seals a
portion defining the working chamber 130 (compression space) for
the compressed cooling medium by lubrication of sliding components
and narrow gaps.
[0049] As shown in FIG. 3, the rotary compressor 1 according to the
first embodiment is characteristically configured so that an
auxiliary discharge hole 190A communicating the compression chamber
133 with the high-pressure side of the refrigerating cycle is
provided in one end plate 160A in which the discharge hole 190 is
provided. The discharge valve 200 and the discharge valve holding
member 201 are disposed in the auxiliary discharge hole 190A
similarly to the discharge hole 190.
[0050] As shown in FIGS. 2 and 3, a discharge groove 124
communicating with the discharge hole 190 is provided in a region
of the cylinder inner wall 123 corresponding to a position of the
discharge hole 190 provided in one end plate 160A. A discharge
groove 124A communicating with the auxiliary discharge hole 190A is
provided in a region of the cylinder inner wall 123 corresponding
to a position of the auxiliary discharge hole 190A. The discharge
grooves 124 and 124A reduce the flow resistance of the cooling
medium discharged from the compression chamber 133 into the
discharge hole 190 and the auxiliary discharge hole 190A.
[0051] The auxiliary discharge hole 190A is provided at a position
away from the vane groove 128 by 230.degree. to 300.degree. in a
direction of revolution of the piston 125 along the cylinder inner
wall 123. The reason is as follows. As shown in FIG. 3, concave
portions 190K and 190AK are provided in the end plate 160A
separately to accommodate the discharge valves 200 and the
discharge valve holding members 201 (see FIG. 1) preventing
backflow of the cooling medium in the discharge hole 190 and the
auxiliary discharge hole 190A, respectively. If the concave
portions 190K and 190AK interfere with each other, a rib 190R wears
away and strength of the end plate 160A weakens. To prevent this,
the auxiliary discharge hole 190A is provided at the position
within 300.degree. from the vane groove 128 in the direction of
revolution of the piston 125 along the cylinder inner wall 123.
[0052] On the other hand, as shown in FIG. 4, when the piston 125
revolves clockwise by about 210.degree. from the position of the
vane groove 128, a pressure of the compression chamber 133 reaches
a discharge pressure according to rated cooling conditions and the
discharge valves 200 that have closed the discharge hole 190 and
the auxiliary discharge hole 190A, respectively are opened.
Furthermore, as shown in FIG. 6, the rotary compressor 1 has a high
change rate of a volume of the compression chamber 133, that is, a
high discharge flow speed when the piston 125 revolves by
135.degree. to 225.degree. from the position of the vane groove
128.
[0053] Accordingly, right after the discharge valve 200 opens by
210.degree., a flow speed of the discharged cooling medium is the
highest and pressure loss is the greatest. If the auxiliary
discharge hole 190A is communicable without being cut off by end
surfaces of the compression chamber 133 and the piston 125 right
after the discharge valve 200 opens by 210.degree., the auxiliary
discharge hole 190A operates effectively. Due to this, the
auxiliary discharge hole 190A is provided at the position away from
the vane groove 128 at least by 230.degree. in the direction of the
revolution of the piston 125 along the cylinder inner wall 123.
However, in the present invention, the position of the auxiliary
discharge hole 190A is not limited to the above-stated position. As
long as the auxiliary discharge hole 190A is used under conditions
that the strength of the end plate 160A is sufficiently high, the
rib 190R may not be provided and the auxiliary discharge hole 190A
may be provided at a position away from the vane groove 128 by
300.degree. or more.
[0054] Operation of the rotary compressor 1 described so far will
next be described. If the rotary compressor 1 is actuated, the
cooling medium flowing from the low-pressure side of the
refrigerating cycle into the accumulator 25 through the system
connecting pipe 255 is separated into a liquid cooling medium and a
gas cooling medium. Specifically, the liquid cooling medium is
accumulated in a lower portion of the accumulator 25 and the gas
cooling medium is accumulated in an upper portion thereof.
[0055] When the piston 125 revolves in the cylinder 121 and a
volume of the suction chamber 131 increases, the gas cooling medium
in the accumulator 25 is sucked into the suction chamber 131 of the
compressing section 12 through the low-pressure connecting pipe 31,
the suction pipe 104, and the suction hole 135. When the piston 125
revolves once, the suction chamber 131 is cut off from the suction
hole 135 and changed over to the compression chamber 133, and the
cooling medium is compressed in the compression chamber 133.
[0056] If the pressure of the compressed cooling medium in the
compression chamber 133 becomes equal to a pressure of the muffler
chamber 180 located downstream of the discharge valves 200 provided
in the discharge hole 190 and the auxiliary discharge hole 190A,
respectively, that is, discharge pressure, then the discharge
valves 200 open, and the cooling medium is discharged into the
muffler chamber 180 through the discharge hole 190 and the
auxiliary discharge hole 190A at low flow resistance and the
pressure pulsation causing noise is reduced in the muffler chamber
180. The cooling medium is discharged, as a high-pressure cooling
medium, into the compressor housing 10. Thereafter, the
high-pressure cooling medium is fed to an upper portion of the
motor 11 through a core notch, not shown, of the stator 111 of the
motor 11 and a gap between a core and a coil, and discharged toward
the high-pressure side of the refrigerating cycle through the
discharge pipe 107.
[0057] In the rotary compressor 1 according to the first
embodiment, the cooling medium is discharged into the muffler
chamber 180 through the discharge hole 190 and the auxiliary
discharge hole 190A at the low flow resistance. Therefore, the
over-compression loss can be reduced. Further, there is no need to
work the concave portion 190K accommodating therein the discharge
hole 190, the valve seat around the discharge hole 190, and the
discharge valve 200 to be provided on each of the end plates 160A
and 160B. Therefore, working cost can be reduced.
Second Embodiment
[0058] FIG. 7 is a longitudinal sectional view of a rotary
compressor according to a second embodiment of the present
invention. FIG. 8 is a bottom view of a low-stage compressing
section of the rotary compressor shown in FIG. 7. FIG. 9 is a
cross-sectional view of a high-stage compressing section of the
rotary compressor shown in FIG. 7. FIG. 10 is a perspective view of
a lower surface of the low-stage compressing section closed by a
low-stage end plate. FIG. 11 is a chart showing the relationship
between a revolution angle of a piston and a discharge pressure of
the low-stage compressing section. FIG. 12 is a bottom view of a
low-stage compressing section of a rotary compressor according to a
modification of the second embodiment. FIG. 13 is a perspective
view of a lower surface of the low-stage compressing section closed
by a low-stage end plate according to the modification of the
second embodiment.
[0059] As shown in FIG. 7, a rotary compressor 2 according to the
second embodiment includes, in an airtight cylindrical compressor
housing 10, a compressing section 12 and a motor 11 driving the
compressing section 12.
[0060] A stator 111 of the motor 11 is fixedly shrunk to an inner
circumferential surface of the compressor housing 10. A rotor 112
of the motor 11 is arranged in a central portion of the stator 111
and fixedly shrunk to a rotary shaft 15 mechanically connecting the
motor 11 to the compressing section 12.
[0061] The compressing section 12 includes a low-stage compressing
section 12L and a high-stage compressing section 12H connected in
series to the low-stage compressing section 12L and disposed to be
stacked on an upper side of the low-stage compressing section 12L.
As shown in FIGS. 7 and 8, the low-stage compressing section 12L
includes a short cylindrical cylinder 121L. As shown in FIGS. 7 and
9, the high-stage compressing section 12H includes a short
cylindrical cylinder 121H.
[0062] Cylindrical low-stage and high-stage cylinder inner walls
123L and 123H are formed on the low-stage cylinder 121L and the
high-stage cylinder 121H to be concentric with the motor 11,
respectively. Cylindrical low-stage and high-stage pistons 125L and
125H having outside diameters smaller than diameters of the
low-stage and high-stage cylinder inner walls 123L and 123H are
arranged in the low-stage and high-stage cylinder inner walls 123L
and 123H, respectively. Further, low-stage and high-stage working
chambers 130L and 130H (compression spaces) absorbing, compressing,
and discharging a cooling medium are formed between the low-stage
and high-stage cylinder inner walls 123L and 123H and the low-stage
and high-stage pistons 125L and 124H, respectively.
[0063] Low-stage and high-stage vane grooves 128L and 128H are
formed in the low-stage and high-stage cylinders 121L and 121H in a
range of entire lengths of the low-stage and high-stage cylinders
121L and 121H from the low-stage and high-stage cylinder inner
walls 123L and 123H in a radial direction of the low-stage and
high-stage cylinders 121L and 121H, respectively. Low-stage and
high-stage flat vanes 127L and 127H are fitted into the low-stage
and high-stage vane grooves 128L and 128H, respectively.
[0064] To make a volume of the high-stage working chamber 130H of
the high-stage compressing section 12H smaller than that of the
low-stage working chamber 130L of the low-stage compressing section
12L, the high-stage cylinder 121H, the high-stage piston 125H, and
the high-stage vane 127H are set lower in axial height than the
low-stage cylinder 121L, the low-stage piston 125L, and the
low-stage vane 127L, respectively.
[0065] Low-stage and high-stage springs, not shown, are arranged in
inner parts of the low-stage and high-stage vane grooves 128L and
128H, respectively. In a normal state, the low-stage and high-stage
vanes 127L and 127H protrude from within the low-stage and
high-stage vane grooves 128L and 128H into the low-stage and
high-stage working chambers 130L and 130H by repulsive forces of
the low-stage and high-stage springs, respectively. Tip end of the
low-stage and high-stage vanes 127L and 127H abut on outer
circumferential surfaces of the low-stage and high-stage pistons
125L and 125H, and the low-stage and high-stage vanes 127L and 127H
divide the low-stage and high-stage working chambers 130L and 130H
(compression spaces) into low-stage and high-stage suction chambers
131L and 131H and low-stage and high-stage compression chambers
133L and 133H, respectively.
[0066] Low-stage and high-stage backpressure introduction paths
129L and 129H communicating the inner parts of the low-stage and
high-stage vane grooves 128L and 128H with an interior of the
compressor housing 10 and applying a backpressure to the low-stage
and high-stage vanes 127L and 127H are formed on the low-stage and
high-stage cylinders 121L and 121H, respectively.
[0067] Low-stage and high-stage suction holes 135L and 135H
communicating with the low-stage and high-stage suction chambers
131L and 131H are provided in the low-stage and high-stage
cylinders 121L and 121H to absorb the cooling medium into the
low-stage and high-stage suction chambers 131L and 131H,
respectively.
[0068] As shown in FIG. 7, an intermediate partition plate 140 is
provided between the low-stage cylinder 121L and the high-stage
cylinder 121H to divide a working chamber into the low-stage
working chamber 130L of the low-stage cylinder 121L and the
high-stage working chamber 130H of the high-stage cylinder 121H. A
low-stage end plate 160L is disposed on a lower end of the
low-stage cylinder 121L and closes the low-stage working chamber
130L of the low-stage cylinder 121L. A high-stage end plate 160H is
disposed on an upper end of the high-stage cylinder 121H and closes
the high-stage working chamber 130H of the high-stage cylinder
121H.
[0069] A sub bearing 161L is formed on the low-stage end plate 160L
and a sub bearing support 151 of the rotary shaft 15 is rotatably
supported by the sub bearing 161L. A main bearing 161H is formed on
the high-stage end plate 160H and a main bearing support 153 of the
rotary shaft 15 is rotatably supported by the main bearing
161H.
[0070] The rotary shaft 15 includes low-stage and high-stage
eccentric sections 152L and 152H eccentric to be shifted in phase
by 180.degree. from each other. The low-stage eccentric section
152L rotatably holds the low-stage piston 125L of the low-stage
compressing section 12L. The high-stage eccentric section 152H
rotatably holds the high-stage piston 125H of the high-stage
compressing section 12H.
[0071] When the rotary shaft 15 rotates, the low-stage and
high-stage pistons 125L and 125H revolve clockwise in the low-stage
and high-stage cylinders 121L and 121H along the low-stage and
high-stage cylinder inner walls 123L and 123H in FIG. 8 (revolve
counterclockwise in FIG. 9), and the low-stage and high-stage vanes
127L and 127H follow to reciprocate. Volumes of the low-stage and
high-stage suction chambers 131L and 131H and the low-stage and
high-stage compression chambers 133L and 133H continuously change
by movements of the low-stage and high-stage pistons 125L and 125H
and the low-stage and high-stage vanes 127L and 127H, respectively,
and the compressing section 12 continuously absorbs, compresses,
and discharges the cooling medium.
[0072] As shown in FIG. 7, a low-stage muffler cover 170L is
disposed below the low-stage end plate 160L and a low-stage muffler
chamber 180L is formed between the low-stage muffler cover 170L and
the low-stage end plate 160L. A discharge portion of the low-stage
compressing section 12L opens to the low-stage muffler chamber
180L. Accordingly, a low-stage discharge hole 190L communicating
the low-stage compression chamber 133L of the low-stage cylinder
121L with the low-stage muffler chamber 180L is provided in the
low-stage end plate 160L near the low-stage vane 127L and a
low-stage discharge valve 200L preventing backflow of the
compressed cooling medium is provided in the low-stage discharge
hole 190L.
[0073] As shown in FIG. 10, the low-stage muffler chamber 180L is
one annularly communicable chamber and a part of an intermediate
communicating path communicating a discharge side of the low-stage
compressing section 12L with a suction side of the high-stage
compressing section 12H. The low-stage muffler chamber 180L reduces
pressure pulsation of the discharged cooling medium.
[0074] Furthermore, a low-stage discharge valve holding member 201L
as well as the low-stage discharge valve 200L is fixed to the
low-stage end plate 160L by a rivet so as to restrict a deflection
opening amount of the low-stage discharge valve 200L. A low-stage
muffler discharge hole 210L discharging the cooling medium in the
low-stage muffler chamber 180L to outside is provided in an outer
peripheral wall of the low-stage end plate 160L. The low-stage
muffler discharge hole 210L is provided radially at a position in a
circumferential direction of the compressor housing 10 and
different in phase from the low-stage and high-stage suction holes
135L and 135H of the compressing section 12.
[0075] As shown in FIG. 7, a high-stage muffler cover 170H is
disposed above the high-stage end plate 160H and a high-stage
muffler chamber 180H is formed between the high-stage muffler cover
170H and the high-stage end plate 160H. A high-stage discharge hole
190H communicating the high-stage compression chamber 133H of the
high-stage cylinder 121H with the high-stage muffler chamber 180H
is provided in the high-stage end plate 160H near the high-stage
vane 127H and a high-stage discharge valve 200H preventing backflow
of the compressed cooling medium is provided in the high-stage
discharge hole 190H. Furthermore, a high-stage discharge valve
holding member 201H as well as the high-stage discharge valve 200H
is fixed to the high-stage end plate 160H by a rivet so as to
restrict a deflection opening amount of the high-stage discharge
valve 200H. The high-stage muffler chamber 180H reduces pressure
pulsation of the discharged cooling medium.
[0076] The low-stage cylinder 121L, the low-stage end plate 160L,
the low-stage muffler cover 170L, the high-stage cylinder 121H, the
high-stage end plate 160H, the high-stage muffler cover 170H, and
the intermediate partition plate 140 are integrally fastened by a
bolt that is not shown. Among the integrally fastened constituent
elements of the compressing section 12, an outer peripheral portion
of the high-stage end plate 160H is fixedly bonded to the
compressor housing 10 by spot welding to thereby fix the
compressing section 12 to the compressor housing 10.
[0077] As shown in FIG. 7, first, second, and third through holes
101, 102, and 103 are provided in an outer circumferential wall of
the cylindrical compressor housing 10 to be axially away from one
another in ascending order from a lower portion. An accumulator 25
formed of an independent and cylindrical airtight container is
arranged outside of the compressor housing 10 and held by an
accumulator holder 251 and an accumulator band 253.
[0078] A system connecting pipe 255 connecting the accumulator 25
to a low-pressure side of a refrigerating cycle is provided in a
central portion of a top surface of the accumulator 25. A
low-pressure connecting pipe 31 having one end extending toward an
upper portion of an interior of the accumulator 25 and the other
end connected to the other end of a suction pipe 104 is connected
to a bottom through hole 257 provided at a bottom of the
accumulator 25.
[0079] The low-pressure connecting pipe 31 introducing a
low-pressure cooling medium of the refrigerating cycle to the
compressing section 12 via the accumulator 25 is connected to the
low-stage suction hole 135L of the low-stage cylinder 121L via the
second through hole 102 and the low-stage suction pipe 104.
Accordingly, the low-stage suction hole 135L communicates with the
low-pressure side of the refrigerating cycle.
[0080] One end of the low-stage discharge pipe 105 is connected to
the low-stage muffler discharge hole 210L of the low-stage muffler
chamber 180L through the first through hole 101. One end of the
high-stage discharge suction pipe 106 is connected to the
high-stage suction hole 135H of the high-stage cylinder 121H
through the third through hole 103. Further, the other end of the
low-stage discharge pipe 105 is connected to the other end of the
high-stage suction pipe 106 by an intermediate connecting pipe 23.
A low-pressure connecting pipe 31 and the intermediate connecting
pipe 23 are formed so as not to interfere with each other.
[0081] A discharge portion of the high-stage compressing section
12H communicates with the interior of the compressor housing 10 via
the high-stage muffler chamber 180H. Namely, the high-stage
discharge hole 190H communicating the high-stage compression
chamber 133H of the high-stage cylinder 121H with the high-stage
muffler chamber 180H is provided in the high-stage end plate 160H,
and the high-stage discharge valve 200H preventing backflow of the
compressed cooling medium is disposed in the high-stage discharge
hole 190H.
[0082] A discharge pipe 107 connected to a high-pressure side of
the refrigerating cycle and discharging the high-pressure cooling
medium toward the high-pressure side of the refrigerating cycle is
connected to a top of the compressor housing 10. Accordingly, the
high-stage discharge hole 190H communicates with the high-pressure
side of the refrigerating cycle.
[0083] The compressor housing 10 is filled with lubricating oil
almost up to a height of the high-stage cylinder 121H. The
lubricating oil circulates in the compressing section 12 by a vane
pump, not shown, attached to a lower portion of the rotary shaft 15
and seals a portion defining the low-stage and high-stage working
chambers 130L and 130H (compression spaces) for the compressed
cooling medium by lubrication of sliding components and narrow
gaps.
[0084] As shown in FIG. 10, the rotary compressor 2 according to
the second embodiment is characteristically configured so that a
low-stage auxiliary discharge hole 190LL communicating the
low-stage compression chamber 133L with the high-stage compressing
section 12H is provided in the low-stage end plate 160L in which
the low-stage discharge hole 190L is provided. A low-stage
discharge valve 200L is disposed in the low-stage auxiliary
discharge hole 190LL similarly to the low-stage discharge hole
190L.
[0085] As shown in FIGS. 8 and 10, a discharge groove 124L
communicating with the low-stage discharge hole 190L is provided in
a region of the low-stage cylinder inner wall 123L corresponding to
a position of the low-stage discharge hole 190L provided in the
low-stage end plate 160L. A discharge groove 124LA communicating
with the low-stage auxiliary discharge hole 190LL is provided in a
region of the low-stage cylinder inner wall 123L corresponding to a
position of the low-stage auxiliary discharge hole 190LL. The
discharge grooves 124L and 124LA reduce the flow resistance of the
cooling medium discharged from the low-stage compression chamber
133L into the low-stage discharge hole 190L and the low-stage
auxiliary discharge hole 190LL.
[0086] The low-stage auxiliary discharge hole 190LL is provided at
a position away from the low-stage vane groove 128L by 190.degree.
to 300.degree. in a direction of revolution of the low-stage piston
125L along the low-stage cylinder inner wall 123L. The reason for
providing the low-stage auxiliary discharge hole 190LL at the
position within 300.degree. is the same as that described in the
first embodiment.
[0087] On the other hand, as shown in FIG. 11, when the low-stage
piston 125L revolves clockwise by about 170.degree. from the
position of the low-stage vane groove 128L, a pressure of the
low-stage compression chamber 133L reaches a low-stage discharge
pressure (an intermediate pressure) and the low-stage discharge
valves 200L that have closed the low-stage discharge hole 190L and
the low-stage auxiliary discharge hole 190LL, respectively are
opened. In other words, since a pressure ratio is lower than that
according to the first embodiment, the low-stage piston 125L opens
quickly by about 40.degree. as compared with the first
embodiment.
[0088] Furthermore, similarly to the first embodiment, as shown in
FIG. 11, the rotary compressor 2 has a high change rate of a volume
of the low-stage compression chamber 133L, that is, a high
discharge flow speed when the low-stage piston 125L revolves by
135.degree. to 225.degree. from the position of the low-stage vane
groove 128L. Accordingly, right after the low-stage discharge valve
200L opens by 170.degree., a flow speed of the discharged cooling
medium is the highest and pressure loss is the greatest. If the
low-stage auxiliary discharge hole 190LL is communicable without
being cut off by end surfaces of the low-stage compression chamber
133L and the low-stage piston 125L right after the low-stage
discharge valve 200 opens by 170.degree., the low-stage auxiliary
discharge hole 190LL operates effectively. Due to this, the
low-stage auxiliary discharge hole 190LL is provided at the
position away from the low-stage vane groove 128L at least by
190.degree. in the direction of the revolution of the low-stage
piston 125L along the low-stage cylinder inner wall 123L.
[0089] Operation of the rotary compressor 2 described so far will
next be described. If the rotary compressor 2 is actuated, the
cooling medium flowing from the low-pressure side of the
refrigerating cycle into the accumulator 25 through the system
connecting pipe 255 is separated into a liquid cooling medium and a
gas cooling medium. Specifically, the liquid cooling medium is
accumulated in a lower portion of the accumulator 25 and the gas
cooling medium is accumulated in an upper portion thereof.
[0090] When the low-stage piston 125L revolves in the low-stage
cylinder 121L and a volume of the low-stage suction chamber 131L
increases, the gas cooling medium in the accumulator 25 is absorbed
into the low-stage suction chamber 131L of the low-stage
compressing section 12L through the low-pressure connecting pipe
31, the low-stage suction pipe 104L, and the low-stage suction hole
135. When the low-stage piston 125L revolves once, the low-stage
suction chamber 131L is cut off from the low-stage suction hole
135L and changed over to the low-stage compression chamber 133L,
and the cooling medium is compressed in the low-stage compression
chamber 133L.
[0091] If the pressure of the compressed cooling medium in the
low-stage compression chamber 133L becomes equal to the pressure of
the low-stage muffler chamber 180L located downstream of the
low-stage discharge valves 200L provided in the low-stage discharge
hole 190L and the low-stage auxiliary discharge hole 190LL,
respectively, that is, the intermediate pressure (low-stage
discharge pressure), then the low-stage discharge valves 200L open,
and the cooling medium is discharged into the low-stage muffler
chamber 180L through the low-stage discharge hole 190L and the
low-stage auxiliary discharge hole 190LL at low flow resistance and
the pressure pulsation causing noise is reduced in the low-stage
muffler chamber 180L. Thereafter, the cooling medium is fed to the
high-stage suction chamber 131H of the high-stage compressing
section 12H through the low-stage discharge pipe 105, the
intermediate connecting pipe 23, and the high-stage suction hole
135H.
[0092] The cooling medium fed to the high-stage suction chamber
131H of the high-stage compressing section 12H is compressed and
discharged by similar operation to that of the low-stage
compressing section 12L and the pressure pulsation is reduced in
the high-stage muffler chamber 180H. Thereafter, the cooling medium
is discharged, as a high-pressure cooling medium, into the
compressor housing 10. Thereafter, the high-pressure cooling medium
is fed to an upper portion of the motor 11 through a core notch,
not shown, of the stator 111 of the motor 11 and a gap between a
core and a coil, and discharged toward the high-pressure side of
the refrigerating cycle through the discharge pipe 107.
[0093] In the rotary compressor 2 according to the second
embodiment, the cooling medium is discharged into the low-stage
muffler chamber 180L through the low-stage discharge hole 190L and
the low-stage auxiliary discharge hole 190LL at the low flow
resistance. Therefore, the over-compression loss can be reduced.
Further, manufacturing cost can be reduced as compared with of the
case in which the low-stage auxiliary discharge hole is provided in
the intermediate partition plate 140.
[0094] Moreover, in the two-stage rotary compressor 2, the pressure
ratio is shared between the two compression chambers and the
low-stage pressure ratio is generally, therefore, as low as 1.5 to
2.0. Accordingly, since the cooling medium is discharged from the
compression chambers in a state in which a volume of the cooling
medium is large, it is effective to provide the auxiliary discharge
hole particularly for reduction of the over-compression loss (flow
resistance).
[0095] FIG. 12 is a bottom view of a low-stage compressing section
according to a modification of the second embodiment. FIG. 13 is a
perspective view of a lower surface of the low-stage compressing
section closed by a low-stage end plate according to the
modification of the second embodiment. In the modification of the
second embodiment shown in FIGS. 12 and 13, concave portions 190K
and 190AK provided in the low-stage end plate 160L are caused to
interfere with each other, a rib 190R is removed, a fixed portion
190S common to integrated L-shaped lower-stage discharge valve and
lower-stage discharge valve holding member is provided, thereby
providing an L-shaped concave portion. The L-shaped concave portion
accommodates therein the integrated L-shaped lower-stage discharge
valve and lower-stage discharge valve holding member for preventing
backflow in the low-stage discharge hole 190L and the low-stage
auxiliary discharge hole 190LL.
[0096] According to the modification of the second embodiment, it
is possible to ensure that the low-stage end plate 160L has
sufficient strength by providing different concave portions near
the low-stage discharge hole 190L and the low-stage auxiliary
discharge hole 190LL, respectively. It is also possible to
integrate the low-stage discharge valve with the low-stage
discharge valve holding member by making only the fixed portion
190S common to the low-stage discharge valve and the low-stage
discharge valve holding member. Cost can be thereby reduced.
Third Embodiment
[0097] FIG. 14 is a longitudinal sectional view of a rotary
compressor according to a third embodiment of the present
invention. FIG. 15 is a cross-sectional view of a second
compressing section of the rotary compressor shown in FIG. 14.
[0098] As shown in FIG. 14, a rotary compressor 3 according to the
third embodiment includes, in an airtight cylindrical compressor
housing 10, a compressing section 12 and a motor 11 driving the
compressing section 12.
[0099] A stator 111 of the motor 11 is fixedly shrunk to an inner
circumferential surface of the compressor housing 10. A rotor 112
of the motor 11 is arranged in a central portion of the stator 111
and fixedly shrunk to a rotary shaft 15 mechanically connecting the
motor 11 to the compressing section 12.
[0100] The compressing section 12 includes a first compressing
section 12S and a second compressing section 12T connected in
parallel to the first compressing section 12S and disposed to be
stacked on an upper side of the first compressing section 12S. The
first and second compressing sections 12S and 12T include short
cylindrical cylinders 121S and 121T, respectively.
[0101] As shown in FIG. 15, circular first and second cylinder
inner walls 123S and 123T are formed on the first cylinder 121S and
the second cylinder 121T to be concentric with the motor 11,
respectively. Cylindrical first and second pistons 125S and 125T
having outside diameters smaller than diameters of the first and
second cylinder inner walls 123S and 123T are arranged in the first
and second cylinder inner walls 123S and 123T, respectively.
Further, first and second working chambers 130S and 130T
(compression spaces) absorbing, compressing, and discharging a
cooling medium are formed between the first and second cylinder
inner walls 123S and 123T and the first and second pistons 125S and
124T, respectively.
[0102] First and second vane grooves 128S and 128T are formed in
the first and second cylinders 121S and 121T in a range of entire
lengths of the first and second cylinders 121S and 121T from the
first and second cylinder inner walls 123S and 123T in a radial
direction of the first and second cylinders 121S and 121T,
respectively. First and second flat vanes 127S and 127T are fitted
into the first and second vane grooves 128S and 128T,
respectively.
[0103] To make a volume of the second working chamber 130T of the
second compressing section 12T smaller than that of the first
working chamber 130S of the first compressing section 12S, the
second cylinder 121T, the second piston 125T, and the second vane
127T are set lower in axial height than the first cylinder 121S,
the first piston 125S, and the first vane 127S, respectively.
[0104] First and second springs, not shown, are arranged in inner
parts of the first and second vane grooves 128S and 128T,
respectively. In a normal state, the first and second vanes 127S
and 127T protrude from within the first and second vane grooves
128S and 128T into the first and second working chambers 130S and
130T by repulsive forces of the first and second springs,
respectively. Tip end of the first and second vanes 127S and 127T
abut on outer circumferential surfaces of the first and second
pistons 125S and 125T, and the first and second vanes 127S and 127T
divide the first and second working chambers 130S and 130T
(compression spaces) into first and second suction chambers 131S
and 131T and first and second compression chambers 133S and 133T,
respectively.
[0105] First and second backpressure introduction paths 129S and
129T communicating the inner parts of the first and second vane
grooves 128S and 128T with an interior of the compressor housing 10
and applying a backpressure to the first and second vanes 127S and
127T are formed on the first and second cylinders 121S and 121T,
respectively.
[0106] First and second suction holes 135S and 135T communicating
with the first and second suction chambers 131S and 131T are
provided in the first and second cylinders 121S and 121T to absorb
the cooling medium into the first and second suction chambers 131S
and 131T, respectively.
[0107] As shown in FIG. 14, an intermediate partition plate 140 is
provided between the first cylinder 121S and the second cylinder
121T to divide a working chamber into the first working chamber
130S of the first cylinder 121S and the second working chamber 130T
of the second cylinder 121T. A first end plate 160S is disposed on
a lower end of the first cylinder 121S and closes the first working
chamber 130S of the first cylinder 121S. A second end plate 160T is
disposed on an upper end of the second cylinder 121T and closes the
second working chamber 130T of the second cylinder 121T.
[0108] A sub bearing 161S is formed on the first end plate 160S and
a sub bearing support 151 of the rotary shaft 15 is rotatably
supported by the sub bearing 161S. A main bearing 161T is formed on
the second end plate 160T and a main bearing support 153 of the
rotary shaft 15 is rotatably supported by the main bearing
161T.
[0109] The rotary shaft 15 includes first and second eccentric
sections 152S and 152T eccentric to be shifted in phase by
180.degree. from each other. The first eccentric section 152S
rotatably holds the first piston 125S of the first compressing
section 12S. The second eccentric section 152T rotatably holds the
second piston 125T of the second compressing section 12T.
[0110] When the rotary shaft 15 rotates, the first and second
pistons 125S and 125T revolve clockwise in the first and second
cylinders 121S and 121T along the first and second cylinder inner
walls 123S and 123T, and the first and second vanes 127S and 127T
follow to reciprocate. Volumes of the first and second suction
chambers 131S and 131T and the first and second compression
chambers 133S and 133T continuously change by movements of the
first and second pistons 125S and 125T and the first and second
vanes 127S and 127T, respectively, and the compressing section 12
continuously absorbs, compresses, and discharges the cooling
medium.
[0111] As shown in FIG. 14, a first muffler cover 170S is disposed
below the first end plate 160S and a first muffler chamber 180S is
formed between the first muffler cover 170S and the first end plate
160S. A discharge portion of the first compressing section 12S
opens to the first muffler chamber 180S. Namely, a first discharge
hole 190S communicating the first compression chamber 133S of the
first cylinder 121S with the first muffler chamber 180S is provided
in the first end plate 160S near the first vane 127S and a first
discharge valve 200S preventing backflow of the compressed cooling
medium is provided in the first discharge hole 190S.
[0112] The first muffler chamber 180S is one annularly communicable
chamber and a part of an intermediate communicating path
communicating a discharge side of the first compressing section 12S
with the interior of the compressor housing 10. The first muffler
chamber 180S reduces pressure pulsation of the discharged cooling
medium.
[0113] Furthermore, a first discharge valve holding member 201S as
well as the first discharge valve 200S is fixed on the first
discharge valve 200S by a rivet so as to restrict a deflection
opening amount of the first discharge valve 200S.
[0114] As shown in FIG. 14, a second muffler cover 170T is disposed
above the second end plate 160T and a second muffler chamber 180T
is formed between the second muffler cover 170T and the second end
plate 160T. A second discharge hole 190T communicating the second
compression chamber 133T of the second cylinder 121T with the
second muffler chamber 180T is provided in the second end plate
160T near the second vane 127T and a second discharge valve 200T
preventing backflow of the compressed cooling medium is provided in
the second discharge hole 190T.
[0115] Furthermore, a second discharge valve holding member 201T as
well as the second discharge valve 200T is fixed by a rivet so as
to restrict a deflection opening amount of the second discharge
valve 200T. The second muffler chamber 180T reduces pressure
pulsation of the discharged cooling medium.
[0116] The first cylinder 121S, the first end plate 160S, the first
muffler cover 170S, the second cylinder 121T, the second end plate
160T, the second muffler cover 170T, and the intermediate partition
plate 140 are integrally fastened by a bolt that is not shown.
Among the integrally fastened constituent elements of the
compressing section 12, an outer peripheral portion of the second
end plate 160T is fixedly bonded to the compressor housing 10 by
spot welding to thereby fix the compressing section 12 to the
compressor housing 10.
[0117] As shown in FIG. 14, first and second through holes 101 and
102 are provided in an outer circumferential wall of the
cylindrical compressor housing 10 to be axially away from each
other in ascending order from a lower portion. An accumulator 25T
formed of an independent and cylindrical airtight container is
arranged outside of the compressor housing 10 and held by an
accumulator holder 251 and an accumulator band 253.
[0118] A system connecting pipe 255 connecting the accumulator 25T
to a low-pressure side of a refrigerating cycle is provided in a
central portion of a top surface of the accumulator 25T. First and
second connecting pipes 31S and 31T each having one end extending
toward an upper portion of an interior of the accumulator 25T and
the other end connected to the other end of first and second
suction pipes 104 and 105 are connected to bottom through holes 257
provided at a bottom of the accumulator 25T, respectively.
[0119] The first and second connecting pipes 31S and 31T
introducing a low-pressure cooling medium of the refrigerating
cycle to the first and second compressing sections 12S and 12T via
the accumulator 25T are connected to first and second suction holes
135S and 135T of the first and second cylinders 121S and 121T via
the first and second through holes 101 and 102 and the first and
second suction pipes 104, respectively. Namely, the first and
second suction holes 135S and 135T communicate with the
low-pressure side of the refrigerating cycle in parallel.
[0120] Discharge portions of the first and second compressing
sections 12S and 12T communicate with the interior of the
compressor housing 10 via the first and second muffler chambers
180S and 180H, respectively. Accordingly, the first and second
discharge holes 190S and 190T communicating the first and second
compression chambers 133S and 133T of the first and second
cylinders 121S and 121T with the first and second muffler chambers
180S and 180H are provided in the first and second end plates 160S
and 160T, and the first and second discharge valves 200S and 200T
preventing backflow of the compressed cooling medium are disposed
in the first and second discharge holes 190S and 190T,
respectively.
[0121] A discharge pipe 107 connected to a high-pressure side of
the refrigerating cycle and discharging the high-pressure cooling
medium toward the high-pressure side of the refrigerating cycle is
connected to a top of the compressor housing 10. accordingly, the
first and second discharge holes 190S and 190T communicate with the
high-pressure side of the refrigerating cycle.
[0122] The compressor housing 10 is filled with lubricating oil
almost up to a height of the second cylinder 121T. The lubricating
oil circulates in the compressing section 12 by a vane pump, not
shown, attached to a lower portion of the rotary shaft 15 and seals
a portion defining the first and second working chambers 130S and
130T (compression spaces) for the compressed cooling medium by
lubrication of sliding components and narrow gaps.
[0123] First and second auxiliary discharge holes 190SS and 190TT
are provided at positions from the first and second vane grooves
128S and 128T by 230.degree. to 300.degree. in a direction of
revolution of the first and second pistons 125S and 125T along the
first and second cylinder inner walls 123S and 123T, respectively.
The arrangement is similar to that of the auxiliary discharge hole
190A according to the first embodiment since the two cylinders 121S
and 121T are arranged in parallel and equal in responsible pressure
ratio.
[0124] In the rotary compressor 3 according to the third
embodiment, the first and second auxiliary discharge holes 190SS
and 190TT are provided in the first and second end plates 160S and
160T of the first and second compressing sections 12S and 12T,
respectively. Alternatively, an auxiliary hole may be provided only
in one of the end plates.
[0125] Operation of the rotary compressor 3 described so far will
next be described. If the rotary compressor 3 is actuated, the
cooling medium flowing from the low-pressure side of the
refrigerating cycle into the accumulator 25T through the system
connecting pipe 255 is separated into a liquid cooling medium and a
gas cooling medium. Specifically, the liquid cooling medium is
accumulated in a lower portion of the accumulator 25T and the gas
cooling medium is accumulated in an upper portion thereof.
[0126] When the first and second pistons 125S and 125T revolve in
the first and second cylinders 121S and 121T and a volume of each
of the first and second suction chambers 131S and 131T increases,
the gas cooling medium in the accumulator 25T is absorbed into the
first and second suction chambers 131S and 131T of the first and
second compressing sections 12S and 12T through the first and
second connecting pipes 31S and 31T, the first and second suction
pipes 104, and the first and second suction holes 135S and 135T.
When the first and second pistons 125S and 125T revolve once, the
first and second suction chambers 131S and 131T are cut off from
the first and second suction holes 135S and 135T and changed over
to the first and second compression chambers 133S and 133T, and the
cooling medium is compressed in the first and second compression
chambers 133S and 133T.
[0127] If the pressure of the compressed cooling medium in each of
the first and second compression chambers 133S and 133T becomes
equal to the pressure of each of the first and second muffler
chambers 180S and 180T located downstream of the first and second
discharge valves 200S and 200T provided in the first and second
discharge hole 190S and 190T and the first and second auxiliary
discharge holes 190SS and 190TT, respectively, then the first and
second discharge valves 200S and 200T open, and the cooling medium
is discharged into the first and second muffler chambers 180S and
180T through the first and second discharge holes 190S and 190T and
the first and second auxiliary discharge holes 190SS and 190TT at
low flow resistance and the pressure pulsation causing noise is
reduced in the first muffler chamber 180S. The cooling medium is
discharged, as a high-pressure cooling medium, into the compressor
housing 10. Thereafter, the high-pressure cooling medium is fed to
an upper portion of the motor 11 through a core notch, not shown,
of the stator 111 of the motor 11 and gaps between a core and a
coil and discharged toward the high-pressure side of the
refrigerating cycle through the discharge pipe 107.
[0128] In the rotary compressor 3 according to the third
embodiment, the cooling medium is discharged into the compressor
housing 10 through the first and second discharge holes 190S and
190T and the first and second auxiliary discharge holes 190SS and
190TT at the low flow resistance. Therefore, the over-compression
loss can be reduced.
Fourth Embodiment
[0129] FIG. 16 is a top view of a compressing section of a rotary
compressor according to a fourth embodiment of the present
invention. FIG. 17 is a top view of the compressing section of the
rotary compressor according to the first embodiment for reference.
As shown in FIG. 16, in the rotary compressor according to the
fourth embodiment, a discharge groove 124 communicating with a
discharge hole 190 is provided in a region of a cylinder inner wall
123 corresponding to a position of the discharge hole 190 provided
in one end plate 160A but no discharge groove is provided in a
region of the cylinder inner wall 123 corresponding to a position
of an auxiliary discharge hole 190A.
[0130] If a discharge groove 124A is provided in the region of the
cylinder inner wall 123 corresponding to the position of the
auxiliary discharge hole 190A similarly to the rotary compressor 1
according to the first embodiment shown in FIG. 1, the cooling
medium compressed in the compression chamber 133 leaks into the
suction chamber 131 through narrow gaps between corners of the
discharge groove 124A and the piston 125 when the eccentric section
152 of the piston 125 passes through the position of the discharge
groove 124A.
[0131] As shown in the rotary compressor according to the fourth
embodiment, if a center of the auxiliary discharge hole 190A is
located inward of the cylinder inner wall 123 and no discharge
groove is provided in the region of the cylinder inner wall 123
corresponding to the position of the auxiliary discharge hole 190A,
the cooling medium leaking from the compression chamber 133 into
the suction chamber 131 can be reduced. Accordingly, efficiency can
be improved, as compared with the case in which the discharge
groove 124 is provided.
[0132] In the rotary compressor according to an embodiment of the
present invention, the auxiliary discharge hole different from the
discharge hole is provided in one end plate in which the discharge
hole is provided to increase a total area of the discharge hole.
Therefore, there is no need to work a concave portion for the
discharge hole, the valve seat around the discharge hole, and the
discharge valve to be provided on each of both end plates. It is
thereby possible to reduce working cost.
[0133] Although the invention has been described with respect to a
specific embodiment for a complete and clear disclosure, the
appended claims are not to be thus limited but are to be construed
as embodying all modifications and alternative constructions that
may occur to one skilled in the art that fairly fall within the
basic teaching herein set forth.
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