U.S. patent application number 12/531099 was filed with the patent office on 2010-02-18 for compressor capacity control operation mechanism and air conditioner provided with same.
This patent application is currently assigned to DAIKIN INDUSTRIES, LTD.. Invention is credited to Junichi Shimoda, Hisashi Takeichi, Takeomi Ukai, Shigetaka Wakisaka.
Application Number | 20100037642 12/531099 |
Document ID | / |
Family ID | 39830668 |
Filed Date | 2010-02-18 |
United States Patent
Application |
20100037642 |
Kind Code |
A1 |
Shimoda; Junichi ; et
al. |
February 18, 2010 |
COMPRESSOR CAPACITY CONTROL OPERATION MECHANISM AND AIR CONDITIONER
PROVIDED WITH SAME
Abstract
A compressor capacity control operation mechanism includes a
pilot valve (flow channel switching valve) having capillary tubes,
a suction branching pipe, an intermediate pipe, and a discharge
branching pipe. The suction branching pipe is connected to a first
capillary tube and branches off from a compressor suction pipe. The
intermediate pipe is connected to a second capillary tube and a
compressor cylinder intermediate part. The discharge branching pipe
is connected to a third capillary tube and branches off from a
compressor discharge pipe. Preferably, the suction, intermediate
and discharge branching pipes have larger diameters than the first
second and third capillary tubes. Also, the pilot valve preferably
has a flow channel configuration switchable between first and
second states in which the first, second and third capillary tubes
are connected differently in the first and second states.
Inventors: |
Shimoda; Junichi; (Osaka,
JP) ; Takeichi; Hisashi; ( Osaka, JP) ; Ukai;
Takeomi; (Osaka, JP) ; Wakisaka; Shigetaka;
(Osaka, JP) |
Correspondence
Address: |
GLOBAL IP COUNSELORS, LLP
1233 20TH STREET, NW, SUITE 700
WASHINGTON
DC
20036-2680
US
|
Assignee: |
DAIKIN INDUSTRIES, LTD.
Osaka-shi, Osaka
JP
|
Family ID: |
39830668 |
Appl. No.: |
12/531099 |
Filed: |
March 24, 2008 |
PCT Filed: |
March 24, 2008 |
PCT NO: |
PCT/JP2008/055367 |
371 Date: |
September 14, 2009 |
Current U.S.
Class: |
62/228.1 ;
62/498 |
Current CPC
Class: |
F04C 18/0215 20130101;
F25B 2500/01 20130101; F04C 28/26 20130101; F25B 41/20 20210101;
F25B 2600/02 20130101; F25B 49/022 20130101; F25B 13/00 20130101;
F25B 2313/02741 20130101; F25B 2600/0261 20130101 |
Class at
Publication: |
62/228.1 ;
62/498 |
International
Class: |
F25B 49/02 20060101
F25B049/02; F25B 1/00 20060101 F25B001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 28, 2007 |
JP |
2007-085368 |
Claims
1. A compressor capacity control operation mechanism configured to
be connected to a compressor and to control capacity of the
compressor; the compressor capacity control operation mechanism
comprising: a flow channel switching valve including a valve main
body having a flow channel configuration switchable between a first
state in which a first flow channel and a second flow channel are
connected and a third flow channel is not connected to either the
first flow channel or the second flow channel, and a second state
in which the second flow channel and the third flow channel are
connected and the first flow channel is not connected to either the
second flow channel or the third flow channel; with a first
capillary tube forming the first flow channel and extending from
the valve main body; a second capillary tube forming the second
flow channel and extending from the valve main body; and a third
capillary tube forming the third flow channel and extending from
the valve main body; a suction branching pipe branching off from a
suction pipe of the compressor and having a larger diameter than
the first capillary tube, the suction branching pipe being
connected to the first capillary tube; an intermediate pipe
connected to a cylinder intermediate part of the compressor and
having a larger diameter than the second capillary tube, the
intermediate pipe being connected to the second capillary tube; a
discharge branching pipe branching off from a discharge pipe of the
compressor and having a larger diameter than the third capillary
tube, the discharge branching pipe being connected to the third
capillary tube; and a fixing member having the flow channel
switching valve fixed thereto, and at least one of the suction
branching pipe, the intermediate pipe, and the discharge branching
pipe fixed thereto.
2. The compressor capacity control operation mechanism according to
claim 1, wherein the at least one of the suction branching pipe,
the intermediate pipe, and the discharge branching pipe fixed to
the fixing member being fixed to the fixing member in proximity to
the capillary tube connected thereto.
3. A compressor capacity control operation mechanism configured to
control compressor capacity; the compressor capacity control
operation mechanism comprising: a first pilot valve having four
connecting capillary tubes connected thereto, the first pilot valve
being operable as a first four-way switching valve; a suction
branching pipe connected to a first capillary tube of the four
connecting capillary tubes and branched off from a compressor
suction pipe; an intermediate pipe connected to a second capillary
tube of the four connecting capillary tubes and connected to a
compressor cylinder intermediate part; and a discharge branching
pipe connected to a third capillary tube of the four connecting
capillary tubes and branched off from a compressor discharge
pipe.
4. The compressor capacity control operation mechanism according to
claim 3, wherein a fourth capillary tube of the four connecting
capillary tubes is closed off.
5. An air conditioner including the compressor capacity control
operation mechanism according to claim 3, the air conditioner
further comprising: a vapor-compression main refrigerant circuit
including a compressor, a switching valve including a second pilot
valve operable as a second four-way switching valve, a first heat
exchanger, an expansion mechanism, and a second heat exchanger,
with the first pilot valve operable as the first four-way switching
valve being identical to the second pilot valve operable as the
second four-way switching valve.
6. An air conditioner including the compressor capacity control
operation mechanism according to claim 4, the air conditioner
further comprising: a vapor-compression main refrigerant circuit
including a compressor, a four-way switching valve, a first heat
exchanger, an expansion mechanism, and a second heat exchanger,
with the first pilot valve operable as the first four-way switching
valve being identical to the second pilot valve operable as the
second four-way switching valve.
7. The compressor capacity control operation mechanism according to
claim 3, further comprising a fixing member having the first pilot
valve fixed thereto, and at least one of the suction branching
pipe, the intermediate pipe, and the discharge branching pipe fixed
thereto; wherein the first pilot valve includes a valve main body
having a flow channel configuration switchable between a first
state in which the first and second capillary tubes are connected
and the third capillary tube is not connected to either the first
capillary tube or the second capillary tube, and a second state in
which the second and third capillary tubes are connected and the
first capillary tube is not connected to either the second
capillary tube or the third capillary tube; the suction branching
pipe has a larger diameter than the first capillary tube; the
intermediate pipe has a larger diameter than the second capillary
tube; the discharge branching pipe has a larger diameter than the
third capillary tube.
8. The compressor capacity control operation mechanism according to
claim 7, wherein the at least one of the suction branching pipe,
the intermediate pipe, and the discharge branching pipe fixed to
the fixing member is fixed to the fixing member in proximity to the
capillary tube connected thereto.
Description
TECHNICAL FIELD
[0001] The present invention relates to a compressor capacity
control operation mechanism and an air conditioner provided with
the same; and particularly relates to a compressor capacity control
operation mechanism connected to a compressor and capable of
controlling the capacity of the compressor, and to an air
conditioner provided with this mechanism.
BACKGROUND ART
[0002] Conventionally, there have been air conditioners including a
vapor-compression refrigerant circuit. Among air conditioners
including this type of refrigerant circuit, there are those that
use a configuration in which a compressor capacity control
operation circuit is connected to a compressor, thereby making it
possible to perform capacity control for switching the operating
state of the compressor between a full load operation for bringing
the discharge capacity to 100% with respect to the suction
capacity, and an unload operation for reducing the discharge
capacity relative to the suction capacity. The compressor capacity
control operation circuit has a bypass pipe for connecting a
cylinder intermediate part of the compressor and a suction pipe of
the compressor, an electromagnetic valve provided to the bypass
pipe and functioning as a two-way valve, a pilot pipe for
connecting the discharge pipe of the compressor and the cylinder
intermediate part of the compressor, and a capillary tube provided
to the pilot pipe; wherein the compressor can be controlled into
the full load operation by closing the electromagnetic valve, and
the compressor can be controlled into the unload operation by
opening the electromagnetic valve (for example, see Patent Document
1).
[0003] <Patent Document 1>
[0004] Japanese Laid-open Patent Application No. 9-72625
DISCLOSURE OF THE INVENTION
[0005] However, in the compressor capacity control operation
circuit described above, since merely the capillary tube is
provided to the pilot pipe, the refrigerant flowing from the
discharge pipe into the bypass pipe through the pilot pipe is added
to the refrigerant flowing from the cylinder intermediate part into
the suction pipe through the bypass pipe during the unload
operation, and a situation occurs in which some of the refrigerant
discharged from the compressor is needlessly bypassed to the
suction pipe, which is a cause of an increase in power consumption
in the compressor during the unload operation.
[0006] To overcome this problem, an electromagnetic valve
functioning as a two-way valve is provided not only to the bypass
pipe but to the pilot pipe as well, and the electromagnetic valve
provided to the bypass pipe is opened and the electromagnetic valve
provided to the pilot pipe is closed during the unload operation,
thereby making it possible to ensure that refrigerant does not flow
from the discharge pipe into the bypass pipe through the pilot
pipe. However, in this case, the compressor capacity control
operation circuit requires two electromagnetic valves functioning
as two-way valves, and the cost increases.
[0007] An object of the present invention is to provide a
compressor capacity control operation mechanism and an air
conditioner provided with this mechanism, wherein cost increases
can be prevented and the capacity of the compressor can be
controlled in the same manner as in a case of using two two-way
valves.
[0008] A compressor capacity control operation mechanism according
to a first aspect of the present invention is a compressor capacity
control operation mechanism that is connected to a compressor and
is capable of controlling the capacity of the compressor,
comprising a flow channel switching valve, a suction branching
pipe, an intermediate pipe, a discharge branching pipe, and a
fixing member. The flow channel switching valve has a valve main
body, a first capillary tube, a second capillary tube, and a third
capillary tube. The valve main body has the same function as when
two two-way valves are used to form a flow channel configuration
capable of switching between a first state in which a first flow
channel and a second flow channel are connected and a third flow
channel is not connected to either the first or second flow
channel, and a second state in which the second flow channel and
the third flow channel are connected and the first flow channel is
not connected to either the second or third flow channel. The first
capillary tube constitutes the first flow channel and extends from
the valve main body. The second capillary constitutes the second
flow channel extends from the valve main body. A third capillary
tube constitutes the third flow channel and extends from the valve
main body. The suction branching pipe is a pipe that branches off
from a suction pipe of the compressor, is connected to the first
capillary tube, and has a larger diameter than the first capillary
tube. The intermediate pipe is a pipe connected to a cylinder
intermediate part of the compressor, connected to the second
capillary tube, and provided with a larger diameter than the second
capillary tube. The discharge branching pipe is a pipe that
branches off from a discharge pipe of the compressor, is connected
to the third capillary tube, and has a larger diameter than the
third capillary tube. The fixing member fixes the flow channel
switching valve and at least one of the suction branching pipe, the
intermediate pipe, and the discharge branching pipe.
[0009] Since the compressor capacity control operation mechanism is
configured using a valve having the first, second, and third
capillary tubes extending from the valve main body as the flow
channel switching valve, strength is reduced in the portion of the
first capillary tube connected to the suction branching pipe, the
portion of the second capillary tube connected to the intermediate
pipe, and the portion of the third capillary tube connected to the
discharge branching pipe.
[0010] In view of this, in the compressor capacity control
operation mechanism, excessive stress is prevented from acting on
the first, second, and third capillary tubes by fixing the flow
channel switching valve and at least one of the suction branching
pipe, the intermediate pipe, and the discharge branching pipe to
the fixing member. Thus, a compressor capacity control operation
mechanism can be provided, whereby the cost increase resulting from
the use of two two-way valves is prevented and the same compressor
capacity control is achieved as in the case of using two two-way
valves.
[0011] A compressor capacity control operation mechanism according
to a second aspect of the present invention is the compressor
capacity control operation mechanism according to the first aspect
of the present invention, wherein among the suction branching pipe,
the intermediate pipe, and the discharge branching pipe, one or
those fixed to the fixing member are fixed to the fixing member at
the portions in proximity to the corresponding capillary tubes.
[0012] In this compressor capacity control operation mechanism,
since one or those fixed to the fixing member among the suction
branching pipe, the intermediate pipe, and the discharge branching
pipe are fixed to the fixing member at the portions in proximity to
the corresponding capillary tubes, it is possible to reliably
prevent positional misalignment and the like in proximity to the
capillary tubes of the suction branching pipe, the intermediate
pipe, and the discharge branching pipe. The stress applied to the
first, second, and third capillary tubes can thereby be reliably
reduced.
[0013] A compressor capacity control operation mechanism according
to a third aspect of the present invention is a compressor capacity
control operation mechanism connected to a compressor and capable
of controlling the capacity of the compressor, the compressor
capacity control operation mechanism comprising a pilot valve for
use as a four-way switching valve having four connecting capillary
tubes, a suction branching pipe, an intermediate pipe, and a
discharge branching pipe. The suction branching pipe is connected
to a first capillary tube as one of the four connecting capillary
tubes and is branched off from a suction pipe of the compressor.
The intermediate pipe is connected to a second capillary tube as
one of the four connecting capillary tubes and is connected to a
cylinder intermediate part of the compressor. The discharge
branching pipe is connected to a third capillary tube as one of the
four connecting capillary tubes and is branched off from a
discharge pipe of the compressor.
[0014] In this compressor capacity control operation mechanism,
since the pilot valve for use as a four-way switching valve is used
instead of two two-way valves, it is possible to provide a
compressor capacity control operation mechanism whereby the cost
increase resulting from the use of two two-way valves is prevented,
and the same compressor capacity control is achieved as in the case
of using two two-way valves.
[0015] A compressor capacity control operation mechanism according
to a fourth aspect of the present invention is the compressor
capacity control operation mechanism according to the third aspect
of the present invention, wherein a fourth capillary tube as one of
the four connecting capillary tubes is closed off.
[0016] In this compressor capacity control operation mechanism, the
configuration is simplified because the same flow channel
configuration as one configured from two two-way valves can be
achieved by a simple process of closing off one of the four
connecting capillary tubes of the pilot valve for use as a four-way
switching valve.
[0017] An air conditioner according to a fifth aspect of the
present invention comprises a vapor-compression main refrigerant
circuit including the compressor, a four-way switching valve, a
first heat exchanger, an expansion mechanism, and a second heat
exchanger; and the compressor capacity control operation mechanism
according to the third or fourth aspect of the present invention;
wherein the same valve as a pilot valve for use as a four-way
switching valve constituting the four-way switching valve is used
as the pilot valve for use as a four-way switching valve.
[0018] In this air conditioner, components can be shared, thereby
contributing to reducing the cost of the entire air conditioner,
because the pilot valve for use as a four-way switching valve used
in the compressor capacity control operation mechanism is the same
pilot valve for use as a four-way switching valve constituting the
four-way switching valve included in the main refrigerant
circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a schematic configuration diagram of an air
conditioner in which a compressor capacity control operation
mechanism according to an embodiment of the present invention is
used.
[0020] FIG. 2 is a perspective view showing the schematic internal
structure of an outdoor unit.
[0021] FIG. 3 is a schematic longitudinal cross-sectional view
showing the structure of part A in FIG. 1 (i.e., the structure of a
compressor and a compressor capacity control operation
circuit).
EXPLANATION OF THE REFERENCE SIGNS
[0022] 1 Air conditioner [0023] 22 Compressor [0024] 23 Four-way
switching valve [0025] 24 Outdoor heat exchanger (first heat
exchanger) [0026] 25 Expansion valve (expansion mechanism) [0027]
41 Indoor heat exchanger (second heat exchanger) [0028] 28 Suction
pipe [0029] 30 Discharge pipe [0030] 79 Cylinder intermediate part
[0031] 87 Suction branching pipe [0032] 88 Intermediate pipe [0033]
89 Discharge branching pipe [0034] 90, 23b Pilot valve (flow
channel switching valve, pilot valve for use as a four-way
switching valve) [0035] 91, Valve main body [0036] 93a First
capillary tube [0037] 93b Second capillary tube [0038] 93c Third
capillary tube [0039] 93d Fourth capillary tube [0040] 98 Fixing
member
BEST MODE FOR CARRYING OUT THE INVENTION
[0041] Embodiments of the compressor capacity control operation
mechanism according to the present invention, and an air
conditioner comprising this mechanism are described herein below
with reference to the drawings.
(1) Configuration of Air Conditioner
Entire Configuration
[0042] FIG. 1 is a schematic configuration diagram of an air
conditioner 1 in which a compressor capacity control operation
mechanism according to an embodiment of the present invention is
used. In the present embodiment, the air conditioner 1 is an
apparatus used for cooling and heating a room interior, and is a
so-called separated type air conditioner comprising primarily an
outdoor unit 2, an indoor unit 4, and a first refrigerant
communication pipe 6 and a second refrigerant communication pipe 7
connecting the outdoor unit 2 and the indoor unit 4. Specifically,
in the present embodiment, the outdoor unit 2 and the indoor unit 4
are configured by being connected by the refrigerant communication
pipes 6, 7 constructed on site, after the outdoor and indoor units
are shipped to the site of installation and installed. A
refrigerant circuit 10 of the air conditioner 1 of the present
embodiment is configured by connecting the outdoor unit 2 and the
indoor unit 4 via the refrigerant communication pipes 6, 7.
[0043] <Indoor Unit>
[0044] Next, the configuration of the indoor unit 4 will be
described using FIG. 1.
[0045] The indoor unit 4 is connected to the outdoor unit 2 via the
first refrigerant communication pipe 6 and the second refrigerant
communication pipe 7, and the indoor unit 4 constitutes a part of
the refrigerant circuit 10. The indoor unit 4 primarily has an
indoor refrigerant circuit 10b constituting the part of the
refrigerant circuit 10. The indoor refrigerant circuit 10b
primarily has an indoor heat exchanger 41 as a second heat
exchanger.
[0046] In the present embodiment, the indoor heat exchanger 41 is a
heat exchanger that functions as a refrigerant heater during
cooling, and as a refrigerant cooler during heating. One end of the
indoor heat exchanger 41 is connected to the second refrigerant
communication pipe 7, and the other end is connected to the first
refrigerant communication pipe 6.
[0047] In the present embodiment, the indoor unit 4 comprises an
indoor fan 42 for taking indoor air into the unit and supplying the
air to the room interior after heat exchange has been conducted,
and the indoor unit 4 is capable of conducting heat exchange
between the indoor air and the refrigerant flowing through the
indoor heat exchanger 41. The indoor fan 42 is rotatably driven by
an indoor fan motor 42a.
[0048] The indoor unit 4 also comprises an indoor controller 43 for
controlling the operations of the components constituting the
indoor unit 4. The indoor controller 43 has a microcomputer, a
memory and the like provided in order to control the indoor unit 4,
and is designed so as to be capable of exchanging control signals
and the like with an outdoor controller 37 (described hereinafter)
of the outdoor unit 2.
[0049] <Outdoor Unit>
[0050] Next, the configuration of the outdoor unit 2 will be
described using FIGS. 1 through 3. FIG. 2 is a perspective view
showing the internal structure of the outdoor unit 2. FIG. 3 is a
schematic longitudinal cross-sectional view showing the structure
of part A in FIG. 1 (i.e., the structure of a compressor 22 and a
compressor capacity control operation circuit 35).
[0051] The outdoor unit 2 is connected to the indoor unit 4 via the
first refrigerant communication pipe 6 and the second refrigerant
communication pipe 7, and the outdoor unit 2 constitutes an outdoor
refrigerant circuit 10a as a part of the refrigerant circuit
10.
[0052] The outdoor unit 2 has a structure (a so-called trunk
structure) in which the interior of a unit casing 51 shaped as
substantially rectangular parallelepiped box is divided into an air
blower chamber S1 and a machinery chamber S2 by a vertically
extending partitioning plate 56, and the outdoor unit 2 primarily
has the unit casing 51, outdoor refrigerant circuit structural
components (described hereinafter) constituting the outdoor
refrigerant circuit 10a, an outdoor fan 36, and an electrical
component assembly (not shown in FIG. 2) which functions as an
outdoor controller 37 (see FIG. 1) for controlling the operations
of the components constituting the outdoor unit 2.
[0053] The unit casing 51 primarily has a bottom plate 52, a top
plate 53 (shown by chain double-dashed lines in FIG. 2), a front
plate 54 (shown by chain double-dashed lines in FIG. 2), a side
plate 55 (shown by chain double-dashed lines in FIG. 2), and a
partitioning plate 56.
[0054] The bottom plate 52 is a horizontally-long substantially
rectangular metal plate-shaped member constituting the bottom
surface portion of the unit casing 51. The peripheral edges of the
bottom plate 52 are folded upward. The outer surface of the bottom
plate 52 is provided with two fixing arms 57 fixed to the on-site
installation surface. The fixing arms 57 are metal plate-shaped
members having substantially U shapes in a front view of the unit
casing 51 and extending from the front of the unit casing 51 toward
the rear.
[0055] The top plate 53 is a horizontally-long substantially
rectangular metal plate-shaped member constituting the top surface
portion of the outdoor unit 2.
[0056] The front plate 54 is primarily a metal plate-shaped member
constituting the front surface portion and the front part of the
right-side surface of the unit casing 51, and the bottom part of
the front plate 54 is fixed to the bottom plate 52 by screws or the
like. Formed in the front plate 54 is a discharge port 54a for
blowing out air that has been taken into the air blower chamber S1
through suction ports (not shown) formed in the back surface and
left-side surface of the unit casing 51.
[0057] The side plate 55 is primarily a metal plate-shaped member
constituting the rear part of the right-side surface and the right
back surface portion of the unit casing 51, and the bottom part of
the side plate 55 is fixed to the bottom plate 52 by screws or the
like.
[0058] The partitioning plate 56 is a metal plate-shaped member
disposed on the bottom plate 52 and extending vertically, and is
disposed so as to partition the internal space in the unit casing
51 into two left and right spaces (i.e., the air blower chamber S1
and the machinery chamber S2). The bottom part of the partitioning
plate 56 is fixed to the bottom plate 52 by screws or the like.
[0059] Thus, the internal space of the unit casing 51 is divided
into the air blower chamber S1 and the machinery chamber S2 by the
partitioning plate 56. More specifically, the air blower chamber S1
is a space enclosed by the bottom plate 52, the top plate 53, the
front plate 54, and the partitioning plate 56; and the machinery
chamber S2 is a space enclosed by the bottom plate 52, the top
plate 53, the front plate 54, the side plate 55, and the
partitioning plate 56. An outdoor heat exchanger 24 and the outdoor
fan 36 are disposed in the air blower chamber S1, and the
compressor 22, a four-way switching valve 23, and other outdoor
refrigerant circuit structural components, as well as the
electrical component assembly (not shown) are disposed in the
machinery chamber S2, as will be described hereinafter. In the unit
casing 51, the interior of the machinery chamber S2 can be made
visible by removing the portion of the front plate 54 that faces
the machinery chamber S2.
[0060] The outdoor refrigerant circuit structural components
constituting the outdoor refrigerant circuit 10a include primarily
an accumulator 21, the compressor 22, the four-way switching valve
23, the outdoor heat exchanger 24 as a first heat exchanger, an
expansion valve 25 (not shown in FIG. 2) as an expansion mechanism,
a first stop valve 26, and a second stop valve 27. The outdoor heat
exchanger 24 is herein disposed in the air blower chamber S1, and
the outdoor refrigerant circuit structural components other than
the outdoor heat exchanger 24 are disposed in the machinery chamber
S2.
[0061] The accumulator 21 is a container for temporarily retaining
a low-pressure refrigerant circulating within the refrigerant
circuit 10 connected between the suction port of the compressor 22
and the four-way switching valve 23, and is disposed in the right
rear corner of the machinery chamber S2 in the present embodiment
(see FIG. 2). The outlet of the accumulator 21 is connected to the
suction port of the compressor 22 by a first suction pipe 28, and
the inlet of the accumulator 21 is connected to the four-way
switching valve 23 by a second suction pipe 29.
[0062] The compressor 22 is a compressor having the function of
taking in and compressing low-pressure refrigerant and discharging
the resulting high-pressure refrigerant, and is disposed in the
substantial center of the machinery chamber S2 in a plan view (see
FIG. 2) in the present embodiment, in a state in which the space
for accommodating the electrical component assembly (not shown in
FIG. 2) and the four-way switching valve 23 and other outdoor
refrigerant circuit structural components is opened on the upper
side. The discharge port of the compressor 22 is connected to the
four-way switching valve 23 by a discharge pipe 30. The internal
structure of the compressor 22 will be described hereinafter, as
will be the compressor capacity control operation circuit 35 (not
shown in FIG. 2) as a compressor capacity control operation
mechanism connected to the compressor 22. The compressor capacity
control operation circuit 35 and the components other than the
compressor capacity control operation circuit 35 in the refrigerant
circuit 10 are described separately below. In this description, the
components other than the compressor capacity control operation
circuit 35 in the refrigerant circuit 10 are referred to as the
main refrigerant circuit.
[0063] The four-way switching valve 23 is a valve for switching the
direction of refrigerant flow when switching between cooling and
heating; and the valve is capable of connecting the discharge port
of the compressor 22 with the outdoor heat exchanger 24 and the
accumulator 21 with the second stop valve 27 during cooling, and of
connecting the discharge port of the compressor 22 with the second
stop valve 27 and the accumulator 21 with the outdoor heat
exchanger 24 during heating. The four-way switching valve 23 is
connected to the outdoor heat exchanger 24 by a first refrigerant
pipe 31 (only partially shown in FIG. 2) and is connected to the
second stop valve 27 by a fourth refrigerant pipe 34. In the
present embodiment, the four-way switching valve 23 has a four-way
switching valve main component 23a, and a pilot valve 23b (not
shown in FIG. 1) connected to the four-way switching valve main
component 23a. The pilot valve 23b is referred to as a pilot valve
for use as a four-way switching valve for operating the four-way
switching valve main component 23a when the aforementioned switch
between cooling and heating is made, and the pilot valve 23b is
fixed to the four-way switching valve main component 23a (see FIG.
2).
[0064] In the present embodiment, the outdoor heat exchanger 24 is
a heat exchanger that functions as a refrigerant cooler using
outdoor air as a heat source during cooling, and as a refrigerant
heater using outdoor air as a heat source during heating. One end
of the outdoor heat exchanger 24 is connected to the first
refrigerant pipe 31 (only partially shown in FIG. 2) via a
plurality of branching pipes 24a (not shown in FIG. 2). The other
end of the outdoor heat exchanger 24 is connected to a second
refrigerant pipe 32 via a plurality of branching pipes 24b (not
shown in FIG. 2) and a flow distributor 24c (not shown in FIG. 2).
In the present embodiment, the outdoor heat exchanger 24 is a
cross-fin type fin-and-tube heat exchanger configured from a heat
transfer tube and numerous fins, and is disposed in the air blower
chamber S1. The outdoor heat exchanger 24 has an L shape in a plan
view, and is disposed along the left side surface and back surface
of the unit casing 51. A tube plate 24d is provided to the right
end of the outdoor heat exchanger 24.
[0065] In the present embodiment, the expansion valve 25 (not shown
in FIG. 2) is an electrical expansion valve capable of
depressurizing the high-pressure refrigerant cooled in the outdoor
heat exchanger 24 during cooling before the refrigerant is fed to
the indoor heat exchanger 41, and of depressurizing the
high-pressure refrigerant cooled in the indoor heat exchanger 41
during heating before the refrigerant is fed to the outdoor heat
exchanger 24. One end of the expansion valve 25 is connected to the
second refrigerant pipe 32. The other end of the expansion valve 25
is connected to the first stop valve 26 by a third refrigerant pipe
33.
[0066] The first stop valve 26 is a valve provided to the
connecting portion between the refrigerant pipe in the outdoor unit
2 (the third refrigerant pipe 33 in the present embodiment) the
first refrigerant communication pipe 6 (shown by chain
double-dashed lines in FIG. 2). The second stop valve 27 is a valve
provided to the connecting portion between the refrigerant pipe in
the outdoor unit 2 (the fourth refrigerant pipe 34 in the present
embodiment) connects with the second refrigerant communication pipe
7 (shown by chain double-dashed lines in FIG. 2). The second stop
valve 27 is connected to the four-way switching valve 23 by the
fourth refrigerant pipe 34.
[0067] The outdoor fan 36 is an air-blowing fan that functions so
as to take air into the air blower chamber S1 through suction ports
(not shown) formed in the left side surface and back surface of the
unit casing 51, and to blow the air from the discharge port 54a
formed in the front surface of the unit casing 51 after the air has
passed through the outdoor heat exchanger 24. In the present
embodiment, the outdoor fan 36 is a propeller fan and is disposed
downstream of the outdoor heat exchanger 24 in the air blower
chamber S1. The outdoor fan 36 is configured so as to be rotatably
driven by an outdoor fan motor 36a.
[0068] The electrical component assembly (not shown) is disposed in
the upper space of the machinery chamber S2, and the assembly has a
control board including a microcomputer or the like for performing
operation control, an inverter board, and various other electrical
components.
[0069] Next, the internal structure of the compressor 22 and the
compressor capacity control operation circuit 35 will be described
in detail.
[0070] In the present embodiment, the compressor 22 is a hermetic
compressor in which primarily a compression element 62, an Oldham
ring 73, a compressor motor 75, and a bottom main bearing 76 are
housed inside a casing 61, which is an upright cylindrical
container.
[0071] The casing 61 primarily has a substantially cylindrical core
plate 61a, a top panel 61b fixed by welding to the top end of the
core plate 61a, and a bottom panel 61c fixed by welding to the
bottom end of the core plate 61a.
[0072] The compression element 62 is a scroll-type compression
element primarily having a housing 63, a fixed scroll 64 disposed
above the housing 63, and an orbiting scroll 65 that meshes with
the fixed scroll 64. The housing 63 is fixed by press-fitting into
the core plate 61a in the external peripheral surface throughout
the entire circumferential direction. The interior of the casing 61
is thereby partitioned into a high-pressure space S3 at the lower
part of the housing 63 and a low-pressure space S4 at the upper
part of the housing 63. A housing concave part 63a recessed in the
center of the top surface and a bearing part 63b extending downward
from the center of the bottom surface are also formed in the
housing 63. A bearing hole 63c penetrating through the bearing part
63b in the vertical direction is formed therein, and a drive shaft
66 is rotatably fitted into the bearing hole 63c via a bearing 67.
The fixed scroll 64 primarily has a panel 64a, a spiral (involute)
wrap 64b formed on the bottom surface of the panel 64a, and a
second external peripheral wall 64c enclosing the wrap 64b. A
discharge channel 69 communicated with a compression chamber 68
(described hereinafter) and an expanding concave part 70
communicated with the discharge channel 69 are formed in the panel
64a. The discharge channel 69 is formed so as to extend vertically
in the middle portion of the panel 64a. The expanding concave part
70 is configured from a horizontally expanding concave part that is
recessed in the top surface of the panel 64a. A lid 71 is fixed by
a bolt 72 to the top surface of the fixed scroll 64 so as to close
off the expanding concave part 70. By covering up the expanding
concave part 70 with the lid 71, the expanding concave part 70 is
partitioned from the low-pressure space S4 (i.e., communicated with
the high-pressure space S3), forming a muffler space S5 composed of
an expansion chamber for muffling operation noises in the
compression element 62. The orbiting scroll 65 primarily has a
panel 65a, a spiraling (involute) wrap 65b formed on the top
surface of the panel 65a, a bearing part 65c formed in the bottom
surface of the panel 65a, and a groove 65d formed in both ends of
the panel 65a. The orbiting scroll 65 is supported on the housing
63 by fitting the Oldham ring 73 into the groove 65d. The top end
of the drive shaft 66 is also fitted into the bearing part 65c. The
orbiting scroll 65 is thus incorporated into the compression
element 62, whereby the orbiting scroll 65 revolves within the
housing 63 without rotating on its axis due to the rotation of the
drive shaft 66. The wrap 65b of the orbiting scroll 65 is meshed
with the wrap 64b of the fixed scroll 64, and the compression
chamber 68 is formed between the contact parts of the wraps 64b,
65b. The compression chamber 68 is designed so that the volume
between the wraps 64b, 65b constricts toward the center along with
the revolution of the orbiting scroll 65. A communication channel
74 is formed through the fixed scroll 64 and the housing 63 in the
compression element 62. The communication channel 74 is formed so
that a scroll-side channel 74a formed in the fixed scroll 64 and a
housing-side channel 74b formed in the housing 63 are communicated
with each other. The top end of the communication channel 74, i.e.,
the top end of the scroll-side channel 74a, opens into the
expanding concave part 70; and the bottom end of the communication
channel 74, i.e., the bottom end of the housing-side channel 74b,
opens into the high-pressure space S3 from the bottom end surface
of the housing 63.
[0073] The Oldham ring 73 is a member for preventing rotational
movement of the orbiting scroll 65 as described above, and is
fitted into an Oldham groove (not shown) formed in the housing
63.
[0074] In the present embodiment, the compressor motor 75 is a
motor whose frequency can be controlled by an inverter control
element or the like mounted on the electrical component assembly
(not shown), and the motor is disposed below the compression
element 62. The compressor motor 75 primarily has an annular stator
75a fixed to the internal wall surface of the casing 61, and a
rotor 75b rotatably housed at a slight gap (air gap channel) from
the internal peripheral side of the stator 75a. A copper wire is
wound around the stator 75a, and coil ends are formed above and
below. The rotor 75b is linked to the orbiting scroll 65 of the
compression element 62 by the vertically extending drive shaft
66.
[0075] The bottom main bearing 76 is disposed in a bottom space
below the compressor motor 75. The bottom main bearing 76 is fixed
to the core plate 61a, forms a bearing at the bottom end of the
drive shaft 66, and supports the drive shaft 66.
[0076] The top panel 61b of the casing 61 is provided with a
suction nozzle 77 running vertically through the low-pressure space
S4 and having an internal end fitted into the fixed scroll 64 to
form the suction port of the compressor 22. The core plate 61a of
the casing 61 is also provided with a discharge nozzle 78 whose
inside end opens into the high-pressure space S3 to form the
discharge port of the compressor 22.
[0077] Furthermore, the compressor capacity control operation
circuit 35 is connected to the compressor 22 of the present
embodiment to allow capacity to be controlled so that the operating
state is switched between a full load operation in which the
discharge capacity is 100% with respect to the suction capacity,
and an unload operation in which the discharge capacity is reduced
with respect to the suction capacity. A cylinder intermediate part
79 is provided in order to implement this type of capacity control.
The cylinder intermediate part 79 primarily has an unload channel
80, a valve hole 81, a bypass channel 82, a valve 83, a spring 84,
the above-described lid 71, and an intermediate nozzle 85.
[0078] The unload channel 80 is formed in the fixed scroll 64 so as
to extend vertically, and the bottom end of the unload channel is
communicated with the compression chamber 68.
[0079] The valve hole 81 is formed in the fixed scroll 64 so as to
extend upward from the top end of the unload channel 80, and the
top end of the valve hole 81 is covered by the lid 71.
[0080] The bypass channel 82 is a channel for guiding the
refrigerant from the compression chamber 68 to the low-pressure
space S4 during the unload operation by establishing communication
between the low-pressure space S4 and the compression chamber 68
via the unload channel 80 and the valve hole 81, thereby
substantially delaying the start of compression. The bypass channel
82 is formed in the fixed scroll 64 so as to cause the valve holes
81 to communicate with the low-pressure space S4.
[0081] The valve 83 is disposed in the valve hole 81 in a state of
being urged upward by the spring 84, and is designed to be capable
of moving vertically within the valve hole 81 due to the balance
between the urging force of the spring 84 and the pressure in an
operational pressure chamber 86 formed above the valve 83.
Therefore, the unload channel 80 and the bypass channel 82 become
divided by the valve 83 when the valve 83 has moved downward (i.e.,
the pressure in the operational pressure chamber 86 is greater than
the urging force of the spring 84), and the unload channel 80 and
the bypass channel 82 communicate with each other when the valve 83
has moved upward (i.e., the pressure in the operational pressure
chamber 86 is less than the urging force of the spring 84).
[0082] The intermediate nozzle 85 is provided so as to pass
vertically through the top panel 61b of the casing 61, the
low-pressure space S4, and the lid 71; and to be communicated with
the operational pressure chamber 86 of the valve hole 81. Thus, in
the compressor 2, the valve 83 is operated according to the
pressure applied to the operational pressure chamber 86 through the
intermediate nozzle 85, thereby forming a cylinder intermediate
part 79 capable of opening and closing the unload channel 80.
[0083] The compressor capacity control operation circuit 35 is
connected to the compressor 22 having this cylinder intermediate
part 79, as described above. The compressor capacity control
operation circuit 35 primarily has a suction branching pipe 87, an
intermediate pipe 88, a discharge branching pipe 89, and a pilot
valve 90 as a flow-channel switching valve, and is disposed in the
space between the compressor 22 and the four-way switching valve 23
placed one above the other in the present embodiment (not shown in
FIG. 2).
[0084] The suction branching pipe 87 is a refrigerant pipe that
branches off from the suction pipe 28 of the compressor 22, and is
smaller in diameter than the suction pipe 28 in the present
embodiment.
[0085] The intermediate pipe 88 is a refrigerant pipe connected to
the cylinder intermediate part 79 of the compressor 22 (more
specifically, the intermediate nozzle 85), and is substantially the
same in diameter as the intermediate nozzle 85 in the present
embodiment.
[0086] The discharge branching pipe 89 is a refrigerant pipe that
branches off from the discharge pipe 30 of the compressor 22, and
is smaller in diameter than the discharge pipe 30 in the present
embodiment.
[0087] In the present embodiment, the pilot valve 90 is a pilot
valve for use as a four-way switching valve, primarily having a
valve main body 91, an electromagnetic coil 92, and four connecting
capillary tubes 93a, 93b, 93c, 93d. The valve main body 91
primarily has a valve case 94, a valve body 95, and a plunger 96.
The valve case 94 is a substantially cylindrical member having a
hollow space in the interior, wherein four ports 94a, 94b, 94c, 94d
communicated with the interior space are formed in the external
periphery of the valve case 94, and an opening 94e through which
the plunger 96 is reciprocatingly inserted is formed in a portion
at one axial end. In the present embodiment, the second port 94b,
the first port 94a, and the fourth port 94d are disposed at
substantially equal intervals in the axial direction from a
position near the opening 94e, and the third port 94c is disposed
so as to face the first port 94a. The valve body 95 is disposed
inside the valve case 94 and is linked to the axially distal end of
the portion of the plunger 96 inserted into the valve case 94. In
the present embodiment, the valve body 95 has a bowl shape.
Inserting the plunger 96 deep into the valve case 94 causes the
valve body 95 to move away from the opening 94e, allowing the first
port 94a and the fourth port 94d to communicate with each other and
also the second port 94b and the third port 94c to communicate with
each other; and reducing the depth of the insertion of the plunger
96 in the valve case 94 causes the valve body 95 to move toward the
opening 94e, allowing the first port 94a and the second port 94b to
communicate with each other and also the third port 94c and the
fourth port 94d to communicate with each other. The electromagnetic
coil 92 is disposed so as to enclose the external periphery of the
portion of the plunger 96 protruding axially out of the valve case
94. In the present embodiment, in the nonconductive state, the
plunger 96 is inserted deep into the valve case 94, whereby the
valve body 95 moves away from the opening 94e, the first port 94a
and the fourth port 94d are brought in communication with each
other, and the second port 94b and the third port 94c are brought
in communication with each other; and in the conductive state, the
depth of the insertion of the plunger 96 into the valve case 94 is
reduced, whereby the valve body 95 moves toward the opening 94e,
the first port 94a and the second port 94b are brought in
communication with each other, and the third port 94c and the
fourth port 94d are brought in communication with each other. One
end of the first capillary tube 93a is connected to the first port
94a, and the other end is connected to the suction branching pipe
87, which is larger in diameter than the first capillary tube 93a.
One end of the second capillary tube 93b is connected to the second
port 94b, and the other end is connected to the intermediate pipe
88, which is larger in diameter than the second capillary tube 93b.
One end of the third capillary tube 93c is connected to the third
port 94c, and the other end is connected to the discharge branching
pipe 89, which is larger in diameter than the third capillary tube
93c. One end of the fourth capillary tube 93d is connected to the
fourth port 94d, and the other end is closed off. Thus, one of the
four connecting capillary tubes, the fourth capillary tube 93d, is
closed off, whereby the valve main body 91 of the pilot valve 90
has the same function as when two two-way valves are used to form a
flow channel configuration in which the suction branching pipe 87
and the first capillary tube 93a communicated with the first port
94a constitute a first flow channel, the intermediate pipe 88 and
the second capillary tube 93b communicated with the second port 94b
constitute a second flow channel, and the discharge branching pipe
89 and the third capillary tube 93c communicated with the third
port 94c constitute a third flow channel; in which case it is
possible to switch between a first state (corresponding to the
conductive state of the electromagnetic coil 92 in the present
embodiment) in which the first flow channel and the second flow
channel are connected and the third flow channel is not connected
to either the first or second flow channel, and a second state
(corresponding to the nonconductive state of the electromagnetic
coil 92 in the present embodiment) in which the second flow channel
and the third flow channel are connected and the first flow channel
is not connected to either the second or third flow channel. The
state of the pilot valve 90 in FIG. 3 corresponds to a case in
which the electromagnetic coil 92 is in the nonconductive state.
The solid lines associated with the pilot valve 90 in FIG. 1
correspond to a case in which the electromagnetic coil 92 is in the
nonconductive state, and the dashed lines associated with the pilot
valve 90 in FIG. 1 correspond to a case in which the
electromagnetic coil 92 is in the conductive state.
[0088] When the full load operation is performed, the
electromagnetic coil 92 is in the nonconductive state, whereby the
second port 94b and the third port 94c of the pilot valve 90 are
brought into communication with each other, and the first port 94a
is not communicated with either of the second or third ports 94b,
94c. The pressure of the cylinder intermediate part 79 in the
operational pressure chamber 86 thereby increases, and the unload
channel 80 and the bypass channel 82 are divided by the valve 83,
therefore allowing compression work to be performed without
delaying the start of compression. When the unload operation is
performed, the first port 94a and the second port 94b of the pilot
valve 90 are brought into communication with each other, and the
third port 94c is not communicated with either of the first or
second ports 94a, 94b. The pressure of the cylinder intermediate
part 79 in the operational pressure chamber 86 thereby decreases,
and the unload channel 80 and the bypass channel 82 are brought
into communication with each other, the refrigerant is guided into
the low-pressure space S4 from the compression chamber 68, and
compression work is therefore performed with a delay in the start
of compression.
[0089] Thus, since the compressor capacity control operation
circuit 35 of the present embodiment uses the pilot valve 90 for
the four-way switching valve instead of two two-way valves, the
cost increase from using two two-way valves can be prevented, and
the same capacity control for the compressor 22 can be achieved as
in the case of using two two-way valves. Moreover, when the pilot
valve 90 is given a flow channel configuration identical to a flow
channel configuration composed of two two-way valves, this is
achieved by a simple process of closing off one (the fourth
capillary tube 93d in the present embodiment) of the four
connecting capillary tubes 93a, 93b, 93c, 93d, and the
configuration is therefore simplified. In the present embodiment,
the valve used as the pilot valve 90 is the same as the pilot valve
23b for use as a four-way switching valve constituting the four-way
switching valve 23 included in the main refrigerant circuit, and
components can therefore be shared, thereby contributing to
reducing the cost of the entire air conditioner 1.
[0090] However, since the pilot valve 90 for use as a four-way
switching valve is used as a flow channel switching valve in the
compressor capacity control operation circuit 35 of the present
embodiment, a valve is used in which the first, second, and third
capillary tubes 93a, 93b, 93c extend from the valve main body 91.
Therefore, strength is reduced in the portion of the first
capillary tube 93a connected with the suction branching pipe 87, in
the portion of the second capillary tube 93b connected with the
intermediate pipe 88, and in the portion of the third capillary
tube 93c connected with the discharge branching pipe 89.
[0091] In view of this, in the compressor capacity control
operation circuit 35 of the present embodiment, the pilot valve 90
and at least one of the suction branching pipe 87, the intermediate
pipe 88, and the discharge branching pipe 89 (the intermediate pipe
88 and the discharge branching pipe 89 herein) are fixed to a
fixing member 98, thereby ensuring that excessive stress does not
act on the first, second, and third capillary tubes 93a, 93b, 93c,
and enabling the use of the pilot valve 90 for use as a four-way
switching valve. The fixing member 98 herein is a sheet-shaped
member made of sheet metal, and is disposed in the present
embodiment so as to at least face the connecting portion between
the second capillary tube 93b and the intermediate pipe 88 and the
connecting portion between the third capillary tube 93c and the
discharge branching pipe 89. In the pilot valve 90, the
electromagnetic coil 92 is fixed to the fixing member 98 by a band
member 97e. The intermediate pipe 88 and the discharge branching
pipe 89 are fixed to the fixing member 98 by band members 97b, 97c,
respectively. In the present embodiment, the pipes fixed to the
fixing member 98 among the suction branching pipe 87, the
intermediate pipe 88, and the discharge branching pipe 89 (the
intermediate pipe 88 and the discharge branching pipe 89 herein)
are fixed to the fixing member 98 by the portions thereof in
proximity to the corresponding capillary tubes 93b, 93c. Therefore,
positional misalignment or the like in the capillary tube
proximities of the suction branching pipe 87, the intermediate pipe
88, and the discharge branching pipe 89 can be reliably prevented,
whereby stress acting on the first, second, and third capillary
tubes 93a, 93b, 93c can be reliably reduced. In the present
embodiment, the connecting portion between the first capillary tube
93a and the suction branching pipe 87 is not fixed to the fixing
member 98, but at least one of the suction branching pipe 87, the
intermediate pipe 88, and the discharge branching pipe 89 is
preferably fixed to the fixing member 98. For example, the suction
branching pipe 87 may be fixed to the fixing member 98 by a band
member similar to the intermediate pipe 88 and the discharge
branching pipe 89, or any one of the suction branching pipe 87, the
intermediate pipe 88, and the discharge branching pipe 89 may be
fixed to the fixing member 98.
[0092] The outdoor controller 37 has a microcomputer, a memory and
the like provided in order to control the outdoor unit 2, and the
outdoor controller 37 is designed to be capable of exchanging
control signals or the like with the indoor controller 43 of the
indoor unit 4. Specifically, a controller as an operation control
means for performing operation control for the air conditioner 1 is
configured by the indoor controller 43 and the outdoor controller
37.
[0093] The outdoor refrigerant circuit 10a, the indoor refrigerant
circuit 10b, and the refrigerant communication pipes 6, 7 are
connected as described above to form the refrigerant circuit 10
that is capable of heating and cooling a room interior and that has
the main refrigerant circuit including the compressor 22, the
four-way switching valve 23, the outdoor heat exchanger 24 as a
first heat exchanger, the expansion valve 25 as an expansion
mechanism, and the indoor heat exchanger 41 as a second heat
exchanger, and also has the compressor capacity control operation
circuit 35 connected to the compressor 22 and used to enable the
capacity of the compressor 22 to be controlled. The air conditioner
1 of the present embodiment is designed to be capable of
controlling the devices of the outdoor unit 2 and the indoor unit 4
by a controller configured from the indoor controller 43 and the
outdoor controller 37.
(2) Operation of Air Conditioner
Operation During Full Load Operation
[0094] First, the operation during cooling will be described using
FIGS. 1 and 3.
[0095] During cooling, the four-way switching valve 23 is in the
state shown by the solid lines in FIG. 1; i.e., a state in which
the discharge side of the compressor 22 is connected to the outdoor
heat exchanger 24 and the suction side of the compressor 22 is
connected to the second stop valve 27. The degree of opening of the
expansion valve 25 is adjustable. The stop valves 26, 27 are in an
open state. Furthermore, the electromagnetic coil 92 of the pilot
valve 90 is in the nonconductive state.
[0096] When the compressor 22, the outdoor fan 36, and the indoor
fan 42 are started up while the refrigerant circuit 10 is in this
state, the low-pressure refrigerant is taken in by the compressor
22 and compressed to be a high-pressure refrigerant. Since the
electromagnetic coil 92 of the pilot valve 90 is in the
nonconductive state herein, the result is a state in which the
second port 94b and the third port 94c of the pilot valve 90 are
brought into communication with each other, and the first port 94a
is not communicated with either of the second or third ports 94b,
94c, whereby compression work is performed in the compressor 22
without delaying the start of compression, and a full load
operation is performed in which the discharge capacity is 100% with
respect to the suction capacity. The high-pressure refrigerant is
then fed via the four-way switching valve 23 to the outdoor heat
exchanger 24 functioning as a refrigerant cooler, heat exchange is
conducted between the refrigerant and outdoor air supplied by the
outdoor fan 36, and the refrigerant is cooled. The high-pressure
refrigerant cooled in the outdoor heat exchanger 24 is
depressurized by the expansion valve 25 to be a low-pressure
gas-liquid two-phase refrigerant, which is fed via the first stop
valve 26 and the first refrigerant communication pipe 6 to the
indoor unit 4. The low-pressure gas-liquid two-phase refrigerant
fed to the indoor unit 4 is heated through heat exchange with
indoor air in the indoor heat exchanger 41 functioning as a
refrigerant heater, and the refrigerant is thereby evaporated to be
a low-pressure refrigerant. The low-pressure refrigerant heated in
the indoor heat exchanger 41 is then fed via the second refrigerant
communication pipe 7 to the outdoor unit 2, and is again taken in
by the compressor 22 via the second stop valve 27, the four-way
switching valve 23, and the accumulator 21. Thus, cooling is
performed. The capacity of the compressor 22 during the full load
operation is controlled primarily by frequency control of the
compressor motor 75.
[0097] Next, the operation during heating will be described using
FIGS. 1 and 3.
[0098] During heating, the four-way switching valve 23 is in the
state shown by the dashed lines in FIG. 1; i.e., a state in which
the discharge side of the compressor 22 is connected to the second
stop valve 27, and the suction side of the compressor 22 is
connected to the outdoor heat exchanger 24. The degree of opening
of the expansion valve 25 is adjustable. The stop valves 26, 27 are
in an open state. Furthermore, the electromagnetic coil 92 of the
pilot valve 90 is in the nonconductive state.
[0099] When the compressor 22, the outdoor fan 36, and the indoor
fan 42 are started up while the refrigerant circuit 10 is in this
state, the low-pressure refrigerant is taken in by the compressor
22 and compressed to be a high-pressure refrigerant. Since the
electromagnetic coil 92 of the pilot valve 90 is in the
nonconductive state herein, the result is a state in which the
second port 94b and the third port 94c of the pilot valve 90 are
brought into communication with each other and the first port 94a
is not communicated with either of the second or third ports 94b,
94c, whereby compression work is performed in the compressor 22
without delaying the start of compression, and a full load
operation is performed in which the discharge capacity is 100% with
respect to the suction capacity. The high-pressure refrigerant is
then fed via the four-way switching valve 23, the second stop valve
27, and the second refrigerant communication pipe 7 to the indoor
unit 4. The high-pressure refrigerant fed to the indoor unit 4 is
then cooled through heat exchange with indoor air in the indoor
heat exchanger 41 functioning as a refrigerant cooler, and the
refrigerant is then fed via the first refrigerant communication
pipe 6 to the outdoor unit 2. The high-pressure refrigerant fed to
the outdoor unit 2 is depressurized by the expansion valve 25 to be
a low-pressure gas-liquid two-phase refrigerant, and then flows
into the outdoor heat exchanger 24 functioning as a refrigerant
heater. The low-pressure gas-liquid two-phase refrigerant that has
flowed into the outdoor heat exchanger 24 is heated through heat
exchange with outdoor air supplied by the outdoor fan 36, the
refrigerant is thereby evaporated to be a low-pressure refrigerant,
and the refrigerant is taken back into the compressor 22 via the
four-way switching valve 23 and the accumulator 21. Thus, heating
is performed. The capacity of the compressor 22 during the full
load operation is controlled primarily by performing frequency
control of the compressor motor 75.
[0100] <Action During Unload Operation>
[0101] The full load operation as described above is performed in
areas in which the operating efficiency of the refrigeration cycle
is comparatively favorable in cases in which the ratio of the
pressure of the high-pressure refrigerant with respect to the
pressure of the low-pressure refrigerant in the refrigeration cycle
is suppressed at a predetermined range or lower, or in cases in
which the frequency of the compressor motor 75 is in a
comparatively high range. Therefore, there are many cases in which
controlling the frequency of the compressor motor 75 is sufficient
to control the capacity of the compressor 22.
[0102] However, in cases in which the ratio of the pressure of the
high-pressure refrigerant with respect to the pressure of the
low-pressure refrigerant in the refrigeration cycle exceeds the
predetermined range, or in cases in which the frequency of the
compressor motor 75 is in a low range, conditions arise in which
the capacity of the compressor 22 cannot be sufficiently controlled
merely by controlling the frequency of the compressor motor 75, or
the operation is performed in an area of poor operating
efficiency.
[0103] In view of this, the electromagnetic coil 92 of the pilot
valve 90 is switched to the conductive state in such a case,
creating a state in which the first port 94a and the second port
94b of the pilot valve 90 are brought into communication with each
other, and the third port 94c is not communicated with either of
the first or second ports 94a, 94b, thereby creating a state in
which the unload channel 80 and the bypass channel 82 are
communicated with each other and the refrigerant is guided from the
compression chamber 68 to the low-pressure space S4. Compression
work is thereby performed in the compressor 22 in a state in which
the start of compression is delayed, an unload operation is
performed in which the discharge capacity is reduced with respect
to the suction capacity, and an operation in the state in which the
compressor motor 75 has a low frequency is avoided.
[0104] The operating efficiency can thereby be prevented as much as
possible from decreasing, even in cases in which the ratio of the
pressure of the high-pressure refrigerant with respect to the
pressure of the low-pressure refrigerant in the refrigeration cycle
exceeds the predetermined range, or in cases in which the frequency
of the compressor motor 75 is in a low range. Moreover, the pilot
valve 90 is designed so that there are no situations in which some
of the refrigerant discharged from the compressor 22 is needlessly
bypassed to the suction pipe 28 from the discharge pipe 30, similar
to a case of using two two-way valves, and increases in power
consumption in the compressor 22 during the unload operation can
therefore be suppressed. Furthermore, when switching between the
full load operation and the unload operation, unlike a case of
using two two-way valves, the number of electrical wires can be
reduced and the control specifics can be simplified because it is
only necessary to control just the pilot valve 90.
(3) Other Embodiments
[0105] An embodiment of the present invention was described above
with reference to the drawings, but the specific configuration is
not limited to this embodiment, and modifications can be made
within a range that does not deviate from the scope of the
invention.
[0106] <A>
[0107] In the embodiment described above, the fourth capillary tube
93d was closed off among the four connecting capillary tubes 93a to
93d of the pilot valve 90, but the present invention is not limited
to this option, and any one of the four connecting capillary tubes
93a to 93d can be can be closed off. In this case, the capillary
tubes connected to the suction branching pipe 87, the intermediate
pipe 88, and the discharge branching pipe 89 are changed according
to the closed off capillary tube, whereby the pilot valve 90
preferably has the same flow channel configuration as one
configured from two two-way valves, similar to the embodiment
described above.
[0108] <B>
[0109] In the embodiment described above, a scroll compressor was
used as the compressor 22, and the compressor motor 75 was disposed
in the high-pressure space S3 filled with high-pressure
refrigerant, but the present invention is not limited to this
option, and a rotary compressor or another such compressor may be
used, and the compressor motor 75 may be disposed in a space filled
with low-pressure refrigerant.
[0110] <C>
[0111] In the embodiment described above, the outdoor unit 2 had a
design in which the interior of the unit casing 51 was divided by
the partitioning plate 56 into the air blower chamber S1 and the
machinery chamber S2 and the air taken into the unit casing 51 was
blown out from the front surface of the unit casing 51, but the
present invention is not limited to this option, and another type
of outdoor unit may be used, such as an outdoor unit having a
design in which air taken into the unit casing is blown out from
the top surface of the unit casing. In the embodiment described
above, the air conditioner 1 was a so-called paired and separated
type air conditioner in which one indoor unit 4 was connected to
one outdoor unit 2, but other types of air conditioner may also be
used, such as a remote-condenser type air conditioner or a
multi-type air conditioner in which a plurality of indoor units are
connected to one or more outdoor unit.
INDUSTRIAL APPLICABILITY
[0112] Utilizing the present invention makes it possible to provide
a compressor capacity control operation mechanism and an air
conditioner comprising the mechanism wherein cost increases can be
prevented and the capacity of the compressor can be controlled in
the same manner as in a case of using two two-way valves.
* * * * *