U.S. patent application number 12/516718 was filed with the patent office on 2010-03-18 for reciprocating compressor for refrigerator.
Invention is credited to Kiyoshi Terauchi.
Application Number | 20100068085 12/516718 |
Document ID | / |
Family ID | 39467942 |
Filed Date | 2010-03-18 |
United States Patent
Application |
20100068085 |
Kind Code |
A1 |
Terauchi; Kiyoshi |
March 18, 2010 |
Reciprocating Compressor for Refrigerator
Abstract
The present invention provides a reciprocating compressor for a
refrigerator capable of restraining an increase in temperature of a
refrigerant discharged and increasing refrigerant compression
efficiency. The compressor according to the present invention
includes a housing (16) having cylinder bores (30), pistons (32)
fitted in the respective cylinder bores (30) and each capable of
reciprocating motion in the bore (30), an intermediate pressure
chamber (68) arranged in the housing (16) and supplied with the
refrigerant at a low temperature from a gas-liquid separator (10)
of the refrigerator, and a rotary valve (78) arranged between the
chambers (33, 68). The rotary valve (78) is rotated in association
with a main shaft (34) of the compressor and opened to inject the
low-temperature refrigerant into each compression chamber (33) from
the intermediate pressure chamber (68) while the compression
chamber (33) is in a process of compressing the refrigerant.
Inventors: |
Terauchi; Kiyoshi; (Gunma,
JP) |
Correspondence
Address: |
COHEN, PONTANI, LIEBERMAN & PAVANE LLP
551 FIFTH AVENUE, SUITE 1210
NEW YORK
NY
10176
US
|
Family ID: |
39467942 |
Appl. No.: |
12/516718 |
Filed: |
November 30, 2007 |
PCT Filed: |
November 30, 2007 |
PCT NO: |
PCT/JP2007/073169 |
371 Date: |
May 28, 2009 |
Current U.S.
Class: |
417/515 |
Current CPC
Class: |
F25B 1/10 20130101; F04B
39/06 20130101; F04B 27/1081 20130101; F25B 2400/23 20130101; F25B
1/02 20130101; F25B 2400/13 20130101; F04B 27/1018 20130101; F04B
39/062 20130101 |
Class at
Publication: |
417/515 |
International
Class: |
F04B 7/06 20060101
F04B007/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 1, 2006 |
JP |
2006-325544 |
Claims
1. A reciprocating compressor for a refrigerator, comprising: a
housing having cylinder bores pistons fitted in the respective
cylinder bores to define compression chambers in the respective
cylinder bores, said pistons each being capable of reciprocating
motion in their own cylinder bore and each repeating, by their
reciprocating motion, a process of sucking a refrigerant into their
own compression chamber, compressing the sucked refrigerant in the
compression chamber and discharging the compressed refrigerant from
the compression chamber so that the discharged refrigerant is
supplied to a refrigerant circulation path of the refrigerator, and
an introduction device arranged in said housing to allow an
intermediate refrigerant to be introduced from the refrigerant
circulation path into each compression chamber only for a
predetermined period of time while the compression chamber is in
the process of compressing the refrigerant, where the pressure of
the intermediate refrigerant is above the pressure of the
refrigerant being compressed in the compression chamber.
2. The reciprocating compressor for the refrigerator according to
claim 1, wherein the intermediate refrigerant allowed to be
introduced into each compression chamber by said introduction
device has a temperature lower than the temperature of the
refrigerant being compressed in the compression chamber.
3. The reciprocating compressor for the refrigerator according to
claim 1, wherein said introduction device includes an intermediate
pressure chamber defined in said housing and supplied with the
intermediate refrigerant from the refrigerant circulation path,
connection passages connecting the intermediate pressure chamber
and the respective compression chambers, and a valve associated
with the connection passages to open and close the connection
passages, where the valve opens each connection passage while the
corresponding compression chamber is in the process of compressing
the refrigerant and closes the connection passage before the
refrigerant being compressed reaches to the pressure of the
intermediate refrigerant in the intermediate pressure chamber.
4. The reciprocating compressor for the refrigerator according to
claim 3, wherein the valve is a rotary valve mechanically connected
to a main shaft of the compressor to rotate integrally with the
main shaft.
5. The reciprocating compressor for the refrigerator according to
claim 3, wherein the valve is a rotary valve caused to rotate by a
motor independent from a main shaft of the compressor.
6. The reciprocating compressor for the refrigerator according to
claim 3, wherein the valve is a solenoid-operated valve.
7. The reciprocating compressor for the refrigerator according to
claim 1, further comprising a variable displacement mechanism
capable of varying the amount of the compressed refrigerant
discharged, where said variable displacement mechanism includes a
swashplate.
8. The reciprocating compressor for the refrigerator according to
claim 1, wherein the refrigerant is carbon dioxide.
9. The reciprocating compressor for the refrigerator according to
claim 1, wherein the refrigerant includes a compound having
hydrocarbons containing one or more double bond between carbon
atoms.
Description
TECHNICAL FIELD
[0001] This invention relates to a reciprocating compressor for a
refrigerator, and particularly a compressor suited for a
refrigerator included in an automotive air conditioning system.
BACKGROUND ART
[0002] The reciprocating compressor of this type includes a
cylinder block having a plurality of cylinder bores, pistons fitted
in the respective cylinder bores to be capable of reciprocating
within them, each piston defining a compression chamber within its
own cylinder bore, and a main shaft rotatable to cause the pistons
to reciprocate within their own cylinder bores. The rotation of the
main shaft causes the respective pistons to reciprocate within
their own cylinder bores successively. By reciprocating in this
manner, each piston repeats a process of sucking a refrigerant into
its compression chamber, compressing the refrigerant in the
compression chamber and discharging the compressed refrigerant from
the compression chamber (Patent Document 1).
Patent Document 1: Japanese Patent Application KOKAI Publication
2001-027177
DISCLOSURE OF THE INVENTION
Problem to be Solved by the Invention
[0003] Generally, an alternative for chlorofluorocarbon, called
R134a, is used as a refrigerant in the automotive air conditioning
system, specifically in the refrigerator thereof. Such alternatives
for chlorofluorocarbon have, however, a very high GWP (Global
Warming Potential). Specifically, the aforementioned alternative
for chlorofluorocarbon has a GWP of about 1300.
[0004] Thus, the refrigerator of Patent Document 1 uses carbon
dioxide (CO.sub.2) having a low GWP as a refrigerant, in place of
the aforementioned alternative for chlorofluorocarbon. In recent
years, use of new alternative refrigerants having a low GWP has
been proposed. Such new alternative refrigerants include a double
bond (R1234yf etc., for example).
[0005] The temperature of the CO.sub.2 refrigerant compressed by
the compressor, namely the discharge temperature thereof, is higher
than that of R134a compressed by the compressor. Specifically, the
discharge temperature of the CO.sub.2 refrigerant is above
150.degree. C., so that the compressor undergoes a large thermal
load. On the other hand, the discharge temperature of the
aforementioned new alternative refrigerants compressed by the
compressor is held down at the same level as that of R134a. The new
alternative refrigerants including a double bond is however liable
to decomposition at their discharge temperature, since the double
bond is easily broken in high-temperature use conditions.
[0006] The primary object of the present invention is to provide a
reciprocating compressor for a refrigerator capable of restraining
an increase in discharge temperature of the refrigerant and
increasing refrigerant compression efficiency.
Means for Solving the Problem
[0007] In order to achieve the above object, a reciprocating
compressor for a refrigerator according to the present invention
comprises a housing having cylinder bores; pistons fitted in the
respective cylinder bores to define compression chambers in the
respective cylinder bores, the pistons each being capable of
reciprocating motion in their own cylinder bore and each repeating,
by their reciprocating motion, a process of sucking a refrigerant
into their own compression chamber, compressing the sucked
refrigerant in the compression chamber and discharging the
compressed refrigerant from the compression chamber so that the
discharged refrigerant is supplied to a refrigerant circulation
path of the refrigerator; and an introduction device arranged in
the housing to allow an intermediate refrigerant to be introduced
from the refrigerant circulation path into each compression chamber
only for a predetermined period of time while the compression
chamber is in a process of compressing the refrigerant, where the
pressure of the intermediate refrigerant is above the pressure of
the refrigerant being compressed in the compression chamber.
[0008] It is desirable that the intermediate refrigerant allowed to
be introduced into each compression chamber by the introduction
device has a temperature lower than the temperature of the
refrigerant being compressed within the compression chamber.
[0009] Specifically, it may be arranged such that the introduction
device includes an intermediate pressure chamber defined in the
housing and supplied with the intermediate refrigerant from the
refrigerant circulation path; connection passages connecting the
intermediate pressure chamber and the respective compression
chambers; and a valve associated with the connection passages to
open and close the connection passages, where the valve opens each
connection passage while the corresponding compression chamber is
in the process of compressing the refrigerant and closes the
connection passage before the refrigerant being compressed reaches
to the pressure of the intermediate refrigerant in the intermediate
pressure chamber.
[0010] In the above-described reciprocating compressor, the valve
is opened while each compression chamber is in the process of
compressing the refrigerant. At the time that the valve is opened,
the pressure of the intermediate refrigerant in the intermediate
pressure chamber is higher than the pressure of the refrigerant
being compressed in the compression chamber. Thus, when the valve
is opened, the intermediate refrigerant is injected into the
compression chamber. At this time, the temperature of the
intermediate refrigerant is lower than the temperature of the
refrigerant being compressed within the compression chamber.
Consequently, by mixing with the intermediate refrigerant, the
refrigerant being compressed within the compression chamber is
cooled.
[0011] This restrains an increase in temperature of the refrigerant
discharged from the compressor, therefore, allows carbon dioxide
and the aforementioned refrigerants containing a compound with a
double bond to be used as a refrigerant, which contributes much to
prevention of global warming. Further, injecting the intermediate
refrigerant into the compression chamber while the compression
chamber is in the process of compressing the refrigerant leads to
an increase in refrigerant compression efficiency, which results in
a great improvement in energy efficiency of the refrigerator.
[0012] The aforementioned valve may be a rotary valve mechanically
connected to a main shaft of the compressor to rotate integrally
with the main shaft, or a rotary valve caused to rotate by a motor
independent from the main shaft, or a solenoid-operated valve.
[0013] The compressor may further comprise a variable displacement
mechanism capable of varying the amount of the compressed
refrigerant discharged, where the variable displacement mechanism
includes a swashplate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a diagram showing a schematic configuration of a
refrigerator,
[0015] FIG. 2 is a cross-sectional view showing details of a
compressor indicated in FIG. 1,
[0016] FIG. 3 is a diagram showing a variant of a rotary valve,
and
[0017] FIG. 4 is a diagram showing a solenoid-operated on-off
valve.
BEST MODE OF CARRYING OUT THE INVENTION
[0018] A refrigerator shown in FIG. 1 is incorporated in an
automotive air conditioning system and has a refrigerant
circulation path 2. A compressor 4, a condenser 6, a first
expansion valve 8, a gas-liquid separator 10, a second expansion
valve 12 and an evaporator 14 in this order are inserted in the
circulation path 2. The compressor 4 compresses a refrigerant and
discharges the compressed refrigerant, and the refrigerant
discharged is supplied to the condenser 6 and then circulates along
the circulation path 2.
[0019] The circulation path 2 includes a high-pressure section
2.sub.H extending from a discharge port 4d of the compressor 4 to
the first expansion valve 8 via the condenser 6, and a low-pressure
section 2.sub.L extending from the first expansion valve 8 to an
intake port 4s of the compressor 4 via the gas-liquid separator 10,
the second expansion valve 12 and the evaporator 14.
[0020] FIG. 2 shows details of the compressor 4.
[0021] The compressor 4 is a variable-displacement reciprocating
compressor and includes a housing 16. When viewed from the left
side in FIG. 2, the housing 16 has an end plate 18, a center casing
20 and a cylinder head 22, and these end plate 18, center casing 20
and cylinder head 22 are integrally joined together.
[0022] The center casing 20 defines a crank chamber 24 therein. The
crank chamber 24 is located between the end plate 18 and a cylinder
block 26 which forms an end wall of the center casing 20.
[0023] Within the center casing 20, a compression unit 28 is
arranged. The compression unit 28 will be described below in
detail.
[0024] The cylinder block 26 has a plurality of cylinder bores 30
formed therein. The cylinder bores 30 are arranged circularly
around the axis of the cylinder block 26 at equal intervals and
each passes through the cylinder block 26. Pistons 32 are slidably
fitted into the respective cylinder bores 30. The pistons 32 each
define a compression chamber 33 within their own cylinder bore 30.
FIG. 2 shows only one cylinder bore 30 and one piston 32.
[0025] A main shaft 34 is arranged in the crank chamber 24. The
main shaft 34 is coaxial with the cylinder block 26 and has inner
and outer ends. The inner end of the main shaft 34 is located in
the cylinder block 26 and rotatably supported to the cylinder block
26 through a bearing 36. The outer end of the main shaft 34 is
located outside the housing 16. Thus, the main shaft 34 penetrates
the end plate 18 and is supported to the end plate 18 by means of a
bearing 38 and a seal unit 40. The outer end of the main shaft 34
is connected to an automotive engine through a power transmission
path (not shown). Thus, drive power transmitted from the engine to
the main shaft 34 causes the main shaft 34 to rotate in one
direction.
[0026] A rotor 42 is mounted on the main shaft 34. The rotor 42 is
arranged within the crank chamber 24. The rotor 42 rotates
integrally with the main shaft 34 and is rotatably supported on the
end plate 18 through a thrust bearing 44.
[0027] Also a swashplate 46 is arranged within the crank and
surrounds the main shaft 34. The swashplate 46 and the rotor 42 are
connected together by means of a link 48. The link 48 allows the
swashplate 46 to tilt with respect to the main shaft 34 so that the
angle of inclination of the swashplate 46 can vary. Further, a
wobble plate 54 is supported to the swashplate 46 through a radial
bearing 50 and a thrust bearing 52. The wobble plate 54 is
prevented from rotating on its axis by a rotation prevention
mechanism (not shown).
[0028] The wobble plate 54 is connected to the pistons 32 through
piston rods 56, respectively. Each piton rod 56 has a ball joint
57a, 57b at either end. The ball joint 57a connects the wobble
plate 54 and the piston rod 56 together, while the ball joint 57b
connects the piston rod 56 and the piston 32 together. Thus, when
the main shaft 34 is rotated, the rotation of the main shaft 34 is
converted into reciprocating motion of the pistons 32 by means of
the rotor 42, the swashplate 46, the wobble plate 54 and the piston
rods 56.
[0029] As clear from FIG. 2, a valve plate 58 is interposed between
the cylinder block 26 and the cylinder head 22 with gaskets (not
shown). The valve plate 58 have suction holes 60 and discharge
holes 62, where one suction hole and one discharge hole are
provided for each cylinder bore 30, thus, each compression chamber
33.
[0030] The valve plate 48 and the cylinder head 22 define a suction
chamber 64, a discharge chamber 66 and an intermediate pressure
chamber 68, and these chambers 64, 66, and 68 are independent from
one another. More specifically, the intermediate pressure chamber
68 is located in the center of the cylinder head 22, the discharge
chamber 66 annularly surrounds the intermediate pressure chamber
68, and the suction chamber 64 annularly surrounds the discharge
chamber 66. Thus, the intermediate pressure chamber 68, the
discharge chamber 66 and the suction chamber 64 form a triple
structure.
[0031] The suction chamber 64 communicates with the suction holes
60 of the respective compression chambers 33, and is connected to
the low-pressure section 2.sub.L of the circulation path 2 by the
aforementioned suction port 4s. The discharge chamber 66
communicates with the discharge holes 62 of the respective
compression chambers 33, and is connected to the high-pressure
section 2.sub.H of the circulation path 2 by the aforementioned
discharge port 4d. As clear from FIG. 2, the suction port 4s and
the discharge port 4d are formed in the cylinder head 22.
[0032] The suction holes 60 have suction valves 70, respectively.
The suction valves 70 can open and close the suction holes 60,
respectively. The discharge holes 62 have discharge valves 72,
respectively. The discharge valves 72 can open and close the
discharge holes 62, respectively. The suction valves 70 and the
discharge valves 72 are all reed valves. The suction valves 70 are
arranged on one end face of the valve plate 58 located on the
compression chamber side, and the discharge valves 72 are arranged
on the other end face of the valve plate 58. In FIG. 2, reference
character 73 denotes a valve retainer restricting the opening
action of the discharge valve 72.
[0033] The cylinder head 22 also has an introduction port 74. The
introduction port 74 communicates with the aforementioned
intermediate pressure chamber 68, and is connected to an
introduction path 76. As clear from FIG. 1, the introduction path
76 is connected to the aforementioned gas-liquid separator 10. The
introduction path 76 conveys an intermediate refrigerant in gas
phase from the gas-liquid separator 10 into the intermediate
pressure chamber 68 through the introduction port 74.
[0034] A rotary valve 78 is arranged between the intermediate
pressure chamber 68 and the main shaft 34. The rotary valve 78 is
cylindrical in shape and rotatably fitted into cylinder block 26.
Specifically, the cylinder block 26 has a cylinder hole 79 formed
to receive the rotary valve 78, and the rotary valve 78 is
air-tightly fitted within the cylinder hole 79.
[0035] The rotary valve 78 is coaxial with the main shaft 34 and
integrally connected to the main shaft 34. Specifically, the main
shaft 34 has a pin 80 projecting from its inner end into the rotary
valve 78, and the pin 80 is connected to the rotary valve 78 by a
key 82. Thus, the rotary valve 78 rotates integrally with the main
shaft 34. While the rotary valve 78 is rotating, the outer
cylindrical face of the rotary valve 78 is in an air-tight sliding
contact with the inner cylindrical face of the cylinder hole 79.
Further, the rotary valve 78 air-tightly penetrates through the
valve plate 58 into the intermediate pressure chamber 68, and is
rotatably fitted to the cylinder head 22 by means of an annular
thrust bearing 84.
[0036] A valve passage 86 is formed in the rotary valve 78. The
valve passage 86 has a valve opening 86a in the outer cylindrical
face of the rotary valve 78 and a communication opening 86b
communicating with the intermediate pressure chamber 86. As clear
from FIG. 2, the valve opening 86a is located near the
aforementioned one end face of the valve plate 58.
[0037] Further, a plurality of connection holes 88 are formed in
the cylinder block 26. The connection holes 88 are associated with
the compression chambers 33, respectively. More specifically, the
connection holes 88 are radial holes 88 extending from the inner
cylindrical face of the cylinder hole 79 to the respective
compression chambers 33, and each having an outer end open to their
associated compression chamber 33, near one end face of the valve
plate 58, and an inner end open at the inner cylindrical face of
the cylinder hole 79. The outer ends of the connection holes 88 are
always connected to their associated compression chambers 33,
irrespective of the reciprocating motion of the pistons 32. The
inner ends of the connection holes 88 are arranged circularly
around the rotary valve 78 at equal intervals, and while the rotary
valve 78 is rotating, become connected to the valve opening 86a of
the valve passage 86 periodically. Thus, the inner ends of the
connection holes 88 are located on the circular track which the
valve opening 86a describes while the rotary valve 78 is
rotating.
[0038] Thus, when the rotary valve 78 is rotated integrally with
the main shaft 34, the valve opening 86a of the valve passage 88
becomes connected to the connection holes 88 of the compression
chambers 33, successively. This means that while the rotary valve
78 is rotating, the intermediate pressure chamber 68 becomes
connected to the compression chambers 33 successively, by means of
the rotary valve 78. Thus, the rotary valve 78 serves as a
distribution valve for distributing the intermediate refrigerant in
the intermediate pressure chamber 68 to the compression chambers 33
by opening and closing the connection holes 88, successively. The
timing of distributing the intermediate refrigerant from the
intermediate pressure chamber 68 to each compression chamber 33 and
the duration of distribution will become clear from the description
given later.
[0039] As mentioned above, while the main shaft 34 is rotated, the
pistons 32 perform reciprocating motion within their own cylinder
bores 30, successively. Consequently, the refrigerant is sucked
into each compression chamber 33 from the suction chamber 64 via
the suction valve 70 and the suction hole 60. The sucked
refrigerant is then compressed within the compression chamber 33,
and the compressed refrigerant is discharged from the compression
chamber 33 into the discharge chamber 66 via the discharge hole 62
and the discharge valve 72. Since the discharge chamber 66 is
connected to the high-pressure section 2.sub.H of the circulation
path 2, the discharged refrigerant is supplied from the compressor
2 to the condenser 6. Since, on the other hand, the suction chamber
64 is connected to the low-pressure section 2.sub.L of the
circulation path 2, the refrigerant from the evaporator 14 is drawn
into each suction chamber 64 or each compression chamber 33.
[0040] The rotary valve 78 rotates integrally with the main shaft
34, and the valve opening 86a of the valve passage 86 of the rotary
valve 78 is connected to the connection hole 88 of the compression
chamber 33 which is in a process of compressing the refrigerant at
the distribution timing, only for the distribution duration. In
other words, the rotary valve 78 is opened at the distribution
timing, and closed when the distribution duration expires. The
distribution timing and distribution duration are set such that the
distribution to each compression chamber 33 is carried out while
the compression chamber is in the process of compressing the
refrigerant and terminates before the pressure of the compressed
refrigerant reaches to the pressure of the intermediate refrigerant
in the intermediate pressure chamber 68.
[0041] Thus, while the refrigerant is being compressed, the
intermediate refrigerant in the intermediate pressure chamber 68 is
injected into the compression chamber 33 through the rotary valve,
78 and the connection 88 when the rotary valve 78 is opened. As
mentioned above, the intermediate pressure chamber 68 is supplied
with the gaseous intermediate refrigerant from the aforementioned
gas-liquid separator 10 via the introduction path 76. Thus, the
intermediate refrigerant held in the intermediated pressure chamber
68 and injected into the compression chamber 33 has a temperature
sufficiently lower than the discharge temperature of the
refrigerant discharged from the compressor 4 and a pressure lower
than the discharge pressure of the refrigerant discharged from the
compressor 4. Since the low-temperature intermediate refrigerant
injected into the compression chamber 33 mixes with the
high-temperature refrigerant being compressed, the refrigerant
being compressed within the compression chamber 33 is cooled, which
restrains an increase in temperature of the refrigerant discharged
from the compressor 4.
[0042] Since the increase in temperature of the refrigerant
discharged is restricted in this manner, even when carbon dioxide
is used as the refrigerant, the thermal load on the compressor 4 is
reduced to a great extent, and even when a new alternative
refrigerant including a double bond hydrocarbons, such as R1234yf,
is used as the refrigerant, the double bond is not broken. Thus,
the compressor 4 according to the present invention allows use of
refrigerants suited to prevent global warming, such as carbon
dioxide and the aforementioned new alternative refrigerants.
[0043] Further, the above-described injection of the
low-temperature refrigerant into each compression chamber 33
increases the refrigerant compression efficiency in each
compression chamber 33, which results in a significant improvement
in energy efficiency of the refrigerator. This means easy
realization of a multi-effect cycle demanded for this type of
refrigerator.
[0044] The aforementioned crank chamber 24 is connected to the
suction chamber 64 and the discharge chamber 66 through connection
passages 96, 98 indicated in dashed line in FIG. 2, respectively.
These connection passages 96, 98 penetrate the valve plate 58 and
the cylinder block 26. The connection passage 96 includes an
orifice 100, and the connection passage 98 includes a
solenoid-operated control valve 102. The solenoid-operated control
valve 102 controls the amount of the high-pressure refrigerant
allowed to enter the crank chamber 24 from the discharge chamber
66, thereby regulating the pressure in the crank chamber 24.
[0045] The angle of inclination of the aforementioned swashplate 46
is determined by the compression reaction forces exerted on the
front face of the swashplate 56 by the respective pistons 32 and
the back pressure, i.e., the pressure in the crank chamber 24
exerted on the back face of the swashplate 46, and therefore varied
by regulating the pressure in the crank chamber 24. Since the angle
of inclination of the swashplate 46 determines the stroke of the
pistons 32, the amount of the refrigerant discharged from the
compressor 4 is varied according to the angle of inclination of the
swashplate 46.
[0046] Since the aforementioned connection holes 86 of the
compression chambers 33 are each located near the top dead center
of their associated piston 32, varying the stroke of the pistons
does not affect the timing and duration of distribution by the
rotary valve 78 to each compression chamber 33. Consequently, the
relationship between the pressure of the refrigerant discharged
from the compressor 4 and the pressure of the intermediate
refrigerant in the intermediate pressure chamber 68 is kept almost
constant, regardless of the varying stroke of the pistons 32, which
allows the low-temperature intermediate refrigerant to be stably
injected into each compression chamber 33 while the compression
chamber is in the process of compressing the refrigerant.
[0047] The present invention is not limited to the above-described
embodiment but can be modified in various ways.
[0048] For example, FIG. 3 shows a rotary valve 78 caused to rotate
independently from the main shaft 34. In this case, the rotary
valve 78 is connected to an output shaft 92 of an electric motor
90. The electric motor 90 is mounted on the outer face of the
cylinder head 22. Normally, the electric motor 90 causes the rotary
valve 78 to rotate in synchronization with the main shaft 34, but
can vary the timing and duration of distribution by the rotary
valve 78 as necessary.
[0049] FIG. 4 shows a solenoid-operated on-off valve 94
substituting for the rotary valve 78. The solenoid-operated on-off
valve 94 is provided for each compression chamber 33 and performs
the similar function as the above-described rotary valve 78.
[0050] The reciprocating compressor according to the present
invention may be configured as a fixed displacement compressor, and
may be driven by an electric motor in place of the engine. Further,
the reciprocating motion mechanism is not limited to the
illustrated swashplate type but may be a single sided piston or
both sided piston swashplate type, or another axial piston
type.
* * * * *