FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
ROTARY COMPRESSOR;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION
AND THE MANNER IN WHICH IT IS TO BE PERFORMED

2
DESCRIPTION
Technical Field
[0001]
5 The present disclosure relates to a rotary compressor that includes an injection
mechanism.
Background Art
[0002]
A conventional rotary compressor has a configuration where a compression
10 mechanism unit and an electric motor unit are disposed in a sealed container, the
electric motor unit driving the compression mechanism unit via a rotary shaft. The
compression mechanism unit mainly includes a cylinder, a rotary piston, and a vane,
the cylinder having a cylindrical shape, the rotary piston being rotatably mounted on
an eccentric shaft portion of the rotary shaft, the vane being slidably disposed in a
15 vane groove formed on the cylinder. A through hole is formed in the cylinder
substantially at the center to extend in the axial direction. The through hole is closed
by end plates disposed on both end surfaces of the cylinder in the axial direction, so
that a cylinder chamber is formed in the cylinder. A compression chamber is formed
in the cylinder chamber, and is formed by the vane that provides a partition. When
20 the rotary shaft rotates, thus causing the rotary piston to perform eccentric rotation in
the cylinder chamber, the volume of the compression chamber reduces, so that
refrigerant is compressed.
[0003]
For such a rotary compressor, there is a known configuration where an injection
25 port is formed in the end plate to inject refrigerant at intermediate pressure into the
compression chamber of the compression mechanism unit (see Patent Literature 1,
for example). The position of the injection port is set such that the injection port
faces the inside of the compression chamber in a state where the pressure in the
compression chamber is low, but the injection port is located inward of the outer
30 peripheral surface of a rotating rotary piston to prevent the injection port from facing

3
the compression chamber in a state where the pressure in the compression chamber
is high.
[0004]
In the case where the diameter of the injection port is increased to increase an
5 injection amount, there may be a case where the injection port is located inward of
the inner peripheral surface of the rotary piston in the process where the rotary piston
performs eccentric rotation. A space portion where refrigerating machine oil is
collected is provided at a position inward of the inner peripheral surface of the rotary
piston. Therefore, when the injection port is located inward of the inner peripheral
10 surface of the rotary piston and faces the space portion, problems occur, such as
back flow of injection refrigerant and discharge of refrigerating machine oil.
[0005]
In view of the above, in Patent Literature 1, an annular sealing portion
protruding inward in the radial direction is integrally provided to the surface of the
15 rotary piston that is in contact with the end plate. Such a sealing portion closes the
portion of the injection port that is located inward of the inner peripheral surface of the
rotary piston even when the rotary piston is at any rotational phase position, thus
preventing the injection port from facing the space portion formed at the position
inward of the inner peripheral surface of the rotary piston.
20 Citation List
Patent Literature
[0006]
Patent Literature 1: Japanese Unexamined Patent Application Publication No.
11-013664
25 Summary of Invention
Technical Problem
[0007]
For the rotary compressors, there is a demand for a small-sized compression
mechanism unit having a large displacement volume. To increase the displacement
30 volume while the size of the rotary compressor is maintained, it is effective to increase

4
the eccentricity of the eccentric shaft portion of the rotary shaft while the inner
diameter of the cylinder of the compression mechanism unit and the diameter of the
main shaft portion of the rotary shaft are maintained. The eccentricity of the
eccentric shaft portion of the rotary shaft can be increased to a maximum by causing
5 the end of the main shaft portion in the radial direction and the end of the eccentric
shaft portion in the radial direction to be coplanar with each other.
[0008]
In Patent Literature 1, it is possible to avoid a situation where the injection port
faces the above-mentioned space portion by providing the annular sealing portion to
10 the rotary piston. However, Patent Literature 1 has the following problem. That is,
due to the provision of the sealing portion, a gap of at least an amount corresponding
to the thickness of the sealing portion in the radial direction is formed between the
rotary piston and the main shaft portion of the rotary shaft that is caused to pass
through a position inward of the sealing portion, so that there is a problem that
15 eccentricity cannot be increased to a maximum and there are restrictions on
eccentricity.
[0009]
The present disclosure has been made in view of such a point, and it is an
object of the present disclosure to provide a rotary compressor having a structure that
20 can prevent the injection port from facing the inner side of the rotary piston and
allowing the eccentricity of the eccentric shaft portion of the rotary shaft to be
increased to a maximum.
Solution to Problem
[0010]
25 A rotary compressor according to an embodiment of the present disclosure is a
rotary compressor including a compression mechanism unit configured to compress
refrigerant in a compression chamber, wherein refrigerant at an intermediate pressure
is injected into the compression chamber of the compression mechanism unit from an
injection port, wherein the compression mechanism unit includes: a rotary shaft
30 including a main shaft portion and an eccentric shaft portion; a cylinder having a

5
cylinder chamber; a rotary piston mounted on the eccentric shaft portion of the rotary
shaft and configured to perform eccentric rotation in the cylinder chamber; two end
plates disposed on both end surfaces of the cylinder in an axial direction of the rotary
shaft; a vane protruding into the cylinder chamber of the cylinder, and configured to
5 be brought into contact with the rotary piston to form the compression chamber in the
cylinder chamber; and a seal plate configured to move in conjunction with the
eccentric rotation of the rotary piston, and configured to close a portion of the injection
port that is located inward of an inner peripheral surface of the rotary piston, the
injection port being formed in one end plate of the two end plates, and the seal plate
10 is separated from the rotary piston, is rotatable relative to the rotary piston, and has a
through hole through which the main shaft portion of the rotary shaft is caused to
pass, the through hole being open outward in a radial direction.
Advantageous Effects of Invention
[0011]
15 The rotary compressor of the embodiment of the present disclosure includes
the seal plate configured to close a portion of the injection port that is located inward
of the inner peripheral surface of the rotary piston, thus having a structure that can
prevent the injection port from facing the inner side of the rotary piston. The seal
plate is separated from the rotary piston, is rotatable relative to the rotary piston, and
20 has the through hole through which the main shaft portion of the rotary shaft is
caused to pass, the through hole being open outward in the radial direction. The
through hole is open outward in the radial direction as described above and hence,
the main shaft portion of the rotary shaft can be disposed at a position close to the
open side of the through hole whereby it is possible to adjust the eccentricity of the
25 eccentric shaft portion according to the position of the main shaft portion of the rotary
shaft in the through hole. Accordingly, in the case where the main shaft portion is
moved to the open side of the through hole until the main shaft portion is brought into
contact with the inner peripheral surface of the rotary piston, it is possible to increase
the eccentricity of the eccentric shaft portion of the rotary shaft to a maximum.
30 Brief Description of Drawings

6
[0012]
[Fig. 1] Fig. 1 is a schematic cross-sectional view of a rotary compressor
according to Embodiment.
[Fig. 2] Fig. 2 is a schematic cross-sectional view of a compression mechanism
5 unit taken along line A-A in Fig. 1.
[Fig. 3] Fig. 3 is a diagram showing a seal plate of the rotary compressor
according to Embodiment.
[Fig. 4] Fig. 4 is a diagram for describing a portion where the seal plate shown
in Fig. 3 is disposed.
10 [Fig. 5] Fig. 5 is a diagram showing a state where the seal plate shown in Fig. 3
is disposed in a rotary piston shown in Fig. 4.
[Fig. 6] Fig. 6 is a diagram showing a compression operation of the rotary
compressor according to Embodiment, and is also a schematic cross-sectional view
of the compression mechanism unit taken along line A-A in Fig. 1.
15 [Fig. 7] Fig. 7 is a diagram for describing a region where an injection port can
be disposed in the rotary compressor according to Embodiment.
[Fig. 8] Fig. 8 is a diagram for describing the eccentricity of an eccentric shaft
portion of a conventional structure.
[Fig. 9] Fig. 9 is a partially enlarged view of Fig. 8.
20 [Fig. 10] Fig. 10 is a diagram for describing the eccentricity of an eccentric shaft
portion of the rotary compressor according to Embodiment.
[Fig. 11] Fig. 11 is a partially enlarged view of Fig. 10.
[Fig. 12] Fig. 12 is a diagram for describing a step for assembling a twin rotary
compressor having a conventional structure.
25 [Fig. 13] Fig. 13 is a diagram for describing the step for assembling the twin
rotary compressor having the conventional structure.
[Fig. 14] Fig. 14 is a diagram for describing a step for assembling the rotary
compressor according to Embodiment.
[Fig. 15] Fig. 15 is a diagram showing a modification 1 of the rotary compressor
30 according to Embodiment.

7
[Fig. 16] Fig. 16 is a diagram showing a modification 2 of the rotary compressor
according to Embodiment.
[Fig. 17] Fig. 17 is a diagram showing a modification 3 of the rotary compressor
according to Embodiment.
5 Description of Embodiments
[0013]
Embodiment
Fig. 1 is a schematic cross-sectional view of a rotary compressor according to
Embodiment. Fig. 2 is a schematic cross-sectional view of a compression
10 mechanism unit taken along line A-A in Fig. 1.
The rotary compressor shown in Fig. 1 is a rotary compressor with an injection
mechanism. The rotary compressor has a configuration where a compression
mechanism unit 2, an electric motor unit 3, and a rotary shaft 4 are disposed in a
sealed container 1, the rotary shaft 4 transmitting a driving force of the electric motor
15 unit 3 to the compression mechanism unit 2. In Embodiment, the description will be
made by taking, as an example, a twin-rotary rotary compressor where the
compression mechanism unit 2 includes two cylinders. However, the configuration is
not limited to the above, and the rotary compressor may include one or three or more
cylinders. In the description made hereinafter, the longitudinal direction (the vertical
20 direction in the drawing) of the sealed container 1, that is, a direction in which the
rotary shaft 4 extends is referred to as "axial direction", a direction perpendicular to
the axial direction is referred to as "radial direction", and a direction about the rotary
shaft 4 is referred to as "circumferential direction".
[0014]
25 In the rotary compressor, the rotary shaft 4 is rotated by the electric motor unit
3, thus driving the compression mechanism unit 2 to compress refrigerant.
Refrigerant is suctioned into the sealed container 1 through a suction muffler 8, and is
compressed by the compression mechanism unit 2 and, thereafter, becomes a hightemperature high-pressure gas, and is discharged into the sealed container 1. The
30 refrigerant gas discharged into the sealed container 1 passes through a gap in the

8
electric motor unit 3, and is then discharged into a refrigerant circuit from a discharge
pipe 5.
[0015]
The lower portion of the sealed container 1 forms an oil reservoir where
5 refrigerating machine oil is collected. The refrigerating machine oil in the oil
reservoir is suctioned through a hollow hole in the manner of a centrifugal pump that
makes use of the rotation of the rotary shaft 4, the hollow hole being provided in the
rotary shaft 4 to extend in the axial direction. The suctioned refrigerating machine oil
is supplied to respective sliding portions through oil supply holes extending from the
10 hollow hole to an outer peripheral portion. With such a configuration, gaps formed
between constitutional components are sealed by the refrigerating machine oil and
hence, it is possible to prevent damage caused by direct contact between the rotary
shaft 4 or a rotary piston 22, which will be described later, and each constitutional
component that comes into contact with the rotary shaft 4 or the rotary piston 22,
15 which are sliding components. Sealing brought about by the refrigerating machine
oil also acts to prevent leakage of refrigerant.
[0016]
The rotary shaft 4 includes a main shaft portion 4a and eccentric shaft portions
4b that are eccentric to the shaft center of the main shaft portion 4a. Two eccentric
20 shaft portions 4b are provided, the number of eccentric shaft portions 4b being equal
to the number of cylinders. An oil separator 6 is fitted on the upper portion of the
rotary shaft 4, and separates refrigerant and refrigerating machine oil from each other.
The oil separator 6 is formed to have a disk shape, and is installed at a position where
the oil separator 6 collides with mixed fluid of refrigerating machine oil and refrigerant
25 flowing toward the discharge pipe 5 from the compression mechanism unit 2. Due to
the collision of the mixed fluid with the oil separator 6, the mixed fluid is separated into
refrigerant and refrigerating machine oil. By separating the mixed fluid into
refrigerant and refrigerating machine oil with the oil separator 6, it is possible to
prevent refrigerating machine oil from being discharged to the outside of the
30 compressor through the discharge pipe 5 together with refrigerant discharged from

9
the compression mechanism unit 2. As a result, it is possible to prevent seizure of
the sliding portions caused by depletion of oil in the sealed container 1.
[0017]
The electric motor unit 3 includes a stator 3a and a rotor 3b. The rotary shaft
5 4 is fixed to the rotor 3b. The rotation of the rotor 3b causes the rotary shaft 4 to
rotate, so that rotational power is transmitted to the compression mechanism unit 2.
[0018]
The compression mechanism unit 2 includes a first compression unit 20A, a
second compression unit 20B, an upper bearing 10 disposed on the upper end
10 surface of the first compression unit 20A, a lower bearing 11 disposed on the lower
end surface of the second compression unit 20B, and an intermediate plate 12. The
end portion of an injection pipe 7 is connected to the intermediate plate 12, the
injection pipe 7 penetrating through the sealed container 1 from the outside.
Hereinafter, the first compression unit 20A and the second compression unit 20B may
15 be collectively referred to as "compression unit 20" when it is unnecessary to
differentiate the first compression unit 20A and the second compression unit 20B from
each other.
[0019]
The upper bearing 10 includes a hollow cylindrical bearing portion 10a and an
20 annular plate-like end plate 10b, the bearing portion 10a rotatably supporting the
rotary shaft 4, the end plate 10b closing the upper end surface of a cylinder 21, which
will be described later. In the same manner, the lower bearing 11 includes a hollow
cylindrical bearing portion 11a and an annular plate-like end plate 11b, the bearing
portion 11a rotatably supporting the rotary shaft 4, the end plate 11b closing the lower
25 end surface of a cylinder 21, which will be described later.
[0020]
The end plate 10b of the upper bearing 10 and the end plate 10b of the lower
bearing 11 have discharge ports (not shown in the drawing). An upper discharge
muffler 13 and a lower discharge muffler 14 are installed to cover such discharge
30 ports. The upper discharge muffler 13 and the lower discharge muffler 14 are

10
provided to reduce noise amplified due to resonance in a space in the sealed
container 1.
[0021]
Next, the configurations of the first compression unit 20A and the second
5 compression unit 20B of the compression mechanism unit 2 will be described. The
first compression unit 20A and the second compression unit 20B basically have
substantially the same configuration and hence, the first compression unit 20A will be
described hereinafter as a representative example.
[0022]
10 The first compression unit 20A includes the cylindrical cylinder 21, the rotary
piston 22, and a vane 23, the cylinder 21 having a through hole penetrating through
the cylinder 21 in the axial direction (the vertical direction in Fig. 1), the rotary piston
22 being rotatably mounted on the eccentric shaft portion 4b of the rotary shaft 4 and
eccentrically rotating in a cylinder chamber. The first compression unit 20A further
15 includes a seal plate 40, which is separated from the rotary piston 22. The upper
bearing 10 and the intermediate plate 12 are respectively disposed on both end
surfaces of the cylinder 21 in the axial direction. The through hole of the cylinder 21
is closed by the end plate 10b of the upper bearing 10 and the intermediate plate 12,
so that a cylinder chamber 24 is formed in the cylinder 21. As described above, the
20 end plate 10b of the upper bearing 10 and the intermediate plate 12 serve as end
plates that close the through hole.
[0023]
As shown in Fig. 2, a vane groove 23a extending in the radial direction is
formed on the cylinder 21, and the vane 23 is disposed in the vane groove 23a such
25 that the vane 23 is slidable in the radial direction. The vane 23 protrudes into the
cylinder chamber 24, and the distal end portion of the vane 23 is brought into contact
with the rotary piston 22, thus partitioning the inside of the cylinder chamber 24 into a
suction chamber 24a and a compression chamber 24b.
[0024]
30 An inner peripheral surface 22c of the cylinder 21 has a suction port 26 that

11
communicates with the suction chamber 24a, and refrigerant from the suction muffler
8 is introduced into the suction chamber 24a through the suction port 26. The inner
peripheral surface 22c of the cylinder 21 also has a discharge port 27 that
communicates with the compression chamber 24b, and refrigerant that is compressed
5 to a discharge pressure in the compression chamber 24b is discharged from the
discharge port 27.
[0025]
As shown in Fig. 1, the compression mechanism unit 2 further includes an
injection flow passage 30 that introduces liquid refrigerant at intermediate pressure or
10 injection refrigerant being gas refrigerant to the compression chamber 24b. The
injection flow passage 30 is formed in the intermediate plate 12. The injection flow
passage 30 is specifically a flow passage through which injection refrigerant is
introduced into the compression chamber 24b of the first compression unit 20A and
into the compression chamber 24b of the second compression unit 20B. Injection
15 ports 30a, which are the downstream ends of the injection flow passage 30, are open
on the upper and lower end surfaces of the intermediate plate 12. Injection
refrigerant that flows into the injection flow passage 30 from the outside is introduced
into the compression chamber 24b of the first compression unit 20A and into the
compression chamber 24b of the second compression unit 20B from the respective
20 injection ports 30a. Space portions 50 are provided at step portions between the
main shaft portion 4a and the eccentric shaft portions 4b on the inner peripheral side
of the rotary piston 22, refrigerating machine oil and refrigerant being collected in the
space portions 50.
[0026]
25 Next, the operation of the rotary compressor will be described.
When power is supplied to the electric motor unit 3, the rotary shaft 4 fixed to
the rotor 3b rotates, and refrigerant is suctioned into the suction chamber 24a in the
cylinder 21 from the suction port 26 through the suction muffler 8 from the refrigerant
circuit. The refrigerant suctioned into the suction chamber 24a is compressed by the
30 eccentric rotational motion of the rotary piston 22. The refrigerant that is

12
compressed, therefore having a high pressure, is released from the compression
chamber 24b into the sealed container 1 through the discharge port 27 and through a
discharge port (not shown in the drawing) formed in the upper bearing 10. The
refrigerant gas released into the sealed container 1 passes through the discharge
5 pipe 5, and is discharged into the refrigerant circuit disposed outside the compressor.
[0027]
Injection refrigerant that flows into the injection pipe 7 from the refrigerant
circuit disposed outside the compressor is injected into the cylinder chamber 24 from
the injection port 30a through the injection flow passage 30. Injection refrigerant is
10 injected into the cylinder chamber 24 when the injection port 30a faces the cylinder
chamber 24. During the period in which the rotary piston 22 rotates through one
revolution, injection refrigerant is injected into the cylinder chamber 24 within a range
of a specific rotational phase that corresponds to the position of the injection port 30a.
[0028]
15 A conventional rotary compressor adopts the following structure as a structure
that prevents an injection port from facing a space portion formed on the inner side of
the inner peripheral surface of a rotary piston when the diameter of the injection port
is increased to increase an injection amount. That is, an annular sealing portion
protruding inward in the radial direction is integrally provided to the surface of the
20 rotary piston that is in contact with the injection port. Although the description will be
made hereinafter with reference to drawings, this structure has restrictions on the
eccentricity of an eccentric shaft portion and hence, eccentricity cannot be increased
to a maximum.
[0029]
25 In view of the above, in Embodiment, by using the seal plate 40, the injection
port 30a is prevented from facing the space portion 50 (see Fig. 1) formed on the
inner side of the inner peripheral surface 22c of the rotary piston 22, and the
eccentricity of the eccentric shaft portion 4b can be increased to a maximum.
Hereinafter, first, the configuration and the manner of operation of the seal plate 40
30 will be described and, thereafter, a point that the eccentricity of the eccentric shaft

13
portion 4b can be increased to a maximum will be described.
[0030]
Fig. 3 is a diagram showing the seal plate of the rotary compressor according
to Embodiment. Fig. 3(a) is a plan view, and Fig. 3(b) is a cross-sectional view.
5 Fig. 4 is a diagram for describing a portion where the seal plate shown in Fig. 3 is
disposed, and is also a diagram showing the rotary piston of the first compression
unit. Fig. 4(a) is a plan view, and Fig. 4(b) is a cross-sectional view. Fig. 5 is a
diagram showing a state where the seal plate shown in Fig. 3 is disposed in the rotary
piston shown in Fig. 4. Fig. 5(a) is a plan view, and Fig. 5(b) is a cross-sectional
10 view. In Fig. 5(a), a seal plate portion is hatched to clearly show the position of the
seal plate portion.
[0031]
As shown in Fig. 3, the seal plate 40 has a shape having a circular outer shape
and a through hole 41 through which the main shaft portion 4a of the rotary shaft 4 is
15 caused to pass, the through hole 41 being open outward in the radial direction. In
other words, the seal plate 40 has a shape where a portion of an annular part is
notched. As shown in Fig. 4, an annular recessed portion 22b that is coaxial with the
rotary piston 22 is formed on an end surface 22a out of both end surfaces of the
rotary piston 22 in the axial direction, the end surface 22a being disposed close to the
20 injection port 30a. The seal plate 40 is rotatably disposed in the recessed portion
22b.
[0032]
The seal plate 40 is brought into contact with the intermediate plate 12 in a
state of being disposed in the recessed portion 22b. The seal plate 40 has a portion
25 protruding inward from the inner peripheral surface 22c of the rotary piston 22, and
this protruding portion closes a portion of the injection port 30a that is located inward
of the inner peripheral surface 22c of the rotary piston 22.
[0033]
As shown in Fig. 5, the main shaft portion 4a of the rotary shaft 4 passes
30 through the through hole 41 at a position closer to the open side of the through hole

14
41 of the seal plate 40 than a center axis O of the rotary piston 22.
[0034]
It is described that the seal plate 40 is rotatably disposed in the recessed
portion 22b. However, the seal plate 40 does not rotate through one revolution in the
5 recessed portion 22b. Straight inner surfaces 41a of the through hole 41 on the
open side are brought into contact with the outer peripheral surface of the main shaft
portion 4a when the seal plate 40 rotates in the recessed portion 22b, so that the
rotation range of the seal plate 40 is adjusted. The rotation range is adjusted to
adjust the posture of the seal plate 40 at the time of the rotary piston 22 performing
10 the eccentric rotation. This point will be described with reference to following Fig. 6.
[0035]
Next, the manner of operation of the seal plate 40 having the above-mentioned
configuration will be described. Fig. 6 is a diagram showing the compression
operation of the rotary compressor according to Embodiment, and is also a schematic
15 cross-sectional view of the compression mechanism unit taken along line A-A in Fig.
1.
First, the motion of the rotary piston 22 will be described. Fig. 6 shows the
states where the rotational phase of the rotary shaft 4 advances to 0°, 90°, 180°, and
270°, thus causing the rotary piston 22 to perform an eccentric rotational motion while
20 being in contact with the inner peripheral surface of the cylinder 21.
[0036]
The seal plate 40 also performs an eccentric rotational motion in conjunction
with the eccentric rotational motion of the rotary piston 22. Although the seal plate
40 is rotatable relative to the rotary piston 22, the rotation range of the seal plate 40 is
25 adjusted. Therefore, the seal plate 40 moves in conjunction with the eccentric
rotation of the rotary piston 22 while maintaining the posture where the open side of
the through hole 41 faces in a direction opposite to the eccentric direction of the
eccentric shaft portion 4b (not shown in Fig. 6. See Fig. 5 and other drawings).
Specifically, when the rotational phase is 0°, the seal plate 40 has a posture where
30 the open side of the through hole 41 faces in the downward direction on the surface

15
of the paper on which Fig. 6 is shown, in other words, the seal plate 40 has a posture
where the open side of the through hole 41 faces in a direction opposite to the
eccentric direction (the upward direction on the surface of the paper on which Fig. 6 is
shown) of the eccentric shaft portion 4b. When the rotational phase is 90°, the seal
5 plate 40 has a posture obtained by rotating the seal plate 40 in the counterclockwise
direction by 90° from the posture when the rotational phase is 0°. In the same
manner, for each rotational phase advance to 180° and 270°, the posture of the seal
plate 40 also changes to a posture obtained by rotating the seal plate 40 in the
counterclockwise direction by 90°.
10 [0037]
When the rotational phase is 0°, the injection port 30a faces the suction
chamber 24a that is formed immediately after the completion of the suction. When
the rotational phase is 90°, the injection port 30a faces the compression chamber
24b, and a portion of the injection port 30a is closed by the rotary piston 22. When
15 the rotational phase is 180°, the injection port 30a faces the inner side of the inner
peripheral surface 22c of the rotary piston 22. However, the injection port 30a is
closed by the seal plate 40. That is, even in a state where the injection port 30a is
located inward of the inner peripheral surface 22c of the rotary piston 22, it is possible
to close the injection port 30a with the seal plate 40. When the rotational phase is
20 270°, the injection port 30a is closed by the rotary piston 22 per se.
[0038]
The seal plate 40 is provided as described above and hence, even in a state
where the injection port 30a is located inward of the inner peripheral surface 22c of
the rotary piston 22, it is possible to close the injection port 30a with the seal plate 40.
25 Accordingly, injection refrigerant does not flow into the cylinder chamber 24 at the
time of performing injection and hence, it is possible to suppress lowering of
performance caused by inflow of injection refrigerant into the space portion 50 (see
Fig. 1). At the same time, it is also possible to suppress the deterioration of reliability
that is caused by lowering of lubricating ability brought about when injection
30 refrigerant blows out refrigerating machine oil stored in the space portion 50. Also in

16
the case where injection is not performed, it is possible to suppress a situation where
refrigerating machine oil stored in the space portion 50 flows out to the injection flow
passage 30 through the injection port 30a and hence, the deterioration of reliability
can be suppressed.
5 [0039]
Further, due to the provision of the seal plate 40, it is possible to avoid
communication between the injection port 30a and the inner side of the inner
peripheral surface 22c of the rotary piston 22 irrespective of the size of the injection
port 30a. Therefore, it is possible to increase the diameter of the injection port 30a,
10 thus increasing an injection amount.
[0040]
In determining a position where the injection port 30a is disposed, it is
unnecessary to narrow down the position of the injection port 30a to a position where
such communication can be avoided and hence, it is possible to increase the degree
15 of freedom in design of the position where the injection port 30a is disposed. The
description will be made with reference to following Fig. 7 for a point that it is possible
to increase the degree of freedom in design of the position where the injection port
30a is disposed.
[0041]
20 Fig. 7 is a diagram for describing a region where the injection port can be
disposed in the rotary compressor according to Embodiment.
An annular region 60 that is hatched in Fig. 7 is a region where the injection
port 30a faces a position inward of the inner peripheral surface 22c of the rotary
piston 22 during the period in which the rotary piston 22 performs an eccentric
25 rotational motion. Accordingly, in the case of a structure where the seal plate 40 is
not provided, it is necessary to dispose the injection port 30a at a position avoiding
the annular region 60. Specifically, it is necessary to dispose the injection port 30a in
a region outside the outer periphery of the annular region 60. A region inside the
inner periphery of the annular region 60 is a region that is closed by the rotary piston
30 22 at all rotational phases, thus being a region where the injection port 30a cannot be

17
disposed.
[0042]
In contrast, in Embodiment, the seal plate 40 is provided and hence, even
when the injection port 30a is located in the annular region 60, it is possible to close
5 the injection port 30a with the seal plate 40. Therefore, the annular region 60 is also
included in a region where the injection port 30a can be disposed and hence, it is
possible to increase the degree of freedom in design of the position where the
injection port 30a is disposed.
[0043]
10 Next, by comparing the conventional structure with Embodiment, the
description will be made for a point that the eccentricity of the eccentric shaft portion
4b can be increased to a maximum due to the provision of the seal plate 40.
[0044]
Fig. 8 is a diagram for describing the eccentricity of an eccentric shaft portion of
15 a conventional structure. Fig. 8 shows an example where the conventional structure
is applied to a rotary compressor including two cylinders. Fig. 9 is a partially
enlarged view of Fig. 8. Fig. 10 is a diagram for describing the eccentricity of the
eccentric shaft portion of the rotary compressor according to Embodiment. Fig. 11 is
a partially enlarged view of Fig. 10.
20 [0045]
First, the conventional structure will be described as a comparison example.
As shown in Fig. 8 and Fig. 9, in the conventional structure, an annular sealing
portion 140 protruding inward in the radial direction is integrally provided to the end
portion of a rotary piston 122 on the injection port 130a side. The sealing portion
25 140 extends in the circumferential direction without a notch, thus having an annular
shape. As shown in Fig. 9, the sealing portion 140 has a thickness w in the radial
direction over the entire portion in the circumferential direction. A rotary shaft 104
passes through a position inward of the annular sealing portion 140 and hence, a gap
of at least an amount corresponding to the thickness w of the sealing portion is
30 formed between an outer peripheral surface 104aa of a main shaft portion 104a and

18
an inner peripheral surface 122a of the rotary piston 122, and an eccentric shaft
portion 104b is disposed to fit in this gap. Accordingly, it is necessary to ensure the
position of the eccentric shaft portion 104b for the amount corresponding to the
thickness w of the sealing portion 140 in the radial direction on a side (the right side in
5 Fig. 9) opposite to the eccentric side (the left side in Fig. 9) of the eccentric shaft
portion 104b. Therefore, on the eccentric side of the eccentric shaft portion 104b, a
distance between the inner peripheral surface 122a of the rotary piston 122 and the
outer peripheral surface 104aa of the main shaft portion 104a is α.
[0046]
10 In contrast, in the structure of Embodiment, the through hole 41 of the seal
plate 40 is open outward in the radial direction, the main shaft portion 4a of the rotary
shaft 4 being caused to pass through the through hole 41. Therefore, the main shaft
portion 4a of the rotary shaft 4 can be disposed by moving the main shaft portion 4a
toward the open side of the through hole 41, that is, to a position where the main
15 shaft portion 4a comes into contact with the inner peripheral surface 22c of the rotary
piston 22. Therefore, unlike the conventional structure, it is unnecessary to ensure a
portion of the eccentric shaft portion for an amount corresponding to w on the side
opposite to the eccentric side. Accordingly, as shown in Fig. 10 and Fig. 11, it is
possible to obtain a state where an outer peripheral surface 4aa of the main shaft
20 portion 4a is brought into contact with the inner peripheral surface 22c of the rotary
piston 22 by causing the end of the main shaft portion 4a in the radial direction and
the end of the eccentric shaft portion 4b in the radial direction to be coplanar with
each other.
[0047]
25 With such a configuration, in the structure of Embodiment, a distance β
between the inner peripheral surface 22c of the rotary piston 22 and the outer
peripheral surface 4aa of the main shaft portion 4a can be set to be larger than the
distance α in the conventional structure on the eccentric side (the left side in Fig. 11)
of the eccentric shaft portion 4b and hence, it is possible to achieve a configuration
30 that can increase the eccentricity of the eccentric shaft portion 4b to a maximum.

19
Fig. 10 and Fig. 11 show the configuration where the eccentricity of the eccentric shaft
portion 4b is increased to a maximum. However, it is suitably determined whether
the eccentricity of the eccentric shaft portion 4b is increased to a maximum. In short,
with the structure of Embodiment, the main shaft portion 4a of the rotary shaft 4 can
5 be disposed at a position close to the open side of the through hole 41 and hence, it
is possible to adjust the eccentricity of the eccentric shaft portion 4b up to a maximum
by changing the position of the main shaft portion 4a of the rotary shaft 4 in the
through hole 41.
[0048]
10 The eccentricity of the eccentric shaft portion 4b is defined as an amount of
displacement of the eccentric shaft portion 4b from the position coaxial with the main
shaft portion 4a. In such a case, the maximum eccentricity in the structure of
Embodiment corresponds to the difference between the radius of the main shaft
portion 4a and the radius of the eccentric shaft portion 4b. Accordingly, with the
15 structure of Embodiment, the eccentric shaft portion 4b of the rotary shaft 4 can be
eccentric from the position coaxial with the main shaft portion 4a in a direction
opposite to the open side of the through hole 41 within a range of equal to or less
than the difference between the radius of the main shaft portion 4a and the radius of
the eccentric shaft portion 4b.
20 [0049]
Next, ease of assembly will be described. The seal plate 40 of Embodiment
has the through hole 41 that is open outward in the radial direction. Therefore, the
seal plate 40 does not have a closed annular shape, but has an annular shape having
a notched portion. By causing the seal plate 40 to have an annular shape having the
25 notched portion as described above, it is also possible to obtain an advantageous
effect of increasing ease of assembly compared with a case where a closed annular
shape is adopted. Hereinafter, the description will be made by comparing the
conventional structure with Embodiment.
[0050]
30 Fig. 12 is a diagram for describing a step for assembling a twin rotary

20
compressor having a conventional structure, and is also a diagram showing a state
before rotary pistons are installed. Fig. 13 is a diagram for describing the step for
assembling the twin rotary compressor having the conventional structure, and is also
a diagram showing a state after the rotary pistons are installed. Fig. 14 is a diagram
5 for describing a step for assembling the rotary compressor according to Embodiment.
In Fig. 12 to Fig. 14, the illustration of the intermediate plate is omitted. The
intermediate plate has an inner diameter larger than the outer diameter of the
eccentric shaft portion and hence, it is sufficient to install the intermediate plate by
allowing the eccentric shaft portion to pass through a position inward of the
10 intermediate plate. It is sufficient to install the intermediate plate at any time before
the rotary pistons are installed on the eccentric shaft portion.
[0051]
In the case of a twin rotary compressor including two cylinders and having a
structure where both injection ports for compression chambers of the two cylinders
15 are provided in the intermediate plate, it is impossible to actually assemble the
conventional structure. That is, in assembling the conventional structure, as shown
in Fig. 12, the respective rotary pistons 122 are installed on the rotary shaft 104 from
both end sides, the rotary shaft 104 having two eccentric shaft portions 104b. An
inner diameter w1 of the sealing portion 140 is smaller than an outer diameter w2 of
20 the eccentric shaft portion 104b. Therefore, as shown in Fig. 13, each sealing
portion 140 cannot pass through each eccentric shaft portion 104b and hence, each
rotary piston 22 cannot be installed on the outer periphery of each eccentric shaft
portion 4b.
[0052]
25 In contrast, in the structure of Embodiment, each seal plate 40 has the through
hole 41 and has an annular shape having a notched portion, thus obtaining a high
degree of freedom in installation and hence, the structure of Embodiment can be
assembled. That is, as shown in Fig. 14, each seal plate 40 can be installed on the
rotary shaft 4 including the two eccentric shaft portions 4b, that is, can be installed in
30 the recessed portion 22b of each rotary piston 22 from the lateral side of the rotary

21
shaft 4 by making use of the through hole 41 of the seal plate 40. Accordingly, the
structure of Embodiment can be easily assembled.
[0053]
The configuration has been described above where both of the two injection
5 ports 30a are formed in the intermediate plate 12. However, the configuration is not
limited to such a configuration. Other constitutional examples will be described with
reference to following Fig. 15 to Fig. 17.
[0054]
Fig. 15 is a diagram showing a modification 1 of the rotary compressor
10 according to Embodiment. Fig. 16 is a diagram showing a modification 2 of the
rotary compressor according to Embodiment. Fig. 17 is a diagram showing a
modification 3 of the rotary compressor according to Embodiment.
As shown in Fig. 15, a configuration may be adopted where the injection port
30a for the first compression unit 20A is formed in the end plate 10b of the upper
15 bearing 10, and the injection port 30a for the second compression unit 20B is formed
in the end plate 11b of the lower bearing 11. As shown in Fig. 16, a configuration
may be adopted where the injection port 30a for the first compression unit 20A is
formed in the end plate 10b of the upper bearing 10, and the injection port 30a for the
second compression unit 20B is formed in the intermediate plate 12. Further, as
20 shown in Fig. 17, a configuration may be adopted where the injection port 30a for the
first compression unit 20A is formed in the intermediate plate 12, and the injection
port 30a for the second compression unit 20B is formed in the end plate 11b of the
lower bearing 11.
[0055]
25 In short, the configuration may be adopted where both of the two injection ports
30a are formed in the intermediate plate 12, the configuration may be adopted where
the two injection ports 30a are respectively formed in the end plate 10b and the end
plate 10b, or the configuration may be adopted where one of the two injection ports
30a is formed in one of the end plate 10b and the end plate 10b, and the other of the
30 two injection ports 30a is formed in the intermediate plate 12.

22
[0056]
As described above, the rotary compressor of Embodiment is a rotary
compressor including the compression mechanism unit 2 configured to compress
refrigerant in the compression chamber 24b, refrigerant at intermediate pressure
5 being injected into the compression chamber 24b of the compression mechanism unit
2 from the injection port 30a. The compression mechanism unit 2 includes the rotary
shaft 4 including the main shaft portion 4a and the eccentric shaft portion 4b, the
cylinder 21 having the cylinder 21 chamber, and the rotary piston 22 mounted on the
eccentric shaft portion 4b of the rotary shaft 4 and configured to perform eccentric
10 rotation in the cylinder 21 chamber. The compression mechanism unit 2 also
includes two end plates 10b and 11b disposed on both end surfaces of the cylinder 21
in the axial direction of the rotary shaft 4, and the vane 23 protruding into the cylinder
21 chamber of the cylinder 21, and configured to be brought into contact with the
rotary piston 22 to form the compression chamber 24b in the cylinder 21 chamber.
15 The compression mechanism unit 2 further includes the seal plate 40 configured to
move in conjunction with the eccentric rotation of the rotary piston 22, and configured
to close a portion of the injection port 30a that is located inward of the inner peripheral
surface 22c of the rotary piston 22, the injection port 30a being formed in one end
plate 10b out of the two end plates 10b. The seal plate 40 is separated from the
20 rotary piston 22, is rotatable relative to the rotary piston 22, and has the through hole
41 through which the main shaft portion 4a of the rotary shaft 4 is caused to pass, the
through hole 41 being open outward in the radial direction.
[0057]
As described above, the rotary compressor has a structure that includes the
25 seal plate 40 configured to close a portion of the injection port 30a that is located
inward of the inner peripheral surface of the rotary piston 22, so that the injection port
30a is prevented from facing the inner side of the rotary piston 22. The seal plate 40
is separated from the rotary piston 22, is rotatable relative to the rotary piston 22, and
has the through hole 41 through which the main shaft portion 4a of the rotary shaft 4
30 is caused to pass, the through hole 41 being open outward in the radial direction.

23
The through hole 41 is open outward in the radial direction in this manner and hence,
the main shaft portion 4a of the rotary shaft 4 can be disposed at a position close to
the open side of the through hole 41, thus allowing the eccentricity of the eccentric
shaft portion 4b to be adjusted by changing the position of the main shaft portion 4a of
5 the rotary shaft 4 in the through hole 41. Accordingly, in the case where the main
shaft portion 4a is moved toward the open side of the through hole 41 until the main
shaft portion 4a is brought into contact with the inner peripheral surface of the rotary
piston 22, it is possible to increase the eccentricity of the eccentric shaft portion 4b of
the rotary shaft 4 to a maximum.
10 [0058]
In Embodiment, the main shaft portion 4a of the rotary shaft 4 passes through
the through hole 41 at a position closer to the open side of the through hole 41 of the
seal plate 40 than the center axis of the rotary piston 22. The eccentric shaft portion
4b of the rotary shaft 4 is eccentric from a position coaxial with the main shaft portion
15 4a in a direction opposite to the open side of the through hole 41 within a range of
equal to or less than a difference between the radius of the main shaft portion 4a and
the radius of the eccentric shaft portion 4b.
[0059]
With such a configuration, it is possible to obtain a rotary compressor where the
20 eccentricity of the eccentric shaft portion 4b of the rotary shaft 4 is adjusted within a
range of equal to or less than the difference between the radius of the main shaft
portion 4a and the radius of the eccentric shaft portion 4b.
[0060]
In Embodiment, the seal plate 40 moves in conjunction with the eccentric
25 rotation of the rotary piston 22 while maintaining a posture where the open side of the
through hole 41 faces in a direction opposite to the eccentric direction of the eccentric
shaft portion 4b.
[0061]
With such a configuration, a portion of the injection port 30a that is located
30 inward of the inner peripheral surface 22c of the rotary piston 22 can be closed with

24
the seal plate 40.
[0062]
In Embodiment, the compression mechanism unit 2 includes two compression
units each of which includes the cylinder 21, the rotary piston 22, and the vane 23,
5 and that are arranged in the axial direction, and the compression mechanism unit 2
further includes the intermediate plate 12 as another end plate 10b in addition to the
two end plates 10b. Assuming that one of the two compression units arranged in the
axial direction is the first compression unit 20A, and the other of the two compression
units arranged in the axial direction is the second compression unit 20B, the two end
10 plates 10b are respectively disposed on one side of the first compression unit 20A in
the axial direction and the other side of the second compression unit 20B in the axial
direction, and the intermediate plate 12 is disposed between the first compression
unit 20A and the second compression unit 20B. The refrigerant at intermediate
pressure is introduced into the compression chamber 24b of each of the two
15 compression mechanism units 2 through two injection ports 30a, and both of the two
injection ports 30a are formed in the intermediate plate 12 or are respectively formed
in the two end plates 10b, or one of the two injection ports 30a is formed in one of the
two end plates 10b and the other of the two injection ports 30a is formed in the
intermediate plate 12.
20 [0063]
As described above, the compression mechanism unit 2 may have a
configuration that includes two compression units. In the case of such a
configuration, it is sufficient to adopt a configuration where both of the injection ports
30a corresponding to the respective compression units are formed in the intermediate
25 plate 12, a configuration where the injection ports 30a are respectively formed in the
two end plates 10b, or a configuration where one of the injection ports 30a is formed
in one of the two end plates 10b and the other of the injection ports 30a is formed in
the intermediate plate 12.
Reference Signs List
30 [0064]

25
1: sealed container, 2: compression mechanism unit, 3: electric motor unit, 3a:
stator, 3b: rotor, 4: rotary shaft, 4a: main shaft portion, 4aa: outer peripheral surface,
4b: eccentric shaft portion, 5: discharge pipe, 6: oil separator, 7: injection pipe, 8:
suction muffler, 10: upper bearing, 10a: bearing portion, 10b: end plate, 11: lower
5 bearing, 11a: bearing portion, 11b: end plate, 12: intermediate plate, 13: upper
discharge muffler, 14: lower discharge muffler, 20: compression unit, 20A: first
compression unit, 20B: second compression unit, 21: cylinder, 22: rotary piston, 22a:
end surface, 22b: recessed portion, 22c: inner peripheral surface, 23: vane, 23a: vane
groove, 24: cylinder chamber, 24a: suction chamber, 24b: compression chamber, 26:
10 suction port, 27: discharge port, 30: injection flow passage, 30a: injection port, 40:
seal plate, 41: through hole, 41a: inner surface, 50: space portion, 60: annular region,
104: rotary shaft, 104a: main shaft portion, 104aa: outer peripheral surface, 104b:
eccentric shaft portion, 122: rotary piston, 122a: inner peripheral surface, 130a:
injection port, 140: sealing portion.

We Claim:
[Claim 1]
5 A rotary compressor including a compression mechanism unit configured to
compress refrigerant in a compression chamber, wherein refrigerant at an
intermediate pressure is injected into the compression chamber of the compression
mechanism unit from an injection port, wherein
the compression mechanism unit includes:
10 a rotary shaft including a main shaft portion and an eccentric shaft portion;
a cylinder having a cylinder chamber;
a rotary piston mounted on the eccentric shaft portion of the rotary shaft and
configured to perform eccentric rotation in the cylinder chamber;
two end plates disposed on both end surfaces of the cylinder in an axial
15 direction of the rotary shaft;
a vane protruding into the cylinder chamber of the cylinder, and configured to
be brought into contact with the rotary piston to form the compression chamber in the
cylinder chamber; and
a seal plate configured to move in conjunction with the eccentric rotation of the
20 rotary piston, and configured to close a portion of the injection port that is located
inward of an inner peripheral surface of the rotary piston, the injection port being
formed in one end plate of the two end plates, and
the seal plate is separated from the rotary piston, is rotatable relative to the
rotary piston, and has a through hole through which the main shaft portion of the
25 rotary shaft is caused to pass, the through hole being open outward in a radial
direction.
30

27
[Claim 2]
The rotary compressor of claim 1, wherein the main shaft portion of the rotary
shaft passes through the through hole at a position closer to an open side of the
5 through hole of the seal plate than a center axis of the rotary piston, and
the eccentric shaft portion of the rotary shaft is eccentric from a position coaxial
with the main shaft portion in a direction opposite to the open side of the through hole
within a range of equal to or less than a difference between a radius of the main shaft
portion and a radius of the eccentric shaft portion.
10 [Claim 3]
The rotary compressor of claim 1 or claim 2, wherein the seal plate moves in
conjunction with the eccentric rotation of the rotary piston while maintaining a posture
where the open side of the through hole faces in a direction opposite to an eccentric
direction of the eccentric shaft portion.
15 [Claim 4]
The rotary compressor of any one of claims 1 to 3, wherein
the compression mechanism unit includes two compression units each of which
includes the cylinder, the rotary piston, and the vane, and that are arranged in the
axial direction, and the compression mechanism unit further includes an intermediate
20 plate as another end plate in addition to the two end plates,
assuming that one of the two compression units arranged in the axial direction
is a first compression unit, and an other of the two compression units arranged in the
axial direction is a second compression unit,
the two end plates are respectively disposed on one side of the first
25 compression unit in the axial direction and an other side of the second compression
unit in the axial direction, and the intermediate plate is disposed between the first
compression unit and the second compression unit, and

30

28
two injection ports, through which the refrigerant at the intermediate pressure is
introduced into the compression chamber of each of the two compression mechanism
units, and are both formed in the intermediate plate or are respectively formed in the
two end plates, or one of the two injection ports is formed in one of the two end
5 plates, and an other of the two injection ports is formed in the intermediate plate.