Rotary compressor

Details Rotary compressor Rotary compressor

1998-08-28

2001-04-10

Dolinar, Andrew M. (Department: 3747)

Pumps

With muffler acting on pump fluid

C181S403000

Reexamination Certificate

active

06213732

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a compressor used in an air conditioner or the like, and more particularly to a rotary piston type rotary compressor.
BACKGROUND OF THE INVENTION
The structure of a rolling piston type rotary compressor widely used in the compressor for an air conditioner is known as represented by a longitudinal sectional view in FIG.
8
and lateral sectional view of compression element in FIG.
9
. In FIG.
8
and
FIG. 9
, the compressor comprises a motor
102
accommodated in an enclosed container
101
, and a compression unit
103
driven by this motor
102
. A drive shaft
106
of the compression unit
103
is coupled to the motor
102
, and is supported by a main bearing
108
and a subsidiary bearing
109
disposed at both sides of a cylinder block
111
. The motor
102
includes a stator
104
, a rotor
105
, and the drive shaft
106
. Inside of the cylinder block
111
incorporating a cylinder
119
, a roller
110
externally fitted to a crank unit
107
eccentric from the main shaft of the drive shaft
106
is disposed closely to the inner wall of the cylinder
119
. Thus, a compression chamber
115
is formed. In a guide groove
112
of the cylinder block
111
, a blade
114
and a spring device
113
for thrusting the leading end of the blade
114
to the roller
110
are disposed, and the compression chamber
115
is divided into the suction side and compression side. In the cylinder block
111
, on the boundary of the blade
114
, a suction port
116
opening to the cylinder
119
and a discharge port
117
are provided. An accumulator
160
for accumulating the low pressure side refrigerant is connected to the suction port
116
.
In the rotary compressor in such constitution having one compression chamber
115
, since compression torque fluctuations are significant, vibrations are large and the compressor piping system may be broken.
To solve such a problem, as shown in
FIG. 10
, a rolling piston type rotary compressor having two compression chambers in a cylinder
219
has been proposed. In
FIG. 10
, a first blade
221
and a first spring device
222
are disposed in a first guide groove
220
provided in a cylinder block
211
, and a second blade
224
and a second spring device
225
are disposed in a second guide groove
223
. Thus, a first compression chamber
226
and a second compression chamber
227
are provided. In the first compression chamber
226
, a first suction port
228
and a first discharge port
229
are opened, and in the second compression chamber
227
, a second suction port
230
and a second discharge port
231
are opened.
In the compressor in such constitution having two blades, the relation between the shaft rotating angle and required torque is shown in FIG.
11
. As shown in
FIG. 11
, the compression torque action range per revolution of a drive shaft
206
is divided into two sections, and the compressor vibrations are reduced to half as compared with the compressor shown in FIG.
8
. This constitution is disclosed in Japanese Laid-open Patent No. 63-208688.
On the other hand, the compressor having the first suction port
228
and second suction port
230
in the cylinder block
211
is constituted, for example, as shown in
FIG. 12
, in which a first accumulator
218
and a second accumulator
214
are disposed at the suction side.
To simplify the suction piping system, a constitution as shown in
FIG. 13
is proposed in Japanese Laid-open Patent No. 1-249977. In
FIG. 13
, an accumulator
350
penetrates through a side wall of an enclosed container
301
, and is connected to a suction port
349
a
of a first compression chamber. To a suction port
349
b
of a second compression chamber, the suction port
349
a
is communicating through a communication pipe
363
in the enclosed container
301
. The passage entering the second compression chamber is communicating with the second compression chamber by detour. The communication pipe
363
is composed by evading the bearing boss of a main bearing
334
for supporting a drive shaft
336
. That is, the length of the passage entering the second compression chamber has a path longer than the length of the passage entering the first chamber. Furthermore, the gas leaving the accumulator
350
is divided into two paths to get into the first compression chamber and second compression chamber respectively. In this case, the two divided flows of the gas are not uniform. In such conventional constitution, as mentioned below, there was a first problem relating to the flow of suction gas.
The principle of compression of the compressor forming two compression chambers in the cylinder by disposing two blades in one cylinder block is as shown in FIG.
6
. That is, the shaded area in
FIG. 6
(
a
) shows the state of maximum suction stroke volume in the compression chamber. The shaded area in
FIG. 6
(
b
) shows the compression chamber immediately before closure of the suction port in the state of minimum suction stroke volume in the compression chamber, which is reduced from the state of the maximum suction stroke volume in
FIG. 6
(
a
). This decrease in the suction stroke volume means that the suction gas flows back to the suction piping system through the suction port. The shaded area in
FIG. 6
(
c
) shows the state of substantial start of compression after closure of the suction port. The shaded area in
FIG. 6
(
d
) shows the state of discharge from the compression chamber through suction port and suction valve as a result of elevation of compression chamber pressure. Thus, flow-in and counter-flow of suction gas occur in the suction and compression strokes. Accordingly, the suction route is unevenly divided into two flows as shown in
FIG. 13
, and the path lengths of two divided flows are different, and in such constitution, therefore, pulsations occurring in the suction passage interfere with each other, thereby resulting in increase of suction passage resistance and significant drop of compression efficiency.
There was also a second problem.
FIG. 7
shows a pressure state in each cylinder at each compression stroke. In
FIG. 7
(
a
), the pressure in the cylinder opposite to the second plate
224
is low on both sides, and the pressure in the cylinder opposite to the first blade
221
is low on one side, and high on the other. Therefore, the roller side leading end of the second blade
224
and the roller
210
contact with each other by both thrusting forces, that is, the thrusting force of the second spring device
225
acting on the second blade
224
and the thrusting force by the differential pressure of the discharge pressure and suction pressure.
On the other hand, the roller side leading end of the first blade
221
and the roller
210
contact with each other by the combined thrusting force of the thrusting force of the first spring device
222
acting on the first blade
221
, and the differential thrusting force of the thrusting force by refrigerant gas pressure distribution from the cylinder inside acting on the roller side leading end of the first blade (the thrusting force on the basis of the distribution rate of the compression intermediate pressure and the distribution rate of the suction pressure) and the thrusting force by discharge pressure. The contacting force of the first blade
221
and roller
210
and the contacting force of the blade
1141
and roller
110
in
FIG. 9
are equal to each other.
In
FIG. 7
(
b
), the pressure in the cylinder opposite to the first blade
221
and second blade
224
is low (suction pressure) on both sides. Therefore, the first blade
221
and the roller
210
of the roller side leading end of the second blade
224
contact with each other by receiving the same thrusting force as the second blade
224
in
FIG. 7
(
a
).
In
FIG. 7
(
c
), the pressure in the cylinder opposite to the first blade
221
is low on both sides, and the pressure in the cylinder opposite to the second blade
224
is low on one side and high on the other. Therefore, the roller side leading end of the first bl

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