Rotary expansible chamber devices – Multistage – One working chamber stage encircles another
Reexamination Certificate
2001-04-30
2002-07-30
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Multistage
One working chamber stage encircles another
C418S055100, C418S059000, C418S220000
Reexamination Certificate
active
06425744
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a compressor constituting a refrigerating cycle of, for example, an air conditioner, particularly, to a helical blade type compressor for continuously compressing an object fluid, i.e., fluid to be compressed, in an axial direction of a cylinder.
A refrigerating cycle is incorporated in, for example, a domestic air conditioner, a refrigerator and a refrigerating show case. The refrigerating cycle is provided with a compressor for compressing a cooling medium. A reciprocating type compressor and a rotary compressor are popular as a compressor of this kind. In recent years, a helical blade type compressor employing a helical blade in the compressing mechanism portion is being developed.
The helical blade type compressor permits eliminating the defective sealing inherent in the conventional reciprocating type or rotary compressor and also permits improving the sealing properties with a relatively simple construction. In addition, manufacture and assembly of parts are facilitated.
The helical blade type compressor can be classified into two types. In one of the two types of the helical blade type compressor, a roller making an eccentric rotation is housed in a stationary cylinder. Also, a blade is engaged with a blade groove formed in the outer circumferential surface of the roller. Further, an object fluid, i.e., a cooling medium gas, is introduced into a compression chamber defined by the cylinder, the roller and the blade so as to compress the cooling medium gas.
FIG. 10
shows the construction of the conventional helical blade type compressor outlined above. As shown in the drawing, the compressor comprises a hermetic casing
1
, a compressing mechanism section
2
housed in the hermetic casing
1
, and a motor section
4
which is also housed in the hermetic casing
1
. The compressing mechanism section
2
, which is driven by the motor section
4
via a rotary shaft
3
, includes a cylinder
5
fixed within the hermetic casing
1
, a roller
6
eccentrically housed in the cylinder
5
, and a helical blade
7
interposed between the roller
6
and the cylinder
5
. A plurality of compression chambers
8
are defined by the helical blade
7
between the cylinder
5
and the roller
6
so as to extend in the axial direction of the cylinder
5
.
The helical blade
7
is wound about a helical blade groove
7
a
formed in the outer circumferential surface of the roller
6
and is hermetically brought into contact with the inner circumferential surface of the cylinder
5
. Also, the roller
6
is mounted to a crank portion
3
a
of the rotary shaft
3
. The rotary shaft
3
, which constitutes the output shaft of the motor section
4
, is rotated in accordance with driving of the motor section
4
, with the result that the roller
6
mounted to the crank portion
3
of the rotary shaft
3
is eccentrically rotated about the rotary shaft
3
.
In the blade supporting mechanism in which the helical blade
7
is engaged with the blade groove
7
a
formed in the outer circumferential surface of the roller
6
, the roller
6
is eccentrically rotated within the cylinder
5
. In this mechanism, a revolution preventing mechanism
9
is mounted in order to prevent the roller
6
from being revolved about its own axis and to permit the roller
6
to be eccentrically rotated about the rotary shaft
3
. An Oldham ring or the like is used as the revolution preventing mechanism.
In the other type of the conventional helical blade type compressor, a roller is eccentrically arranged within a rotating cylinder. In this case, a helical blade is engaged with a helical blade groove formed in the outer circumferential surface of the roller. The roller is rotated in synchronism with rotation of the cylinder, and a cooling medium gas is introduced into a compression chamber defined among the cylinder, the roller and the blade so as to be compressed in the compression chamber.
However, any of the two types of the conventional helical blade type compressor described above gives rise to problems. Specifically, in the former type, a blade groove with which the blade is engaged is formed on the outer circumferential surface of the roller, leading to a large thickness of the roller wall and, thus, to a large rotary mass. It follows that a large vibration is generated during rotation of the roller about the rotary shaft.
Further, since the roller
6
is rotated about the rotary shaft
3
with the helical blade
7
engaged with the blade groove
7
a
formed on the outer circumferential surface of the roller, the revolution preventing mechanism
9
is required for preventing the roller
6
from being revolved about its own axis. Therefore, the number of parts is increased and the sliding member is also increased. As a result, the compressor function is impaired and detrimental effects are given to the compressor performance. Further, the manufacturing cost of the compressor is increased. What should also be noted is that the assembling structure of the compressing section
2
is made complex, making it laborious to assemble the compression section
2
.
In the latter type, a blade groove is also formed on the outer circumferential surface of the roller which is rotated in synchronism with rotation of the cylinder, leading to a thick roller wall and, thus, to an increased rotary mass of the roller. It follows that a large vibration is generated during rotation of the roller.
Further, the helical blade type compressor is required to compress a large volume of an object fluid. If the compressor is enlarged for compressing a large volume of the object fluid, the rotary mass and vibration of the roller are further increased, making it necessary to use a large counter balancer for suppressing the vibration. In this case, a problem is generated in respect of the mounting space of the large counter balancer. In addition, if the roller is rotated at a high speed by using an inverter, the rotary shaft is bent so as to increase the vibration, and the bearing is abraded and damaged in an early stage.
Under the circumstances, it is required to decrease the wall thickness of the roller in any type of the helical blade type compressor so as to diminish the rotary mass. However, it is impossible to meet the requirement as far as a blade groove is formed on the outer circumferential surface of the roller.
BRIEF SUMMARY OF THE INVENTION
A first object of the present invention is to provide a helical blade type compressor which permits suppressing the vibration by diminishing the eccentric mass of a rotary body.
A second object of the present invention is to provide a helical blade type compressor which permits decreasing the rotary mass of the rotary body so as to increase the volume of the object fluid without impairing the manufacturing properties of the compressor.
A third object of the present invention is to provide a helical blade type compressor which permits decreasing the rotary mass of the rotary body so as to increase the volume of the object fluid and also permits increasing the compression capacity.
Further, a fourth object of the present invention is to provide a helical blade type compressor which permits simplifying the assembling structure of the helical compression section so as to facilitate the assembly of the compressor.
According to a first aspect of the present invention, there is provided a helical blade type compressor, comprising a stationary cylinder, a roller eccentrically arranged within the cylinder, a helical compression section including a helical blade serving to divide the free space between the roller and the cylinder into a plurality of compression chambers arranged in the axial direction of the cylinder, and a rotary shaft serving to eccentrically rotate the roller within the cylinder, wherein a helical blade groove is formed on the inner circumferential surface of the cylinder and the helical blade is engaged with the helical groove such that an object fluid is moved in the axial direction of the cylinder so as to be compressed in acc
Fujiwara Takayoshi
Fukuda Tetsuo
Ozu Masao
Pillsbury & Winthrop
Vrablik John J.
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