Rotary expansible chamber devices – Working member has planetary or planetating movement – With relatively movable partition member
Reexamination Certificate
1999-09-10
2001-07-17
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Working member has planetary or planetating movement
With relatively movable partition member
C418S179000, C418S270000
Reexamination Certificate
active
06261073
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a compressor for a refrigeration system and, more specifically, to improvements in the dimensional relation between the recesses and a discharge port of a bearing member in a compressor for a refrigeration system.
2. Description of the Related Art
A general rotary compressor shown in
FIG. 8
for use in a refrigeration system comprises a compressing mechanism
21
, an electric motor
22
and a sealed case
20
containing the compressing mechanism
21
and the electric motor
22
. The electric motor
22
has a rotor
24
, a drive shaft (crankshaft)
2
fixed to the rotor
24
to drive the compressing mechanism
21
. The compressing mechanism
21
has a pair of cylinders
1
and
1
′. The drive shaft
2
is extended through the cylinders
1
and
1
′. Rollers
10
are placed in the cylinders
1
and
1
′, respectively. The rollers
10
roll along the inner surfaces of the side walls of the cylinders
1
and
1
′, respectively.
A main bearing member
3
and an auxiliary bearing member
3
′ are disposed contiguously with the pair of cylinders
1
and
1
′, respectively. The bearing member
3
and the auxiliary bearing member
3
′ are basically similar in construction. Therefore only the bearing member
3
is shown in FIG.
9
and only the bearing member
3
will be described. As shown in
FIG. 9
, the bearing member
3
has a flange
5
joined to an end surface of the corresponding cylinder
1
(FIG.
8
), and a bearing part
6
supporting the drive shaft
2
. As shown in
FIGS. 10 and 11
, a discharge port
4
is formed through the flange
5
.
FIG. 11
is a fragmentary longitudinal sectional view taken on line XI—XI passing the center axis
6
c of the bearing part
6
and the center axis
4
c of the discharge port
4
in FIG.
10
. As shown in
FIG. 9
, a discharge valve element
7
is attached to the flange
5
of the bearing member
3
to open and close the discharge port
4
. A valve holder
12
is attached to the flange
5
to limit the opening of the valve element
7
. A recess
8
corresponding to the discharge valve element
7
is formed in the flange
5
. As shown in
FIG. 11
, a portion of the bottom surface
80
of the recess
8
around the outlet end of the discharge port
4
is raised to form a valve seat
9
.
The conventional compressor for a refrigeration system as mentioned above has the following problems. As the thickness T (
FIG. 11
) of the valve seat
9
increases, the amount of the refrigerant remaining in the discharge port
4
increases after the completion of a discharge stroke. The increased amount of the refrigerant remaining in the discharge port
4
reduces the coefficient of performance (COP) of the refrigeration system and increases noise generated by the operating compressor. However, the thickness T of the valve seat
9
is equal to the thickness H of the bottom wall of the recess
8
or is greater than the same to prevent cavitation. Therefore, if the thickness T of the valve seat
9
is reduced simply, the thickness H of the bottom wall of the recess
8
is reduced accordingly. If the thickness H of the bottom wall of the recess
8
is reduced, the deflection of the bottom wall of the recess
8
due to the difference between pressures acting respectively on the opposite sides of the bottom wall of the recess
8
increases.
If the bottom wall of the recess
8
is deflected, the refrigerant leaks to further reduce the COP and it is possible that the bearing members
3
and
3
′ are broken. With a view to forming the valve seat
9
in a sufficient thickness T and surely preventing the deflection of the bottom wall of the recess
8
, the diameter B of the discharge port
4
and the thickness T of the valve seat
9
are determined so that the ratio T/B>0.3 in the conventional compressor.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a compressor for a refrigeration system, comprising a bearing member having a flange provided with a recess and a valve seat having a thickness smaller than that of the valve seat of the bearing member of an equivalent conventional compressor and formed so as to suppress the deflection of the bottom wall of the recess and to prevent the breakage of the bearing part; and capable of enabling the refrigeration system to operate at an improved COP and of reducing the noise generated by the operating compressor.
According to a first aspect of the present invention, a compressor for a refrigeration system comprises a cylinder having a shape substantially resembling a circular cylinder; a drive shaft extended through the cylinder; a bearing member joined to an end of the cylinder, having a flange provided with a discharge port and a bearing part supporting the drive shaft and a discharge valve element held on the flange to open and close the discharge port; wherein the flange of the bearing member has a recess corresponding to the discharge valve element, and a valve seat formed by raising a portion of the bottom surface of the recess around the discharge port, the ratio H/A≧0.07, where H is the thickness of the bottom wall of the recess and A is the width of the recess in a longitudinal section taken on line passing the center axis of the bearing part and the center axis of the discharge port, and the ratio T/B≦0.3, where T is the thickness of the valve seat and B is the diameter of the discharge port.
When the flange, the recess, the discharge port and the valve seat are formed so that H/A≧0.07 and T/B≦0.3, the valve seat can be formed in the thickness T smaller than that of the valve seat of the bearing member of an equivalent conventional compressor without increasing the deflection of the bottom wall of the recess, the compressor improves the COP of the associated refrigeration system and reduces noise generated by the operating compressor.
In this compressor, the ratio B/A, where B is the diameter of the discharge port and A is the width of the recess, may be 0.2 or above. When the condition B/A ≧0.2 is satisfied, the deflection of the bottom wall of the recess can further reduced.
Preferably, the bearing member is formed of a material having a Young's modulus of 70 GPa or above. When the bearing member is formed of such a material, the deflection of the bottom all of the recess of the flange of the bearing member can further reduced and the reduction of the COP can be prevented.
The material having a Young's modulus of 70 GPa or above may be a cast iron, aluminum or an iron-base sintered metal.
According to a second aspect of the present invention, a compressor for a refrigeration system comprises a cylinder having a shape substantially resembling a circular cylinder; a drive shaft extended through the cylinder; a bearing member joined to an end of the cylinder, having a flange provided with a discharge port and a bearing part supporting the drive shaft; and a discharge valve element held on the flange to open and close the discharge port; wherein the flange of the bearing member is provided with a recess corresponding to the discharge valve element, a valve seat formed by raising a portion of the bottom surface of the recess around the discharge port, and a reinforcing part having a thickness greater than that of the bottom wall of the recess and formed in a portion of the bottom wall of the recess between the valve seat and the bearing part.
The thickness of the reinforcing part formed in the recess may be increased continuously toward the bearing part.
The thickness of the reinforcing part formed in the recess may be increased stepwise toward the bearing part.
In the foregoing compressors according to the present invention, the deflection of the bottom wall of the recess of the flange of each bearing member is suppressed and, consequently, the leakage of the gaseous refrigerant can be limited to the least unavoidable extent even if the compressors are used for compressing a refrigerant of a pressure higher than tha
Foley & Lardner
Kabushiki Kaisha Toshiba
Vrablik John J.
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