Pumps – Three or more cylinders arranged in parallel – radial – or...
Reexamination Certificate
1999-09-13
2001-01-30
Walberg, Teresa (Department: 3742)
Pumps
Three or more cylinders arranged in parallel, radial, or...
C417S571000
Reexamination Certificate
active
06179576
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a reciprocating compressor, and, more specifically, to a reciprocating compressor with an improved structure of a suction chamber suitable for use in a refrigerating cycle of an air conditioner for vehicles.
2. Description of the Prior Art
Generally, in a reciprocating compressor, a gas is introduced from a suction chamber into a reciprocating mechanism having a plurality of bores and a plurality of pistons. The compressed gas by the reciprocating mechanism is introduced into a discharge chamber and then discharged therefrom. The suction chamber and the discharge chamber usually are formed in a cylinder head.
For example, as depicted in
FIG. 4
, discharge chamber
101
is formed at a radially central portion of cylinder head
102
. Suction chamber
103
is formed around discharge chamber
101
to extend in the circumferential direction of discharge chamber
101
at a radially outer portion of discharge chamber
101
. Partition wall
104
separates suction chamber
103
from discharge chamber
101
. Outer wall
105
defines suction chamber
103
. A gas is introduced into suction chamber
103
through suction port
106
. The gas is displaced from suction chamber
103
into bores
107
in a cylinder block (not shown). The compressed gas within each bore
107
is displaced into discharge chamber
101
, and then discharged from discharge chamber
101
through discharge port
108
.
Partition wall
104
has a plurality of concave surfaces
104
a
and a plurality of convex surfaces
104
b
on its radially outer surface. Concave surfaces
104
a
and convex surfaces
104
b
are arranged alternately to form a continuous convex/concave curved surface. Outer wall
105
has a plurality of portions
109
projecting toward the respective concave surfaces
104
a
of partition wall
104
on its radially inner surface
105
a
. Projecting portions
109
are arranged at a predetermined interval in the circumferential direction of outer wall
105
. A screw hole
110
is defined in each projecting portion
109
. Other than projecting portions
109
, the thickness of outer wall
105
is substantially constant.
In a known compressor, suction flow conditions of the gas in bores
107
tend to become nonuniform because suction chamber
103
extends in the circumferential direction and the gas is introduced into suction chamber
103
through suction port
106
, which is typically a single port. This condition may cause a decrease of refrigeration ability due to the reduction of the volume efficiency of the suction gas and the occurrence of vibration and noise due to pulsating suction. In particular, as depicted in
FIG. 4
, two gaps, which have differing widths L
1
and L
2
, are formed in suction chamber
103
. Width L
1
is formed between the inner surface
105
a
of outer wall
105
and the convex surface
104
b
of partition wall
104
. Width L
1
is greater than width L
2
, which is formed between the inner surface of projecting portion
109
of outer wall
105
and the convex surface
104
b
of partition wall
104
. Therefore, a gap having width L
2
acts as a throttle against the gas flow in suction chamber
103
. Consequently, as depicted by arrow A in
FIG. 4
, a break away flow A may be generated with the gas flow in suction chamber
103
at a position immediate downstream of the gap portion having width L
2
in the direction of the gas flow, or at a position of the downstream side of projecting portion
109
. Such a break away flow A may increase the pressure loss in the gas flow, may decrease suction efficiency into each bore
107
. Further, the volume of the gas sucked into the respective bores
107
may become nonuniform. As a result, in a refrigeration system, the refrigeration ability may decrease. Moreover, break away flow A may cause a pulsation of suction, and it may increase vibration and noise within the compressor.
Japanese Utility Model Laid-Open 61-145884 or JP-A-7-139463 discloses a structure wherein a suction chamber, or a suction path, is formed so as to cross a discharge chamber at a central portion over the discharge chamber, or a structure wherein the height of a narrow portion of a suction chamber is enlarged by heightening a partition wall between the discharge chamber and the suction chamber. However, if a suction chamber is formed to cross over a discharge chamber, then it may be necessary to reduce the height of a discharge chamber in the axial direction of the compressor, or to enlarge the height of the suction chamber. If the narrow portion of the suction chamber is enlarged in the axial direction of the compressor, then the axial length of the entire compressor may increase, and may cause a deterioration of workability for mounting the compressor on a vehicle. Further, in both structures, the weight of a compressor may increase accompanying with the increase of the axial length.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an improved structure for a reciprocating compressor that may attain a more uniform gas flow in a suction chamber, and may attain a uniform volume of gas sucked from the suction chamber into the bores, thereby improving the volume efficiency of suction that increases the operability of the compressor and reduces the occurrence of vibration and noise.
It is another object of the present invention to provide an improved structure for a reciprocating compressor that may improve the gas flow in the suction chamber without enlarging the axial length of the compressor, thereby providing a compressor having a reduced weight.
To achieve the foregoing and other objects, a reciprocating compressor according to the present invention is herein provided. The reciprocating compressor includes a discharge chamber provided at a radially central portion of the compressor, a suction chamber extending in a circumferential direction of the discharge chamber at a radially outer portion around the discharge chamber, and a reciprocating mechanism for compressing a gas sucked from the suction chamber and discharging the compressed gas into the discharge chamber. The reciprocating compressor comprises a partition wall separating the suction chamber from the discharge chamber, and an outer wall extending along the suction chamber with a gap relative to the partition wall for defining the suction chamber. The outer wall has a plurality of portions projecting toward the partition wall on a radially inner surface of the outer wall. The plurality of projecting portions are arranged at an interval in a circumferential direction of the outer wall. Each of the projecting portions has an arc-projecting surface facing the partition wall, and an inclined surface facing the partition wall and extending from each side of the arc-projecting surface to the radially inner surface of the outer wall.
The reciprocating compressor may be constructed as an inclined plate type compressor. For example, the reciprocating compressor includes a center housing having a crank chamber therein, and a cylinder block with a plurality of bores at a rear end of the center housing. A front housing is provided at a front end of the center housing for closing the crank chamber. A drive shaft is rotatably supported, for example, by the cylinder block and the front housing. An inclined plate mechanism is provided on the drive shaft. A plurality of pistons are provided, respectively, in the plurality of bores and reciprocated by an operation of the inclined plate mechanism. A cylinder head connects to a rear end of the cylinder block via a valve plate. The cylinder head includes the partition wall, the outer wall, the plurality of projecting portions, the arc-projecting surfaces and the inclined surfaces.
In the reciprocating compressor, a plurality of convex surfaces and a plurality of concave surfaces may be formed on an radially outer surface of the partition wall. The convex surfaces and the concave surfaces may be arranged alternately in a circumferential direction of the radi
Baker & Botts L.L.P.
Fastovsky Leonid
Sanden Corporation
Walberg Teresa
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