Pumps – Expansible chamber type – Having pumping chamber pressure responsive distributor
Reexamination Certificate
2002-02-28
2003-12-09
Tyler, Cheryl J. (Department: 3746)
Pumps
Expansible chamber type
Having pumping chamber pressure responsive distributor
C417S269000, C137S856000
Reexamination Certificate
active
06659742
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to reciprocating compressors for use in an air conditioning system of a vehicle. More particularly, the invention relates to reciprocating compressors having an improved refrigerant suction efficiency.
2. Description of Related Art
Reciprocating compressors may include swash plate-type compressors, wobble plate-type compressors, or the like. Referring to
FIG. 1
, a known, wobble plate-type compressor
100
is described. Compressor
100
may comprise a cylinder block
1
, a front housing
2
, a rear housing
3
, and a drive shaft
7
. Drive shaft
7
may pass through the center of front housing
2
and the center of cylinder block
1
. Drive shaft
7
also may be rotatably supported by front housing
2
and by cylinder block
1
via a pair of bearings
8
a
and
8
b
mounted in front housing
2
and cylinder block
1
, respectively. A plurality of cylinder bores
5
may be formed within cylinder block
1
and also may be positioned equiangularly around an axis of drive shaft
7
. Moreover, a piston
16
may be slidably positioned within each cylinder bore
5
, such that pistons
16
reciprocate in a direction parallel to the axis of drive shaft
7
.
Compressor
100
also may comprise a driving mechanism (not numbered). The driving mechanism may comprise drive shaft
7
, a rotor
9
, a crank chamber
4
, and a swash plate
6
. Specifically, rotor
9
is fixed to drive shaft
7
, such that drive shaft
7
and rotor
9
rotate together. Crank chamber
4
is formed between front housing
2
and cylinder block
1
, and swash plate
6
may be positioned inside crank chamber
4
. Swash plate
6
may include a penetration hole
6
c
formed therethrough at a center portion of swash plate
6
, and drive shaft
7
may extend through penetration hole
6
c.
Moreover, rotor
9
and swash plate
6
may be connected by a hinge mechanism
11
comprising a pin (not numbered) and an oblong hole (not numbered) formed through hinge mechanism
11
. Hinge mechanism
11
allows the tilt angle of swash plate
6
to vary with respect to drive shaft
7
. The drive mechanism also may comprise a substantially ring-shaped wobble plate
14
and a connection rod
15
, and compressor
100
further may comprise a rotation prevention mechanism
17
. Wobble plate
14
may be rotatably attached to swash plate
6
by a thrust bearing
12
and a radial bearing
13
, and may engage rotation prevention mechanism
17
. Wobble plate
14
also may be connected to piston
16
by rod
15
and a pair of ball joints
15
a
and
15
b.
Moreover, rotation prevention mechanism
17
may prevent wobble plate
14
from rotating about the axis of drive shaft
7
. Nevertheless, ball joints
15
a
and
15
b
may allow wobble plate
14
to move back and forth in a wobbling motion.
Referring to
FIGS. 1-3
, compressor
100
also may comprise a valve plate
20
positioned between cylinder block
1
and rear housing
3
, and a suction chamber
18
formed between rear housing
3
and valve plate
20
. Valve plate
20
may include a suction hole
20
a
formed therethrough, which may allow suction chamber
18
to be in fluid communication with cylinder bore
5
, such that a fluid, e.g., a refrigerant introduced from an external refrigerant circuit (not shown), may flow from suction chamber
18
to cylinder bore
5
. Valve plate
20
may comprise a suction valve reed
21
formed on a side, e.g., the left side, of valve plate
20
. Suction valve reed
21
regulates the fluid communication between suction chamber
18
and cylinder bore
5
. Moreover, a limiting recess
23
′ formed in cylinder block
1
and having a bottom surface
23
b
may limit the extent to which suction valve reed
21
may bend when fluid flows from suction chamber
18
to cylinder bore
5
. Limiting recess
23
′ comprises an arced segment formed symmetrically about a center axis (X) of suction valve reed
21
, such that axis (X) also is the center axis of limiting recess
23
′.
Compressor
100
further may comprise a discharge chamber
19
, and valve plate
20
further may include a discharge hole
20
b
formed therethrough. Discharge hole
20
b
may allow cylinder bore
5
to be in fluid communication with discharge chamber
19
, such that a fluid, e.g., a refrigerant, may flow from cylinder bore
5
to discharge chamber
19
. The refrigerant subsequently may be discharged from discharge chamber
19
to the external refrigerant circuit. Valve plate
20
also may comprise a discharge valve reed
22
formed on a side, e.g., the right side, of valve plate
20
. Specifically, discharge valve reed
22
is formed on the side opposite the side which suction valve reed
21
is formed. Discharge valve reed
22
regulates the fluid communication between cylinder bore
5
and discharge chamber
19
. Moreover, a valve retainer
30
formed on discharge valve reed
22
may limit the extent to which discharge valve reed
22
may bend when fluid flows from cylinder bore
5
to discharge chamber
19
.
Compressor
100
also may comprise an electromagnetic clutch
24
. When electromagnetic clutch
24
is activated, an external driving force from an external driving source (not shown) is transmitted to drive shaft
7
, such that drive shaft
7
, rotor
9
, and swash plate
6
rotate substantially simultaneously about the axis of drive shaft
7
. Moreover, wobble plate
14
moves back and forth in a wobbling motion without rotating about the axis of drive shaft
7
, such that only a direction of movement which is parallel to the axis of drive shaft
7
is transferred from wobble plate
14
to pistons
16
. Consequently, each piston
16
reciprocates within its corresponding cylinder bore
5
and compresses the fluid, e.g., the refrigerant, which flows into cylinder bore
5
from suction chamber
18
via suction hole
20
a.
The reciprocation of piston
16
may be divided into a suction stroke and a discharge stroke. Specifically, during the suction stroke, discharge hole
20
b
may be closed by discharge valve reed
22
, and during the discharge stroke, suction hole
20
a
may be closed by suction valve reed
21
. Referring to
FIGS. 2 and 3
, during the suction stroke, the fluid generally flows in the direction of limiting recess
23
′ as indicated by the arrow (L
1
). When the fluid approaches or reaches limiting recess
23
′, the fluid deflects off a portion of limiting recess
23
′ which intersects with center axis (X) and has a tangent line at the point of intersection which is substantially perpendicular to center axis (X) of suction valve reed
21
. As such, when the fluid approaches or reaches limiting recess
23
′, the direction of the flowing fluid changes by about 90° and the fluid flows in the directions indicated by the arrow (L
2
). Nevertheless, because the direction of the flowing fluid changes by about 90° when the fluid approaches or reaches limiting recess
23
′, the speed of the fluid decreases and the fluid may become stagnant within limiting recess
23
′. Consequently, during the suction stroke, the suction efficiency of the compressor may decrease.
SUMMARY OF THE INVENTION
Therefore, a need has arisen for refrigerant compressor which overcomes these and other shortcomings of the related art. A technical advantage of the present invention is that during the suction stroke, when a fluid approaches or reaches a limiting recess, the fluid may not become stagnant. Specifically, when the fluid approaches or reaches the limiting recess, the fluid may contact a portion of the limiting recess having a tangent line which forms an oblique angle relative to a center axis of a suction valve reed, i.e., an axis which is parallel to the direction of fluid flow. Consequently, when the fluid approaches or reaches the limiting recess, the fluid may deflect at an angle less than 90°, and the suction efficiency of the compressor may increase.
According to an embodiment of the present invention, a refrigerant compressor is described. The compressor
Baker & Botts L.L.P.
Sanden Corporation
Solak Timothy P.
Tyler Cheryl J.
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