Pumps – Expansible chamber type – Having pumping chamber pressure responsive distributor
Reexamination Certificate
1999-02-04
2001-01-16
Walberg, Teresa (Department: 3742)
Pumps
Expansible chamber type
Having pumping chamber pressure responsive distributor
C417S269000, C417S571000, C137S856000
Reexamination Certificate
active
06174147
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a refrigerant compressor and, more specifically, to an improvement in a discharge valve and a retainer element assembly by which the physical durability of a discharge valve element of the refrigerant compressor may be surely improved.
2. Description of the Related Art
Many refrigerant compressors are known and one typical conventional compressor is a double-headed piston type swash-plate-operated refrigerant compressor as shown in FIG.
3
.
Referring to
FIG. 3
, the conventional refrigerant compressor includes a front cylinder block
80
and a rear cylinder block
81
which are disposed in an end-to-end relation to form a combined cylinder block. A plurality of cylinder bores
80
a
and
81
a
for forming compression chambers are formed in the front cylinder block
80
and the rear cylinder block
81
, respectively. Each pair of the cylinder bores
80
a
and
81
a
(a pair being one from each set of cylinder bores
80
a
and
81
a
) is coaxially aligned. A swash plate chamber
82
is formed in a middle part of the combined cylinder block. A front suction valve element
83
having a plurality of suction valves, a front valve plate
85
, a front discharge valve element
87
having a plurality of suction valve portions and, a front retainer element
89
are placed on the front end of the front cylinder block
80
. A rear suction valve element
84
having a plurality of suction valve portions, a rear valve plate
86
, a discharge valve element
88
having a plurality of discharge valve portions and a rear retainer element
90
are placed on the rear end of the rear cylinder block
81
. A front housing
91
and a rear housing
92
are joined to the front end of the front cylinder block
80
and the rear end of the rear cylinder block
81
, respectively, and these four elements are combined together with a plurality of through screw bolts
93
to form a housing assembly of the compressor. O-rings are arranged between the front cylinder block
80
and the rear cylinder block
81
, between the front cylinder block
80
and the front housing
91
, and between the rear cylinder block
81
and the rear housing
92
, respectively to hermetically seal the interior of the compressor against the external atmosphere. A drive shaft
94
is supported for rotation in the front housing
91
, the front cylinder block
80
and the rear cylinder block
81
via bearings housed in the front and rear cylinder blocks
80
and
81
. A swash plate
95
is mounted on the drive shaft
94
for rotation in the swash plate chamber
82
and is fixedly held in place on the drive shaft
94
by thrust bearings. A plurality of double-headed pistons
96
fitted in the cylinder bores
80
a
and
81
a
are linked to the swash plate
95
by shoes in contact with the front and the rear surface of the swash plate
95
, respectively.
The rear housing
92
has a suction chamber
92
a
capable of communicating with an external evaporator (not shown) via the swash plate chamber
82
, and a discharge chamber
92
b
capable of communicating with an external condenser (not shown). The suction chamber
92
a
and the discharge chamber
92
b
are defined by partition walls
92
c
and
92
d
. The rear valve plate
86
is provided with suction ports
86
a
connecting the suction chamber
92
a
and the cylinder bores
81
a
via the suction valves of the rear suction valve element
84
, and discharge ports
86
b
connecting the discharge chamber
92
b
and the cylinder bores
81
a
via the discharge valve portions of the rear discharge valve element
88
. The rear suction valve element
84
has a base portion held between the rear cylinder block
81
and the rear valve plate
86
, and the suction valve portions extending from the base portion and capable of being elastically moved to open the suction ports
86
a
into the suction chamber
92
a.
As shown in
FIG. 4
, the rear discharge valve element
88
has a base portion
88
a
held between the valve plate
86
and the rear housing
92
, and the valve portions
88
b
extending from the base portion
88
a
and capable of being elastically moved to open the discharge ports
86
b
into the discharge chamber
92
b
. The retainer element
90
has a base end portion
90
a
in contact with the base portion
88
a
of the rear valve element
88
and controlling portions
90
b
extend from the base end
90
a
to control the opening of the respective valve portions
88
b
of the rear valve element
88
. The respective controlling portions
90
b
are arranged to be in registration with the respective valve portions
88
b
of the rear valve element
88
and are curved into the interior of the discharge chamber
92
b
. The front and the rear surface of the retainer element
90
are coated with elastic layers (not shown) e.g., rubber layers or the like, so that the retainer element
90
may exhibit the function of gasket.
It should be noted that the front suction valve element
83
, the front valve plate
85
, the front discharge valve element
87
, the front retainer element
89
and, the front housing
91
on the front end of the front cylinder block
80
are basically constructed using the same design principle as that of the above-described respective elements, i.e., the rear suction valve element
84
, the rear valve plate
86
, the rear discharge valve element
88
, the rear retainer element
90
and the rear housing
92
.
When the drive shaft
94
of the compressor is driven to rotate, the swash plate
95
drives the double headed pistons
96
to reciprocate in the cylinder bores
80
a
and
81
a
. Consequently, for example, on the rear side, a low-pressure refrigerant gas is sucked into the cylinder bores
81
a
from the suction chambers
92
a
, via the suction ports
86
a
and the valve portions of the rear suction valve element
84
, and the refrigerant gas is compressed and discharged from the cylinder bores
81
a
into the discharge chamber
92
b
via the discharge port
86
b
, and the valve portions
88
b
of the rear discharge valve
88
. The refrigerant gas is sucked into and discharged from the cylinder bores
80
a
on the front side in the same way.
In the compressor incorporating the foregoing front and rear discharge valve elements and front and rear retainer elements therein, it has been recently found that the valve portions of the respective discharge valve elements are unsatisfactory in physical or mechanical durability. Namely, as shown in
FIG. 4
, in the conventional typical refrigerant compressor, for example, the partition wall
92
c
of the rear housing
92
has a holding portion
92
d
arranged to come into contact with the base portion
90
a
of the retainer element
90
when assembled, and a relieved portion
92
e
formed as a large cut recessed from a plane including the holding portion
92
d
in the extending direction of the valve parts
88
b
. In the compressor, the base end portion
90
a
of the rear retainer element
90
is pressed by the holding portion
92
d
of the rear housing
92
due to a clamping force exhibited by the through screw bolts
93
(
FIG. 2
) to fixedly hold the base portions
88
a
of the rear discharge valve element
88
and the base end portions
90
a
of the retainer element
90
between the valve plate
86
and the rear housing
92
.
In the described compressor, each relieved portion
92
e
is formed as a large cut recessed from a plane containing the holding portion
92
d
, and an edge
92
f
of the relieved portion
92
e
on the side of the valve portion
88
b
is spaced far from the back surface of the corresponding controlling portion
90
b
of the retainer element
90
. Therefore, a large amount of deformation of each controlling portion
90
b
of the retainer element
90
easily occurs in the discharge chamber
92
b
, to take the shape indicated by the alternate long and two short dashes lines. The deformation of the controlling portion
90
b
of the retainer element
90
is specifically generated when the compressor operates in a l
Deto Norikazu
Kuramoto Satoru
Shirai Kuniyoshi
Tarutani Tomoji
Fastovsky Leonid
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Walberg Teresa
Woodcock Washburn Kurtz Mackiewicz & Norris LLP
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