Pumps – Condition responsive control of drive transmission or pump... – Adjustable cam or linkage
Reexamination Certificate
2001-06-20
2003-05-27
Walberg, Teresa (Department: 3742)
Pumps
Condition responsive control of drive transmission or pump...
Adjustable cam or linkage
C417S540000
Reexamination Certificate
active
06568914
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a swash plate type compressor used for the air conditioner of an automobile, and more particularly to a compressor with a pulsation pressure reducing structure, which is capable of reducing the noise of the pulsation pressure of refrigerant discharge in the process of refrigerant being compressed and discharged, thereby allowing the compressor to have a low operating noise.
2. Background of the Related Art
Generally, a compressor constituting a principal element of the cooling system of the air conditioner of an automobile is an apparatus that selectively receives power from an engine through a pulley by the intermittent action of an electromagnetic clutch, compresses vapor refrigerants having exchanged heat in an evaporator into high-temperature and high-pressure refrigerant easy to be liquefied, and discharges the resulting refrigerant to a condenser.
Such a compressor may be generally classified into a reciprocating type or rotary type according to its refrigerant compressing manner and refrigerant compressing structure.
The swash plate type compressor belonging to the reciprocating compressor is constructed to suck, compress and discharge low pressure refrigerant having been evaporated in an evaporator, in such a manner that a disc-shaped swash plate slantly mounted around a driving shaft to which the power of the engine is applied is rotated by means of the driving shaft and a plurality of pistons coupled by means of a shoe with the periphery of the swash plate are rectilinearly reciprocated through a plurality of bores formed on a cylinder. According to piston pressurizing manners, such the swash plate compressor may be classified into a single head piston type in which pressurizing force is applied to only the one face of the piston or duplex head piston type in pressurizing force is applied to the both faces of the piston.
The present invention relates to the single head piston type compressor, and more particularly to a variable displacement swash plate type compressor in which the inclination angle of its swash plate is varied, thereby making it possible to vary the amount of the reciprocating movement of the piston, such that the amount of compression of the refrigerants can be adjusted in accordance with thermal load.
The variable displacement swash plate type compressor has the following advantages when compared with a fixed displacement swash plate type compressor: that is, the variable displacement swash plate type compressor has a reduced number of parts, so it is lightweight and its refrigerant compressing capacity can be controlled depending on thermal load, thereby effectively adjusting a room temperature and improving the driving performance of an automobile.
FIG. 5
illustrates an example of a conventional variable displacement swash plate type compressor, wherein the internal construction thereof is shown.
As depicted in the drawing, the conventional variable displacement swash plate type compressor includes: a cylinder block
101
provided with a plurality of cylinder bores
103
in a longitudinal direction through the interior thereof; a front housing
111
positioned in front of the cylinder block
101
to define a crank chamber
113
in the interior thereof; a rear housing
121
coupled to the rear side of the cylinder block
101
to define a suction chamber
123
and a discharge chamber
125
in the interior thereof; a plurality of pistons
131
adapted to be inserted into each of the plurality of cylinder bores
103
of the cylinder block
101
to be moved forward and rearward and provided on their rear ends with a plurality of bridges
133
; a driving shaft
141
adapted to be inserted into the center of the cylinder block
101
through the front housing
111
and thus rotatably supported by the front housing
111
and the cylinder block
101
; a lug plate
151
adapted to be fixedly attached to the driving shaft
141
in the interior of the crank chamber
113
and thereby rotated with the driving shaft
114
; a swash plate
161
adapted to be fitted slantly to the driving shaft
141
in the crank chamber
113
in such a manner as to be adjusted in the inclination angle thereof, fitted through a shoe to a swash plate receiving groove of the bridge
133
on the rear end of each piston
131
on the outer periphery thereof and hinge-coupled rotatably to the lug plate
151
on the one side of the front surface thereof, thereby rotating with the lug plate
151
; and a valve plate
173
provided with a plurality of suction holes
175
a
and a plurality of discharge holes
175
b
for the plurality of cylinder bores
103
of the cylinder block
101
, between the cylinder block
101
and the rear housing
121
and disposed, with a suction reed valve
175
and a discharge reed valve
177
for opening and closing each of the suction holes
175
a
and discharge holes
175
b,
between the front and rear sides of the cylinder block
101
and the rear housing
121
, such that each bore
103
of the cylinder block
101
can be closed relative to the suction chamber
123
and the discharge chamber
125
of the rear housing
121
. A reference numeral
191
denotes a pressure control unit, which compares the pressure in the crank chamber
113
with the pressure in each bore
103
and controls the resulting pressure value, thereby varying the inclination angle of the swash plate
161
.
The compressor constructed as described above compresses refrigerant and discharges it to a condenser (not shown) while all the elements of the compressor operate in cooperation with one another.
First, when the driving shaft
141
selectively receives the rotary force of the pulley (not shown), to which the driving force of an engine is transmitted, by the intermittent action of the electromagnetic clutch (not shown) through a disc and hub assembly (not shown) and rotates, the lug plate
151
fixedly attached around the driving shaft
141
rotates together with the driving shaft
141
, resulting in the rotation of the swash plate
161
hinge-coupled to the lug plate
151
. At this time, the swash plate
161
is swung in an axial direction on the outer periphery thereof due to the inclination angle relative to the driving shaft
141
, such that each piston
131
engaged with the outer periphery of the swash plate
161
carries out a rectilinear reciprocating movement in an axial direction in each cylinder bore
103
. During this process, positive pressure and negative pressure are alternately produced in each bore
103
so that the refrigerant are sucked, compressed and discharged.
The conventional swash plate type compressor compressing refrigerant through the aforementioned process compresses the refrigerant by the rectilinear reciprocating movement of the pistons performed periodically at predetermined intervals, such that the flow of refrigerant has pulsation pressure having the same period as the refrigerant discharge period of each piston
131
while the refrigerant is discharged from each cylinder bore
103
through the discharge chamber
125
and the discharge hole
129
. As a result, the conventional swash plate type compressor is problematic in that a driving noise is caused by the pulsation pressure.
In order to solve the problem of the noise caused by the pulsation pressure, for example, in case of the duplex head piston type compressor where pressure is applied to the both faces of the piston, the pulsation pressure can be somewhat reduced in such a manner that the pulsation pressure of the compressed refrigerant discharged from the front housing is overlapped with the pulsation pressure of the compressed refrigerants discharged from the rear housing. However, in case of the single head piston type compressor where pressure is applied to only the one face of the piston, the single head piston type compressor cannot adopt the pulsation pressure reducing method of the duplex head piston compressor, in which two refrigerant flows discharged from two refrigerant discharge chambers
Fastovsky Leonid
Halla Climate Control Corp.
Lowe Hauptman & Gilman & Berner LLP
Walberg Teresa
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