Pumps – Condition responsive control of drive transmission or pump... – Adjustable cam or linkage
Reexamination Certificate
1998-11-19
2001-04-17
Yuen, Henry C. (Department: 3747)
Pumps
Condition responsive control of drive transmission or pump...
Adjustable cam or linkage
C417S270000
Reexamination Certificate
active
06217290
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a control valve for a variable capacity compressor to be employed in air conditioners for vehicles, etc., and in particular to a control valve for a variable capacity compressor, which is designed to supply, upon requirements, a coolant gas from a discharge pressure region to a crankcase.
A variable capacity compressor provided with a cylinder, a piston, a wobble plate, etc. has been conventionally employed for compressing and discharging a coolant gas of an air conditioner for vehicles, etc. One example of this conventional variable capacity compressor is constructed such that it comprises a coolant gas passage for communicating a discharge pressure region with a crankcase, so that the quantity of coolant gas to be discharged can be changed in conformity with changes in inclination angle of the wobble plate which can be effected through an adjustment of the pressure inside the crankcase. The adjustment of pressure inside the crankcase is performed by feeding a high pressure compressed coolant gas from the discharge pressure region to the crankcase while adjusting the opening degree of a control valve disposed at an intermediate portion of the coolant gas passage.
FIGS. 6 and 7
show one example of such a control valve
100
′ for a variable capacity compressor (hereinafter referred to simply as a control valve) (see Japanese Patent Unexamined Publication (Kokai) H/9-268,974). This control valve
100
′ is disposed neighboring on the rear housing
210
of the variable capacity compressor
200
and is designed to adjust the pressure inside the crankcase
231
which is disposed in a front housing
230
and next to the a cylinder block
220
of the variable capacity compressor
200
.
In the interior of the crankcase
231
, there are housed a wobble plate
240
which is mounted on a driving shaft
250
in such a manner that it can slide along the axial direction of the driving shaft
250
and can incline about the driving shaft
250
, and also a guide pin
241
of the wobble plate
240
, which is made slidable along a supporting arm
252
of a rotatable supporting body
251
. The wobble plate
240
is connected via a couple of shoes
242
with a piston
260
which is slidably disposed in a cylinder bore
221
.
The wobble plate
240
is designed to swing in the directions indicated by the arrows so as to change its inclination angle in conformity with a difference in pressure between a suction pressure Ps inside the cylinder bore
221
and a pressure Pc inside the crankcase
231
. The stroke width of the forward and backward movement of the piston
260
in the cylinder bore
221
can be determined based on this inclination angle. Further, the inclinatory movement in the direction of arrows of the wobble plate
240
causes a cutoff body
270
contacting with a middle portion of the wobble plate
240
to move forward or backward in a housing bore
222
.
The rear housing
210
is provided with suction chambers
211
a
and
211
b
each constituting an inlet pressure region, and with discharging chambers
212
a
and
212
b
each constituting a discharge pressure region. When the piston
260
is moved forward and backward as a result of the inclinatory movement of the wobble plate
240
, the coolant gas in the suction chamber
211
a
is sucked into the cylinder bore
221
from a suction port
213
and then compressed to a predetermined pressure before it is discharged through a discharge port
214
into the discharging chamber
212
a.
An inlet passage
215
formed at the central portion of the rear housing
210
is communicated with the housing bore
222
and also with the suction chamber
211
b
through a through-hole
216
. When the wobble plate
240
is moved toward the cutoff body
270
, the cutoff body
270
is caused to move toward the inlet passage
215
thereby causing the through-hole
216
to be closed ultimately by the cutoff body
270
.
Between the inlet passage
215
and the upper end portion of the control valve
100
′, there is formed a pressure-checking passage
217
for introducing the suction pressure Ps into the control valve
100
′. The discharging chamber
212
b
is communicated with the crankcase
231
via gas inlet passages
218
and
219
of the control valve
100
′. These gas inlet passages
218
and
219
are designed to be opened or closed by means of a valve member
106
′ of the control valve
100
′. In this case, it is designed such that a discharging pressure Pd inside the discharging chamber
212
b
is allowed to be introduced via the gas inlet passage
218
to a valve chamber port
113
′, while the pressure Pc inside the crankcase
231
is allowed to be introduced via the gas inlet passage
219
to a valve chamber port
114
′. Further, it is also designed such that the suction pressure Ps is allowed to be introduced via the pressure-checking passage
217
into a sucking pressure-introducing port
115
′.
If a temperature detected by an indoor sensor
281
is higher than a set temperature of a temperature-setting device
282
at the moment when an actuating switch
280
of air conditioner is turned on, a controlling computer
283
outputs a command to magnetize the solenoid
101
′ of the control valve
100
′. As a result, an electric current is fed via an actuating circuit
284
to the solenoid
101
′ thereby causing the solenoid
101
′ to generate a suction force, due to which a movable core
102
′ is attracted, against the urging force (biasing force) of a spring
103
′, toward a fixed core
104
′.
As the movable core
102
′ is moved in this manner, the valve member
106
′ attached to a solenoid rod
105
′ is caused to move, against the urging force of a forced opening spring
107
′, in the direction to decrease the opening degree of a valve hole
108
′. As a result of this movement of the valve member
106
′, a pressure-sensitive rod
109
′ formed integral with the valve member
106
′ is moved upward thereby pushing up bellows
111
′ which is detachably connected with the pressure-sensitive rod
109
′ through a pressure-sensitive rod receiver
110
′.
At this moment, the displacement of bellows
111
′ is caused in conformity with changes of the suction pressure Ps to be introduced via the pressure-sensitive passage
217
into the interior of the pressure-sensitive chamber
112
′, thereby giving a load to the pressure-sensitive rod
109
′. Thus, the control valve
100
′ is designed such that the opening degree of the valve hole
108
′ by means of the valve member
106
′ is determined by a balance among the suction force of the solenoid
101
′, the urging force by the bellows
111
′ and the urging force by the forced opening spring
107
′.
If the cooling load is large in this case for instance, i.e. if a difference between the temperature detected by the indoor sensor
281
and the set temperature of the room temperature-setting device
282
is large, the suction force between the movable core
102
′ and the fixed core
104
′ is increased whereby increasing the force of the valve member
106
′ to bias the valve hole
108
′ in the direction to decrease the opening degree thereof, thus making it possible to perform the opening and closing of the valve member
106
′ with the lower suction pressure Ps.
When the opening degree of valve by means of the valve member
106
′ is decreased, the quantity of coolant gas to be fed to the crankcase
231
from the discharging chamber
212
b
via the gas inlet passages
218
and
219
is decreased, thus lowering the crankcase pressure Pc in the interior of the crankcase
231
.
Further, if the cooling load is large, the suction pressure Ps inside the cylinder bore
221
is increased whereby generating a difference in pressure between the suction pressure Ps inside the cylinder bore
221
and the crankcase pressur
Imai Masayuki
Kazahaya Yukio
Kume Yoshiyuki
Baker & Botts L.L.P.
Fujikoki Corporation
Gimie Mahmoud M
Yuen Henry C.
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