Valves and valve actuation – Fluid actuated or retarded – Fluid and non-fluid actuators
Reexamination Certificate
2000-12-28
2002-07-09
Derakshani, Philippe (Department: 3754)
Valves and valve actuation
Fluid actuated or retarded
Fluid and non-fluid actuators
C251S058000, C251S061000, C251S208000, C251S229000, C251S264000
Reexamination Certificate
active
06416032
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is related to an expansion valve of an air conditioning system in an automobile and more particularly, to an expansion valve of an air conditioning system in an automobile which can control linearly a flow of a refrigerant by using holes of a fixed hole plate fixed to a valve body and a rotatable cam, which is rotated by a vertical movement of a pin in response to a pressure resulted from the difference in an outlet pressure of an evaporator and inside pressure of a pressure proof barrel, without employing a conventional opening and shutting method by means of a motion of a pin and ball.
2. Information Disclosure Statement
In general, an air conditioning system for an automobile is an apparatus to lower an ambient temperature by using a principle of the refrigeration cycle with supplying cold air.
The air conditioning system for the automobile comprises four main members of an evaporator, a compressor, a condenser and an expansion valve.
The expansion valve in such air conditioning system for an automobile controls a flow rate of the refrigerant at an exit of an evaporator by supplying the refrigerant in a state of a wet steam of low pressure into the evaporator receives a liquid refrigerant of high pressure and throttles the liquid refrigerant to be evaporated easily and then supplies. A controlling of a flow rate of the refrigerant flow into the evaporator is performed so that a pressure in an inlet of the evaporator is controlled.
FIG. 4
is a sectional view showing an expansion valve of a conventional air conditioning system for an automobile. As shown in
FIG. 4
, a cylindrical valve body
10
in which a refrigerant flow passage is formed consists of an inlet
12
, an inlet
14
of the evaporator, an outlet
16
of the evaporator, a mounting portion
19
formed at an upper portion for mounting a pressure proof barrel body
20
, an orifice
18
for communicating the inlet
12
with the inlet
14
of the evaporator, and a pressure controlling portion
17
formed at a lower portion.
The inlet
12
through which a refrigerant of high pressure is flow into the expansion valve is formed at a side of a lower portion of the expansion valve.
The inlet
14
of the evaporator through which the refrigerant of high pressure flow from the inlet
12
is flow into the evaporator is formed at other side of an upper portion adjacent to the inlet
12
. The outlet
16
of the evaporator penetrates the upper portion of the expansion valve to supply the refrigerant in state of a vapor heated in the evaporator to the compressor. The pressure controlling portion
17
controls an opening and shutting state of the orifice
18
selectively to control a flowing pressure applied to the outlet
16
of the evaporator.
A pressure proof barrel body
20
consisted of a pressure proof barrel
24
sealed by a metal diaphragm
22
with a predetermined pressure at an upper portion is mounted to the mounting portion
19
.
A pin
30
is received in the valve body
10
in longitudinal direction and moved upward and downward according to the movement of the metal diaphragm
22
to which an upper end of the pin is fixed. A pin guide
32
formed at an upper end of the pin
30
is slid in the pressure proof barrel body
20
according to the flowing pressure from the evaporator, a lower end of the pin
30
is slid in the orifice
18
.
A seal member
34
is installed to a mid portion of the pin
30
for dividing into the outlet
16
and the inlet
14
of the evaporator, a ball
35
is attached to the lower end of the pin
30
for opening and shutting the orifice
18
. The ball
35
is supported elastically by a coil spring
37
and a ball base
36
fixed to an upper end of the coil spring
37
, a screw
38
for adjusting a tension of the coil spring
37
is mounted to a lower portion of the coil spring
37
so that a pressure of the outlet
16
of the evaporator is controlled.
Hereinafter, an operating state of the conventional expansion valve will be described as follows.
In
FIG. 4
, the metal diaphragm
22
pushes the pin
30
downward along the orifice
18
according to a pressure difference between the outlet
16
of the evaporator and the interior of the pressure proof barrel
24
so that the ball
35
attached to the pin
30
is moved downward to open the orifice
18
and the flow passage through which the refrigerant can be flow into the evaporator is opened.
In the conventional expansion valve, a pressure of the outlet
16
of the evaporator is controlled by the flow rate of the refrigerant which is passed through the orifice
18
and the screw
38
for adjusting a tension of the coil spring
37
, the controlled pressure of the outlet
16
of the evaporator controls the flow rate of the refrigerant which is passed along the orifice
18
by a means for opening and shutting a flow passage of the refrigerant.
In the conventional expansion valve, however, the ball is vibrated is by the flow of the refrigerant since the means for opening and shutting a flow passage of the refrigerant is consisted of the unfixed ball, a noise is caused by this.
Also, when the orifice is opened, it is impossible to adjust the flow rate exactly and linearly according to a vertical stroke of the pin so that an inflow amount of the refrigerant is increased suddenly by the ball, thus a temperature in the evaporator is changed suddenly. In addition, an excessive refrigerant is flow into the evaporator so that a huntting phenomenon occurs, that is, the expansion valve reduces the inflow amount of the refrigerant again.
Also, a vertical movement of the pin is controlled according to a pressure difference between the outlet of the evaporator and the interior of the pressure proof barrel, however, a setting pressure of the interior of the pressure proof barrel may be changed during the process of the mass production so that a heavy expense and time for managing the tolerance is consumed. Moreover, if the above problem becomes deeper, a liquid refrigerant is flow into the compressor so that a durability of the compressor is weakened.
Therefore, the present invention is invented to solve the problems as described, an object of the present invention is to provide an expansion valve of an air conditioning system for an automobile which does not employ a conventional opening and shutting method by means of a motion of a pin and ball and can control a flow of a refrigerant and control linearly a flow rate of a refrigerant flow into an evaporator by using holes of a fixed hole plate fixed to a valve body and holes of a rotatable cam which is rotated by a vertical stroke of a pin moved in response to a pressure difference between an outlet of an evaporator of an expansion valve and an interior of a pressure proof barrel, whereby it is possible to prevent a huntting phenomenon, a reverse flow of the refrigerant into the evaporator and a noise caused by a ball, which have been generated in a conventional expansion valve, from creating.
SUMMARY OF THE INVENTION
An expansion valve of an air conditioning system for an automobile of the present invention has a valve body in which a refrigerant flow passage is formed, a pressure proof barrel body comprising a pressure proof barrel sealed with a predetermined pressure by a metal diaphragm, and a device for opening or shutting the refrigerant flow passage in the expansion valve. The expansion valve of the present invention also comprises a pin having a upper end at which a pin guide having a vertical guide groove is formed, an upper surface with which a lower surface of the metal diaphragm is contacted and a lower portion on which a screw portion is formed; a rotatable cam combined with the screw portion of the pin; a fixed hole plate located at a lower portion of the rotatable cam and fixed to the valve body; a refrigerant wall dividing an inlet and an outlet of the evaporator and having a seal member mounted on an inner circumference through which the pin is passed, whereby a mid portion of the pin can be slid therein; a first spr
Bonderer D. Austin
Derakshani Philippe
Hyundai Motor Co.
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