Thermal expansion valve

Details Thermal expansion valve Thermal expansion valve

2000-12-29

2002-08-06

Doerrler, William C. (Department: 3744)

Apparel

Body garments

Back and chest protectors

C062S225000

Reexamination Certificate

active

06427243

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a thermal expansion valve used in a refrigeration cycle.
DESCRIPTION OF THE RELATED ART
Heretofore, a thermal expansion valve used in the refrigeration cycle of an air conditioning device on a vehicle and the like comprised of a valve body including a high-pressure refrigerant passage through which liquid-phase refrigerant to be decompressed travels and a low-pressure refrigerant passage through which gas-phase refrigerant travels, and a valve hole formed to the high-pressure refrigerant passage; a valve means that is driven to move toward or away from the valve hole of the valve body for changing the opening of the valve hole; a pressure working housing mounted to the valve body for detecting the temperature of the gas-phase refrigerant, the housing equipped with a diaphragm for driving the valve means and controlling the movement thereof, and a pressure equalizing chamber communicated to the low-pressure refrigerant passage and an airtight chamber separated by the diaphragm and filled with a predetermined refrigerant; and a plug body for sealing the predetermined refrigerant filled into the airtight chamber through a hole formed to the outer wall of the pressure working housing.
This type of prior-art thermal expansion valve is shown in the vertical cross-sectional view of
FIG. 5
, which shows the state where the valve is equipped in a refrigeration cycle of the air conditioning device on a vehicle, the schematic outline view thereof shown in FIG.
6
. In
FIG. 5
, the thermal expansion valve
10
-
1
comprises a prism-shaped valve body
30
made for example of aluminum, and a first passage
32
through which refrigerant flowing in from a condenser
5
and a receiver
6
toward an evaporator
8
constituting the refrigeration cycle
11
travels, and a second passage
34
through which refrigerant flowing in from the evaporator
8
toward a compressor
4
travels, the first and second passages formed mutually separately with one passage placed above the other in the valve body. Moreover, the first passage
32
of the valve of
FIG. 5
is equipped with an orifice
32
a,
a valve chamber
35
, a spherical valve means
32
b
placed to the upper stream side of the passage
32
for controlling the quantity of refrigerant that passes through the orifice
32
a,
and an adjustment screw
39
of a spring
32
d
that presses the valve means
32
b
toward the orifice
32
a
through a valve member
32
c.
The adjustment screw
39
having a screw portion
39
f
is movably screwed onto a mounting hole
30
a
communicated to the valve chamber
35
of the first passage
32
through the lower end surface of the valve body
30
, with an o-ring mounted to the adjustment screw
39
that secures the airtight state with the valve body
30
. The adjustment screw
39
and the pressurizing spring
32
d
adjust the opening of the valve means
32
b
against the orifice
32
a.
Reference number
321
refers to an entrance port through which the refrigerant sent out from the receiver
6
toward the evaporator
8
enters. A valve chamber
35
is connected to the entrance port
321
, and reference number
322
refers to an exit port of the refrigerant flowing toward the evaporator
8
. In
FIG. 6
, reference number
50
refers to bolt holes for mounting the expansion valve to position, and the bottom region of the valve body
30
is formed narrower than the other regions. The valve body
30
is equipped with a small-diameter hole
37
and a large-diameter hole
38
having a larger diameter than the hole
37
, which open or close the orifice
32
a
by providing drive force to the valve means
32
corresponding to the exit temperature of the evaporator
8
of the valve body
30
, the holes
37
and
38
being formed in coaxial relations with the orifice
32
a.
The upper end of the valve body
30
is equipped with a screw hole
36
to which the power element unit
36
including an airtight chamber is fixed.
The power element unit
36
comprises a diaphragm
36
a
made for example of stainless steel, and an upper pressure working chamber
36
b
and a lower pressure working chamber
36
c
welded and sealed to each other with the diaphragm
36
a
sandwiched in between, forming two airtight chambers above and under the diaphragm. An upper lid
36
d
made of stainless steel defines the upper pressure working chamber
36
b
together with the diaphragm
36
a,
and is equipped with a hole
362
and a plug body
36
k
for sealing the predetermined refrigerant working as a diaphragm driving fluid in the upper chamber. The plug body
36
k
is made for example of stainless steel, which is formed either through cutting or forging, and welded onto the hole
362
of the upper lid
36
d
for securing an airtight chamber. The lower lid
36
h
is screwed onto the screw hole
361
through a packing
40
. The lower pressure working chamber
36
c
is communicated to the second passage
34
via a pressure equalizing hole
36
e
formed concentrically to the center line of the orifice
32
a.
The refrigerant exiting the evaporator
8
flows into the second passage
34
, and the passage
34
acts as the gas-phase refrigerant passage. The pressure of the refrigerant flowing through passage
34
is loaded to the lower pressure working chamber
36
c
via the pressure equalizing hole
36
e.
Further,
342
is the entrance port through which the refrigerant sent out from the evaporator
8
enters, and
341
is the exit port through which the refrigerant sent toward the compressor exits.
A heat sensing shaft
36
f
made of aluminum is equipped to the valve body, with a large-diameter dish shaped peak portion
312
formed to contact the center area of the lower surface of the diaphragm
36
a
within the lower pressure working chamber. The shaft
36
f
is slidably mounted inside the large-diameter hole
38
and penetrates through the second passage
34
, transmitting the refrigerant exit temperature of the evaporator
8
to the lower pressure working chamber
36
c,
and providing drive force by sliding inside the large-diameter hole
38
corresponding to the displacement of the diaphragm
36
a
accompanied by the pressure difference of the upper pressure working chamber
36
b
and the lower pressure working chamber
36
c.
Moreover, a working shaft
37
f
made of stainless steel and having a smaller diameter than the heat sensing shaft
36
f
is slidably mounted inside the small-diameter hole
37
for pressing the valve means
32
b
corresponding to the displacement of the heat sensing shaft
36
f
and resisting to the elastic force of the biasing means
32
d.
The upper end region of the heat sensing shaft
36
f
comprises a peak portion
312
that acts as the receiving portion of the diaphragm
36
a,
and a large-diameter portion
314
that slides within the lower pressure working chamber
36
c.
The lower end region of the heat sensing shaft
36
f
contacts the upper end region of the working shaft
37
f,
and the lower end region of the working shaft
37
f
contacts the valve means
32
b.
The heat sensing shaft
36
f
and the working shaft
37
f
constitute a valve driving shaft
318
. Further, the peak portion
312
and the large diameter portion
314
can be formed integrally.
As explained, the valve driving shaft
318
extending from the lower surface of the diaphragm
36
a
to the orifice
32
a
of the first passage
32
is concentrically arranged within the pressure equalizing hole
36
e.
The portion
37
e
of the working shaft
37
f
that penetrates the orifice
32
a
is formed narrower than the inner diameter of the orifice
32
a,
and the refrigerant travels through the orifice
32
a.
The heat sensing shaft
36
f
is equipped with an O-ring
36
g
that acts as a sealing member securing the seal between the first passage
32
and the second passage
34
.
A known diaphragm drive fluid is filled inside the upper pressure working chamber
36
b
of the pressure working housing
36
d.
The heat of the refrigerant flowing through the second passage
34
after exiting the evap

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