Thermal expansion valve

Details Thermal expansion valve Thermal expansion valve

2002-04-08

2003-05-13

Doerrler, William C. (Department: 3744)

Refrigeration

Automatic control

Refrigeration producer

C236S09200D

Reexamination Certificate

active

06560982

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a thermal expansion valve equipped in a refrigeration system of an air conditioner for a vehicle and the like for controlling the flow of refrigerant being provided to an evaporator according to the temperature of the refrigerant.
DESCRIPTION OF THE RELATED ART
FIG. 3
is an explanatory view showing the vertical cross-section of the structure of a conventionally known thermal expansion valve.
A thermal expansion valve shown as a whole by reference number
1
comprises a square column shaped valve body
10
made of aluminum alloy and the like. The valve body
10
comprises a passage
20
for receiving a high-pressure refrigerant transmitted from a compressor of the air conditioner, and a valve chamber
22
formed to the lower portion of the valve body
10
that communicates with the passage
20
.
The valve chamber
22
communicates the passage
20
with a passage
26
via a valve seat
24
, and the refrigerant is sent out through the passage
26
toward an evaporator.
Within the valve chamber
22
is equipped a spherical valve means
30
that opposes against the valve seat
24
, and the valve means
30
is supported by a valve means support member
32
. The valve means support member
32
is supported via a spring
34
by a nut member
36
functioning as an adjustment screw. The nut member
36
is screwed onto the valve body
10
at a screw thread portion
37
by a tool such as a wrench and the like utilizing a hexagon hole
38
formed thereto.
By adjusting the depth of the nut member
36
being screwed onto the valve body, the spring force of the spring
34
supporting the valve means
30
can be controlled so that the valve means
30
is biased toward the direction closing the valve. A seal member
39
is fixed to the nut member
36
, thus preventing the refrigerant from leaking out of the valve chamber
22
.
The valve body
10
contains a return passage
28
of the refrigerant returning from the evaporator toward the compressor, formed in parallel with the passage
26
.
The valve means
30
is operated through a working rod
40
that penetrates the center portion of the valve body
10
. The working rod
40
is a small-diameter rod made of stainless steel and the like, the upper end thereof being inserted to a stopper member
50
and the lower end coming into contact with the valve means
30
.
A seal member
42
is equipped between the working rod
40
and the valve body
10
, which constitutes a seal between the passage
26
through which the refrigerant is sent out and the passage
28
through which the refrigerant returns.
The stopper member
50
is equipped within a driving device so-called a power element and shown as a whole by reference number
60
.
The power element
60
comprises a disc-shaped can body
62
defined by an upper lid
621
and a lower lid
622
, the can body
62
being screwed onto the upper portion of the valve body
10
via a screw thread
64
formed to the lower lid
622
, and the periphery of the stopper member
50
being supported by the lower lid
622
.
The can body
62
contains a diaphragm
66
, and the periphery of the diaphragm is sandwiched between the upper lid
621
and the lower lid
622
, which are fixed to each other by welding, defining an upper pressure chamber
68
and a lower pressure chamber
69
. A working fluid is filled within the upper pressure chamber
68
, and is sealed by a plug body
70
.
The pressure of the refrigerant passing through the return passage
28
of the refrigerant operates on the lower surface of the stopper member
50
, and the temperature of the refrigerant is transmitted via the working rod
40
to the stopper member
50
, and further transmitted via the diaphragm
66
to the working fluid within the upper pressure chamber
68
.
The diaphragm
66
is displaced by the pressure within the upper pressure chamber
68
, the amount of displacement thereof moving the valve means
30
through the working rod
40
, thus decompressing and expanding the refrigerant flowing through the passage
20
, adjusting the opening area of the orifice passage constituting the valve seat
24
, and controlling the flow of refrigerant traveling toward the evaporator.
In such conventional thermal expansion valve, the structure requires a large number of parts including the valve receiving member, the spring and the adjustment screw, making it difficult to reduce the size and the weight of the thermal expansion valve.
Moreover, a problem sometimes occurs according to the prior art valve in which the refrigerant leaks out of the valve chamber through the adjustment screw portion.
SUMMARY OF THE INVENTION
Considering these points, the object of the present invention is to provide a thermal expansion valve having a simplified structure and smaller number of parts being required, thus enabling to correspond to the desired reduction of size and weight of the car air conditioner.
In order to achieve the above objects, the present invention provides a thermal expansion valve comprising a valve body, a first passage formed to the valve body through which high pressure refrigerant travels, a valve chamber formed within the first passage, a second passage formed to the valve body in parallel with the first passage through which refrigerant traveling toward an evaporator travels, an orifice passage to which a valve seat member is press fit for communicating the valve chamber with the second passage, a valve means positioned opposing the orifice passage, a third passage through which refrigerant being sent out of the evaporator travels, and a temperature sensing rod for sensing the temperature of the refrigerant traveling through the third passage and driving the valve means according thereto; characterized in that the valve seat member is mounted between the working rod and the valve means in advance before it is fixed to the orifice passage, and the opening area of the orifice passage is adjusted by the displacement of the valve means.
Further, the above working rod comprises a small-diameter portion being inserted to the valve seat member, and having a spherical valve means fixed to the end of the small-diameter portion.
Moreover, the present valve is equipped with a spring that biases the working rod toward the diaphragm.


REFERENCES:
patent: 5597117 (1997-01-01), Watanabe et al.
patent: 5826438 (1998-10-01), Ohishi et al.
patent: 5943871 (1999-08-01), Ito et al.
patent: 5957376 (1999-09-01), Fujimoto et al.
patent: 5961038 (1999-10-01), Okada
patent: 6145753 (2000-11-01), Yano et al.
patent: 0 775 877 (1997-05-01), None

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