U.S. patent application number 09/750117 was filed with the patent office on 2001-07-26 for thermal expansion valve.
This patent application is currently assigned to Fujikoki Corporation. Invention is credited to Kato, Asao, Kobayashi, Kazuto.
Application Number | 20010009099 09/750117 |
Document ID | / |
Family ID | 18537164 |
Filed Date | 2001-07-26 |
United States Patent
Application |
20010009099 |
Kind Code |
A1 |
Kobayashi, Kazuto ; et
al. |
July 26, 2001 |
Thermal expansion valve
Abstract
A thermal expansion valve 10-3 includes a passage 32 through
which refrigerant enters a prism-shaped body 30 from a receiver,
and a valve means 32b placed within a valve chamber 35 for
controlling the opening of an orifice 32a. The refrigerant
returning from an evaporator 8 travels through a passage 34 toward
a compressor 4. A power element 60 that drives the valve means 32b
via a heat sensing shaft 36f comprises a disk-shaped housing 36d
and a diaphragm 60a placed within said housing, which constitute a
pressure working chamber 36b. A working gas is filled inside said
pressure working chamber 36b and sealed thereto by a plug body 60k.
The diameter size of the diaphragm 60a and the whole size of the
plug body 60k are reduced in order to miniaturize and reduce the
weight of the thermal expansion valve as a whole.
Inventors: |
Kobayashi, Kazuto; (Tokyo,
JP) ; Kato, Asao; (Tokyo, JP) |
Correspondence
Address: |
Monica Millner
RADER, FISHMAN & GRAUER
The Lion Building
1233 20th Street, N.W., Suite 501
Washington
DC
20036
US
|
Assignee: |
Fujikoki Corporation
|
Family ID: |
18537164 |
Appl. No.: |
09/750117 |
Filed: |
December 29, 2000 |
Current U.S.
Class: |
62/204 ;
62/210 |
Current CPC
Class: |
F25B 41/335 20210101;
F16K 31/002 20130101; F25B 2500/32 20130101; F25B 2341/0683
20130101; F25B 2500/17 20130101 |
Class at
Publication: |
62/204 ;
62/210 |
International
Class: |
F25B 041/04; F25B
041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 18, 2000 |
JP |
2000-008956 |
Claims
We claim:
1. A thermal expansion valve comprising: a valve means that changes
the opening of a valve hole and controls the quantity of flow of
refrigerant flowing into an evaporator in a refrigeration cycle;
and a power element unit equipped with a plug body that seals a
predetermined refrigerant in an airtight chamber defined by a
diaphragm that controls the movement of said valve means; wherein
the diameter D.sub.1 of the peak portion of said plug body ranges
between 2 mm.ltoreq.D.sub.1<5.4 mm.
2. A thermal expansion valve according to claim 1, wherein the
diameter of said diaphragm ranged from 34.5 to 35.5 mm.
3. A thermal expansion valve comprising: 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 said high-pressure refrigerant passage;
a valve means that is driven to move toward or away from said valve
hole of said valve body for changing the opening of said valve
hole; a power element unit including a diaphragm that drives said
valve means and controls the movement thereof, and an airtight
chamber defined by said diaphragm, said power element unit mounted
to said valve body for detecting the temperature of said
refrigerant traveling through said low-pressure refrigerant
passage; and a plug body that seals the refrigerant filled into
said chamber through a hole formed to the outer wall of said power
element unit; wherein said plug body is welded onto the peripheral
area of said hole, the diameter D.sub.1 of the peak portion of said
plug body ranging between 2 mm.ltoreq.D.sub.1<5.4 mm, and the
diameter of said diaphragm ranging from 34.5 to 35.5 mm.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a thermal expansion valve
used in a refrigeration cycle.
DESCRIPTION OF THE RELATED ART
[0002] 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.
[0003] 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 32a, a valve chamber 35, a
spherical valve means 32b placed to the upper stream side of the
passage 32 for controlling the quantity of refrigerant that passes
through the orifice 32a, and an adjustment screw 39 of a spring 32d
that presses the valve means 32b toward the orifice 32a through a
valve member 32c. The adjustment screw 39 having a screw portion
39f is movably screwed onto a mounting hole 30a 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 32d
adjust the opening of the valve means 32b against the orifice
32a.
[0004] 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 32a 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 32a. 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.
[0005] The power element unit 36 comprises a diaphragm 36a made for
example of stainless steel, and an upper pressure working chamber
36b and a lower pressure working chamber 36c welded and sealed to
each other with the diaphragm 36a sandwiched in between, forming
two airtight chambers above and under the diaphragm. An upper lid
36d made of stainless steel defines the upper pressure working
chamber 36b together with the diaphragm 36a, and is equipped with a
hole 362 and a plug body 36k for sealing the predetermined
refrigerant working as a diaphragm driving fluid in the upper
chamber. The plug body 36k 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 36d for securing an airtight chamber.
The lower lid 36h is screwed onto the screw hole 361 through a
packing 40. The lower pressure working chamber 36c is communicated
to the second passage 34 via a pressure equalizing hole 36e formed
concentrically to the center line of the orifice 32a. 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 36c via the pressure
equalizing hole 36e. 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.
[0006] A heat sensing shaft 36f 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 36a within the lower pressure working chamber. The shaft
36f 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 36c, and providing drive force by sliding
inside the large-diameter hole 38 corresponding to the displacement
of the diaphragm 36a accompanied by the pressure difference of the
upper pressure working chamber 36b and the lower pressure working
chamber 36c. Moreover, a working shaft 37f made of stainless steel
and having a smaller diameter than the heat sensing shaft 36f is
slidably mounted inside the small-diameter hole 37 for pressing the
valve means 32b corresponding to the displacement of the heat
sensing shaft 36f and resisting to the elastic force of the biasing
means 32d. The upper end region of the heat sensing shaft 36f
comprises a peak portion 312 that acts as the receiving portion of
the diaphragm 36a, and a large-diameter portion 314 that slides
within the lower pressure working chamber 36c. The lower end region
of the heat sensing shaft 36f contacts the upper end region of the
working shaft 37f, and the lower end region of the working shaft
37f contacts the valve means 32b. The heat sensing shaft 36f and
the working shaft 37f constitute a valve driving shaft 318.
Further, the peak portion 312 and the large diameter portion 314
can be formed integrally.
[0007] As explained, the valve driving shaft 318 extending from the
lower surface of the diaphragm 36a to the orifice 32a of the first
passage 32 is concentrically arranged within the pressure
equalizing hole 36e. The portion 37e of the working shaft 37f that
penetrates the orifice 32a is formed narrower than the inner
diameter of the orifice 32a, and the refrigerant travels through
the orifice 32a. The heat sensing shaft 36f is equipped with an
O-ring 36g that acts as a sealing member securing the seal between
the first passage 32 and the second passage 34.
[0008] A known diaphragm drive fluid is filled inside the upper
pressure working chamber 36b of the pressure working housing 36d.
The heat of the refrigerant flowing through the second passage 34
after exiting the evaporator 8 is transmitted to the diaphragm
drive fluid via the valve drive shaft 318 exposed to the second
passage 34 or the pressure equalizing hole 36e communicated to the
second passage 34, and via the diaphragm 36a.
[0009] The diaphragm drive fluid filled inside the upper pressure
chamber 36b gasifies corresponding to the transmitted heat, and
loads pressure onto the upper surface of the diaphragm 36a. The
diaphragm 36a is displaced in the vertical direction corresponding
to the difference in the pressure of the diaphragm drive gas loaded
to the upper surface thereof and the pressure loaded to the lower
surface thereof.
[0010] The vertical displacement of the center area of the
diaphragm 36a is transmitted via the valve drive shaft to the valve
means 32b, thereby moving the valve means 32b closer to or away
from the valve seat of the orifice 32a. As a result, the flow of
the refrigerant is controlled.
[0011] The temperature of the low-pressure gas-phase refrigerant at
the exit side of the evaporator 8 (being sent out from the
evaporator) is transmitted to the upper pressure working chamber
36b, and corresponding to the transmitted temperature, the pressure
in the upper pressure working chamber 36b changes, and the exit
temperature of the evaporator 8 rises. In other words, when the
heat load of the evaporator increases, the pressure of the upper
pressure working chamber 86b rises, and correspondingly, the heat
sensing shaft 36f or valve drive shaft is driven downward pressing
down the valve means 32b, thereby increasing the opening of the
orifice 32a. This increases the amount of refrigerant being
supplied to the evaporator 8, and reduces the temperature of the
evaporator 8. In contrast, the temperature of the refrigerant
exiting the evaporator 8 is reduced. In other words, if the heat
load of the evaporator is reduced, the valve means 32b is driven to
the opposite direction, reducing the opening of the orifice 32a,
reducing the amount of refrigerant supplied to the evaporator, and
thereby increases the temperature of the evaporator 8.
[0012] According to the thermal expansion valve shown in FIG. 5,
the heat sensing shaft 36f is a member having a relatively large
diameter, and this member together with a working shaft constitute
the valve drive shaft. However, another prior art example of the
thermal expansion valve includes a valve drive shaft formed of a
rod member. The thermal expansion valve 10-2 according to the prior
art using this rod member is shown in FIG. 7. The movement of the
thermal expansion valve shown in FIG. 7 is similar to the thermal
expansion valve shown in FIG. 5, and the members provided with the
same reference numbers as used in FIGS. 5 and 6 refer to either
identical or equivalent parts. Further, the components constituting
the refrigeration cycle, such as the compressor, the condenser, the
receiver and the evaporator, are not shown in FIG. 7.
[0013] The heat sensing portion 318 equipped with a heat sensing
structure works as the heat sensing shaft 361f, and a diaphragm 36a
contacts the surface thereof. The heat sensing portion 318 includes
a large-diameter stopper portion 312 that receives the diaphragm
36a, a large-diameter portion 314 having one end surface attached
to the back surface of the stopper portion 312 and the center area
of the other end surface formed into a protrusion 315 that is
slidably inserted to the lower pressure working chamber 36c, and an
integrally-formed continuous rod member 316 having one end surface
fit into the protrusion 315 formed to the large-diameter portion
314 and the other end surface attached to a valve means 32b via a
portion 371f corresponding to the working shaft. The heat sensing
shaft 361f constituting the rod member 316 is exposed to the second
passage, and the heat of the refrigerant vapor is transmitted
therethrough.
[0014] The rod member 316 working as the heat sensing shaft 361f is
driven to move back and forth traversing the passage 34 along with
the displacement of the diaphragm 36a in the power element unit 36.
With this movement, a clearance (gap) communicating the passage 32
and the passage 34 is formed along the rod portion 316. In order to
prevent such communication, an O-ring 42 is mounted in a
large-diameter hole 38' that contacts the outer circumference of
the rod portion 316, and thereby, the O-ring is placed between the
two passages. Moreover, a push nut 41 working as a detent nut is
fixed to the rod portion 316 inside the large-diameter hole 38' and
adjacent to the O-ring 42, preventing the O-ring from moving by the
force working in the longitudinal direction (the direction toward
the power element portion 36) provided by the refrigerant pressure
of the passage 321 and the coil spring 32d.
[0015] The plug body 36k of the conventional thermal expansion
valve and the welding of the plug body 36k and the hole 362 is
disclosed for example in Japanese Patent Laid-Open Publications No.
6-185833 and No. 8-226567.
SUMMARY OF THE INVENTION
[0016] This type of thermal expansion valve is used to constitute a
part of the refrigeration cycle of an air conditioning device on a
vehicle, and is either placed inside the engine room with the
compressor, the evaporator, the receiver and the like, or inside
the passenger room with the evaporator. Therefore, the size of the
valve must be reduced as much as possible.
[0017] However, according to the conventional thermal expansion
valve, the size of the power element unit was the problem in trying
to miniaturize the thermal expansion valve. That is, as shown in
the cross-sectional drawing of FIG. 8, the plug body 36k of the
power element unit 36 of the conventional thermal expansion valve
is formed so that the diameter d.sub.1 at the peak portion
36k.sub.1 is set in the range of 5.4-5.5 mm, the diameter d.sub.2
at the bottom portion 36k.sub.2 is set in the range of 1.5-1.6 mm,
and the height h from the bottom portion 36k.sub.2 to the peak
portion 36k.sub.1 is set in the range of 4.7-4.8 mm. Moreover, the
diameter d.sub.3 of the diaphragm 36a of the power element unit 36
is set to 39 mm, as shown in the cross-sectional view of FIG. 9
together with the upper lid 36d. The size of the power element unit
was not considered according to the conventional thermal expansion
valve.
[0018] Therefore, the present invention aims at miniaturizing the
plug body included in the power element unit of a thermal expansion
valve, and to further provide a miniaturized thermal expansion
valve realized by the miniaturization of the plug body. Moreover,
the present invention realizes, without having to change the
structure of the thermal expansion valve, the miniaturization of
the plug body leading to the miniaturization of the thermal
expansion valve as a whole enabled by the miniaturization of the
diaphragm.
[0019] In order to achieve the above objects, the present invention
provides a thermal expansion valve comprising a valve means that
changes the opening of a valve hole and controls the quantity of
flow of refrigerant flowing into an evaporator in a refrigeration
cycle, and a power element unit equipped with a plug body that
seals a predetermined refrigerant in an airtight chamber defined by
a diaphragm that controls the movement of the valve means, wherein
the diameter D.sub.1 of the peak portion of the plug body is within
the range of 2 mm.ltoreq.D.sub.1<5.- 4 mm.
[0020] According to another feature of the thermal expansion valve
of the present invention, the diameter of the diaphragm
constituting the power element unit is within the range of
34.5-35.5 mm.
[0021] In yet another aspect of the present invention, the thermal
expansion valve comprises 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 power element unit
including a diaphragm that drives the valve means and controls the
movement thereof, and an airtight chamber defined by the diaphragm,
the power element unit mounted to the valve body for detecting the
temperature of the refrigerant traveling through the low-pressure
refrigerant passage, and a plug body that seals the refrigerant
filled into the chamber through a hole formed to the outer wall of
the power element unit, wherein the plug body is welded onto the
peripheral area of the hole, the diameter D.sub.1 of the peak
portion of the plug body being within the range of 2
mm.ltoreq.D.sub.1<5.4 mm, and the diameter of the diaphragm
being within the range of 34.5-35.5 mm.
[0022] The thermal expansion valve according to the present
invention equipped with a power element unit, including a plug body
formed into a specific shape as disclosed above, contributes to
reducing the size of the diaphragm and the size of the power
element unit, and thereby realizes miniaturization of the thermal
expansion valve as a whole.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a vertical cross-sectional view showing one
embodiment of the thermal expansion valve according to the present
invention;
[0024] FIG. 2 is a cross-sectional view showing the shape of the
plug body used in FIG. 1;
[0025] FIG. 3 is a cross-sectional view showing the shape of the
diaphragm used in FIG. 1;
[0026] FIG. 4 is a vertical cross-sectional view showing another
embodiment of the thermal expansion valve according to the present
invention;
[0027] FIG. 5 is a vertical cross-sectional view showing the
structure of a conventional thermal expansion valve;
[0028] FIG. 6 is a perspective view showing the outline of the
thermal expansion valve of FIG. 5;
[0029] FIG. 7 is a vertical cross-sectional view showing the
structure of another conventional thermal expansion valve;
[0030] FIG. 8 is a cross-sectional view showing the shape of the
plug body used in the conventional thermal expansion valve; and
[0031] FIG. 9 is a cross-sectional view showing the shape of the
diaphragm used in the conventional thermal expansion valve.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0032] The embodiment of the present invention will now be
explained with reference to the drawings.
[0033] FIG. 1 is a vertical cross-sectional view showing one
embodiment of a thermal expansion valve 10-3 according to the
present invention. The present valve 10-3 is formed similarly as
the thermal expansion valve 10-1 shown in FIG. 5 except that in the
present valve, a small-sized plug body 60k is used instead of the
plug body 36k constituting the power element unit 36. Moreover, the
structure of the present valve 10-3 is identical to the structure
of the thermal expansion valve 10-1 of FIG. 5, except that since
the present valve utilizes a small-sized plug body 60k, the size of
the diaphragm 60a is reduced, and as a result, the power element
unit 60 is miniaturized. The plug body 60k is formed for example by
forging. Accordingly, in the present explanation of the embodiment
of FIG. 1, the same components that act similarly as the components
of the thermal expansion valve 10-1 of FIG. 5 are provided with the
same reference numbers, and the explanations thereof are omitted.
The cross-sectional shape of the plug body 60k of the thermal
expansion valve 10-3 is as shown in FIG. 2. In the present
embodiment, the diameter D.sub.1 of the peak portion 60k.sub.1 is
in the range of 2 mm.ltoreq.D.sub.1<5.4 mm, the diameter D.sub.2
of the bottom portion 60k.sub.2 is in the range of 0.5
mm.ltoreq.D.sub.2<1.5 mm, and the height H from the peak portion
60k.sub.1 to the bottom portion 60k.sub.2 is in the range of 1.5
mm.ltoreq.H<4.7 mm. According to the best mode for carrying out
the embodiment, D.sub.1 should be in the range of 2.9
mm.ltoreq.D.sub.1<3.1 mm, D.sub.2 should be in the range of 1.1
mm.ltoreq.D.sub.2<1.3 mm, and H.sub.2 should be in the range of
2.2 mm.ltoreq.H.sub.2<2.4 mm.
[0034] The shape of the plug body 60k of the thermal expansion
valve 10-3 according to the present invention is determined in
consideration of the miniaturization limit related to the
processing of the plug body 60k and the automated plug supply, and
the welding strength to be provided when the plug body is welded
through projection welding and the like to the hole 362 formed to
the upper lid 36d of the power element unit 60. Since the diameter
d.sub.1 of the peak 36k.sub.1 of the plug body 36k shown in FIG. 8
in the thermal expansion valve 10-1 of FIG. 5 is set to 5.4-5.5 mm,
and since the diameter D.sub.1 of the peak portion k.sub.1 of the
present plug body 60k is in the range of 2 mm.ltoreq.D.sub.1<5.4
mm, the size of the plug body 60k in the power element unit 60 of
the present thermal expansion valve 10-3 is reduced. This will
enable the size of the power element unit 60 to be reduced, and
thus realizes the miniaturization of the thermal expansion valve
10-3 as a whole. Similarly, the diameter D.sub.2 of the bottom
portion 60k.sub.2 of the plug body 60k is in the range of 0.5
mm.ltoreq.D.sub.2<1.5 mm, and the height H of the plug body 60k
is in the range of 1.5 mm.ltoreq.H<4.7 mm.
[0035] Moreover, the diaphragm 60a of the power element unit 60 has
a cross-sectional shape as shown with an upper lid 36d in FIG. 3,
wherein further to using a small plug body 60k, the diameter
D.sub.3 of the diaphragm 60a is reduced to the range of 34.5-35.5
mm. Accordingly, the diaphragm of the present embodiment is
miniaturized compared to the conventional diaphragm 36a of the
power element unit 36 having a diameter d.sub.3 of 39 mm.
[0036] FIG. 4 is a vertical cross-sectional view showing another
embodiment of the thermal expansion valve 10-4 of the present
invention. The present valve 10-4 is similar to the thermal
expansion valve 10-2 shown in FIG. 7, except that a small-sized
plug body 60k is utilized instead of the plug body 36k constituting
the power element unit 36. The only structural difference of the
present valve 10-4 compared to the structure of the valve 10-2 of
FIG. 7 is that the diaphragm 60a is miniaturized, and as a result,
the power element unit 60 as a whole is miniaturized by the use of
the small plug body 60k. Accordingly, in the present explanation of
the embodiment of FIG. 4, the components that are equivalent to and
act similarly as the components in the thermal expansion valve 10-2
of FIG. 7 are provided with the same reference numbers, and the
explanations thereof are omitted. Moreover, the small-sized plug
body 60k and the diaphragm 60a utilized in the embodiment of FIG. 4
are the same as those shown in FIG. 2 and FIG. 3.
[0037] The embodiments of the thermal expansion valve according to
the present invention are shown in FIG. 1 and FIG. 4. However, the
present invention is not limited to the two embodiments shown
above, but can also be applied to a thermal expansion valve where
the valve body is driven by a power element unit that includes a
diaphragm defining an airtight chamber filled with a predetermined
refrigerant and sealed using a plug body.
[0038] The thermal expansion valve according to the present
invention can be miniaturized as a whole by the use of a plug body
having a specific form. Moreover, the miniaturization of the
diaphragm leads to the miniaturization of the power element unit,
and the present invention contributes to realizing a thermal
expansion valve having a reduced size, by providing a miniaturized
power element unit without changing the other conventional
structural members.
* * * * *