U.S. patent application number 17/435965 was filed with the patent office on 2022-05-12 for expansion valve.
The applicant listed for this patent is FUJIKOKI CORPORATION. Invention is credited to Masahiro TOMITSUKA, Takahiro YANO, Hiroshi YOKOTA.
Application Number | 20220146160 17/435965 |
Document ID | / |
Family ID | 1000006155069 |
Filed Date | 2022-05-12 |
United States Patent
Application |
20220146160 |
Kind Code |
A1 |
TOMITSUKA; Masahiro ; et
al. |
May 12, 2022 |
EXPANSION VALVE
Abstract
An improved expansion valve is provided, which has a simple
configuration and with which noise can be reduced. An expansion
valve includes a valve main body having a valve chamber and a valve
seat, a valve body configured to prevent passage of a fluid by
being seated on the valve seat and allow passage of the fluid by
separating from the valve seat, a coil spring configured to urge
the valve body toward the valve seat, and an actuation rod
configured to press the valve body toward a direction separating
from the valve seat against an urging force applied from the coil
spring, wherein the valve chamber includes a cylindrical inner wall
being connected to the valve seat, the valve body includes a
contact portion configured to be seated on the valve seat and a
body portion having a tubular shape facing the inner wall, and the
body portion includes connecting surfaces that are slidably in
contact with the inner wall and plane surfaces that have a gap
provided between the inner wall.
Inventors: |
TOMITSUKA; Masahiro; (Tokyo,
JP) ; YOKOTA; Hiroshi; (Tokyo, JP) ; YANO;
Takahiro; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJIKOKI CORPORATION |
Tokyo |
|
JP |
|
|
Family ID: |
1000006155069 |
Appl. No.: |
17/435965 |
Filed: |
February 10, 2020 |
PCT Filed: |
February 10, 2020 |
PCT NO: |
PCT/JP2020/005113 |
371 Date: |
September 2, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25B 41/31 20210101;
F25B 2500/12 20130101 |
International
Class: |
F25B 41/31 20060101
F25B041/31 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 15, 2019 |
JP |
2019-048420 |
Claims
1. An expansion valve comprising: a valve main body comprising a
valve chamber and a valve seat; a valve body configured to limit
passage of a fluid by being seated on the valve seat and allow
passage of the fluid by separating from the valve seat; a coil
spring configured to urge the valve body toward the valve seat; and
an actuation rod configured to press the valve body toward a
direction separating from the valve seat against an urging force
applied from the coil spring, wherein the valve chamber comprises a
cylindrical inner wall being connected to the valve seat, the valve
body comprises a contact portion configured to be seated on the
valve seat and a body portion having a tubular shape facing the
inner wall, in a cross section taken in a direction orthogonal to
an axis of the valve body, a shape of an inner circumference of the
inner wall differs from a shape of an outer circumference of the
body portion, so that a space through which the fluid passes is
formed between the inner wall and the body portion, and the inner
circumference of the inner wall and the outer circumference of the
body portion are partially slidably in contact with each other,
bubbles in the fluid are collapsed when the fluid passes through
the space formed between the inner wall and the body portion, and
the fluid passes the valve seat after passing through the space
formed between the inner wall and the body portion.
2. The expansion valve according to claim 1, wherein the inner wall
comprises a cylindrical shape, and the body portion comprises a
polygonal tubular shape.
3. The expansion valve according to claim 1, wherein the inner wall
comprises a polygonal tubular shape, and the body portion comprises
a cylindrical shape.
4. The expansion valve according to claim 1, wherein the inner wall
comprises a cylindrical shape, and the body portion comprises a
non-round cross section.
5. The expansion valve according claim 1, wherein the actuation rod
and the valve body are abutted against each other in a relative
displaceable manner.
Description
TECHNICAL FIELD
[0001] The present invention relates to an expansion valve.
BACKGROUND ART
[0002] Hitherto, in a refrigeration cycle system adopted in an air
conditioner mounted on an automobile, for example, a
temperature-sensitive expansion valve that adjusts an amount of a
refrigerant passing therethrough according to temperature, with the
aim to cut down installation space and piping.
[0003] In a general expansion valve, a spherical valve body
arranged in a valve chamber is positioned to face a valve seat
formed as an opening on the valve chamber. The valve body is
supported by a valve body support arranged in the valve chamber and
urged toward the valve seat by a coil spring arranged between a
spring holding member attached to the valve main body and the valve
body support. Then, the valve body is pressed by an actuation rod
driven by a power element and moves away from the valve seat to
allow passage of a refrigerant. The refrigerant that has passed
through a throttle flow channel between the valve seat and the
valve body is sent through an outlet port toward an evaporator.
[0004] At an initial timing when the refrigeration cycle system is
started, a liquid density of the refrigerant passing through the
throttle flow channel between the valve seat and the valve body is
low, and a flow speed of the refrigerant increases as the flow
resistance reduces. Therefore, a large friction noise tends to
occur at a valve portion at the start of the refrigeration cycle
system, and therefore, limiting of flow rate of the refrigerant is
required as a countermeasure. Meanwhile, during a stable period in
which a certain time has elapsed from the activation of the
refrigeration cycle, friction noise becomes small since the liquid
density becomes higher compared to when the refrigeration cycle is
started. The flow rate during the stable period should not be
limited excessively, and rather, there is a contradictory request
of a need to ensure a sufficient refrigerant flow rate.
[0005] Patent Literature 1 discloses an expansion valve that
defines a refrigerant inlet of the valve chamber and a gap between
the valve body support and the valve chamber so as to realize a
good balance between reduction of friction noise of the refrigerant
when starting the refrigeration cycle system and ensuring a
necessary flow rate of the refrigerant passing through the throttle
flow channel.
CITATION LIST
Patent Literature
[0006] [PTL 1] Publication of Japanese Patent No. 5369259
SUMMARY OF INVENTION
Technical Problem
[0007] Meanwhile, noise caused by the refrigerant other than the
friction noise is also generated in the expansion valve. For
example, according to the expansion valve disclosed in Patent
Literature 1, bubbles in the refrigerant may reach the valve seat
without being collapsed and may burst simultaneously when the
refrigerant passes through the valve seat, which may be recognized
as noise.
[0008] Therefore, the present invention aims at providing an
improved expansion valve having a simple configuration and with
which noise can be reduced.
Solution to Problem
[0009] In order to achieve the above object, the expansion valve
according to the present invention includes:
[0010] a valve main body including a valve chamber and a valve
seat;
[0011] a valve body configured to prevent passage of a fluid by
being seated on the valve seat and allow passage of the fluid by
separating from the valve seat;
[0012] a coil spring configured to urge the valve body toward the
valve seat; and
[0013] an actuation rod configured to press the valve body toward a
direction separating from the valve seat against an urging force
applied from the coil spring,
[0014] wherein the valve chamber includes a cylindrical inner wall
being connected to the valve seat,
[0015] the valve body includes a contact portion configured to be
seated on the valve seat and a body portion having a tubular shape
facing the inner wall, and
[0016] in a cross section taken in a direction orthogonal to an
axis of the valve body, a shape of an inner circumference of the
inner wall differs from a shape of an outer circumference of the
body portion, so that a space through which the fluid passes is
formed between the inner wall and the body portion, and the inner
circumference of the inner wall and the outer circumference of the
body portion are partially slidably in contact with each other.
Advantageous Effects of Invention
[0017] The present invention provides an improved expansion valve
having a simple configuration and with which noise can be
reduced.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 is a schematic cross-sectional view illustrating an
example where an expansion valve according to a first embodiment is
applied to a refrigerant cycle system.
[0019] FIG. 2 is a top view of a cross section taken at line A-A of
FIG. 1.
[0020] FIG. 3 is a perspective view of a valve body according to
the present embodiment.
[0021] FIG. 4 is a cross-sectional view illustrating a vicinity of
a valve body of an expansion valve according to a second embodiment
in enlarged view.
[0022] FIG. 5 is a top view of a cross section taken at line B-B of
FIG. 4.
[0023] FIG. 6 is a perspective view of the valve body according to
the present embodiment.
[0024] FIG. 7 is a cross-sectional view illustrating a vicinity of
a valve body of an expansion valve according to a third embodiment
in enlarged view.
[0025] FIG. 8 is a top view of a cross section taken at line C-C of
FIG. 7.
[0026] FIG. 9 is a perspective view of the valve body according to
the present embodiment.
[0027] FIG. 10 is a cross-sectional view of a body portion
according to a modified example.
DESCRIPTION OF EMBODIMENTS
Definition
[0028] In the present specification, a direction from a valve body
3 toward an actuation rod 5 is defined as an "upper direction", and
a direction from the actuation rod 5 toward the valve body 3 is
defined as a "lower direction". Therefore, according to the present
specification, the direction from the valve body 3 toward the
actuation rod 5 is referred to as the "upper direction" regardless
of the orientation of an expansion valve 10.
[0029] In the present specification, a "polygonal tubular shape"
refers to a tubular shape having a outer circumference that
surrounds an axis with four or more plane surfaces. However, if
there are connecting surfaces that connect the plane surfaces, such
connecting surfaces are not included in the plane surfaces.
Further, "the shape of the inner circumference being different from
the shape of the outer circumference in cross section" means that
the shape of the inner circumference is neither the same as nor
similar to the shape of the outer circumference.
First Embodiment
[0030] A general configuration of the expansion valve 10 according
to a first embodiment will be described with reference to FIG. 1.
FIG. 1 is a schematic cross-sectional view illustrating an example
where the expansion valve 10 according to the present embodiment is
applied to a refrigerant cycle system 100. In the present
embodiment, the expansion valve 10 is connected to a compressor
101, a capacitor 102 and an evaporator 104 that constitute the
refrigerant cycle system 100.
[0031] The expansion valve 10 includes a valve main body 2 equipped
with a cylindrical valve chamber VS, the valve body 3, an urging
device 4, the actuation rod 5, and a ring spring 6.
[0032] The valve main body 2 includes a first flow channel 21 and a
second flow channel 22 in addition to a valve chamber VS. The first
flow channel 21 is a supply-side flow channel, for example, and a
refrigerant, also referred to as a fluid, is supplied to the valve
chamber VS via a supply-side flow channel. The second flow channel
22 is a discharge-side flow channel, for example, and the fluid in
the valve chamber VS is discharged via an orifice portion 27 and
the second flow channel 22 to the exterior of the expansion valve.
The first flow channel 21 and the valve chamber VS are connected
via a connection path 21a having a smaller diameter than the first
flow channel 21.
[0033] The valve chamber VS includes a valve seat 20 which is an
inner circumference of a lower edge of the orifice portion 27
having a cylindrical shape, and a cylindrical inner wall 24
connected to the valve seat 20 and having a greater diameter than
the valve seat 20.
[0034] FIG. 2 is a top view of a cross section taken at line A-A of
FIG. 1, and it illustrates a cross section of the valve body 3 in a
direction orthogonal to the axis. FIG. 3 is a perspective view of
the valve body 3. In FIG. 3, the valve body 3 is formed by
consecutively connecting a conical contact portion 31, a body
portion 32 having a hexagonal tubular shape, a flange portion 33
having a disk shape, and an end portion 34 having a cylindrical
shape.
[0035] A tapered surface 31b of the contact portion 31 is abutted
against the valve seat 20. An upper surface 31a of the contact
portion 31 is a plane surface that is orthogonal to an axis L. An
outer circumference of the body portion 32 is composed of six plane
surfaces 32a and connecting surfaces 32b that are formed between
adjacent plane surfaces 32a. Each connecting surface 32b can either
be a plane surface or a curved surface, and the peripheral length
is preferably 1/4 or less of the peripheral length of the plane
surface 32a. Further, the axial-direction length of the body
portion 32 is preferably the same size as an inner diameter of an
inner wall 24 of the valve chamber VS (or a maximum diagonal length
of the body portion 32) or greater.
[0036] The valve body 3 is arranged in the valve chamber VS. In the
cross section of FIG. 2, a shape of an inner circumference of the
inner wall 24 of the valve chamber VS and a shape of an outer
circumference of the body portion 32 differ, and according to an
eccentricity of the valve chamber VS and the valve body 3, one of
the connecting surfaces 32b abut and slide against the inner wall
24 of the valve chamber VS. Meanwhile, regardless of the
eccentricity of the valve chamber VS and the valve body 3, the
inner wall 24 of the valve chamber VS does not abut against the
plane surfaces 32a. Therefore, the refrigerant will pass through
the space formed between the inner wall 24 and the plane surfaces
32a.
[0037] In FIG. 1, in a state where the valve body 3 is seated on
the valve seat 20 having an annular shape arranged in the valve
main body 2, the first flow channel 21 and the second flow channel
22 are in a non-communicated state. Meanwhile, in a state where the
valve body 3 is separated from the valve seat 20, the first flow
channel 21 and the second flow channel 22 are in a communicated
state. However, there may be a case where a limited amount of
refrigerant is allowed to pass through even when the valve body 3
is seated on the valve seat 20.
[0038] A lower end of the actuation rod 5 inserted to an actuation
rod inserting hole 28 of the valve main body 2 and also inserted to
the orifice portion 27 with a gap therebetween is in contact with
the upper surface 31a of the valve body 3 in a manner relatively
displaceable in a direction intersecting the axis L. Further, the
actuation rod 5 can press the valve body 3 toward a valve opening
direction against an urging force applied from the urging device 4.
In a state where the actuation rod 5 moves in the lower direction,
the valve body 3 separates from the valve seat 20 and the expansion
valve 10 will be in an opened state.
[0039] Next, a power element 8 for driving the actuation rod 5 will
be described. In FIG. 1, the power element 8 is attached to a
recessed portion 2a provided on a top portion of the valve main
body 2. The recessed portion 2a is communicated via a communication
path 2b with a return flow channel 23 within the valve main body 2
through which the refrigerant from the evaporator 104 passes. The
actuation rod 5 is passed through the communication path 2b. A
female screw is formed on an inner circumference of the recessed
portion 2a.
[0040] The power element 8 includes a plug 81, an upper lid member
82, a diaphragm 83, a stopper member 84, and a receiver member
86.
[0041] The upper lid member 82 includes a conical portion 82a
arranged at a center and a flange portion 82b having an annular
shape and extending from a lower end of the conical portion 82a
toward the outer circumference. An opening 82c is formed at a top
portion of the conical portion 82a, which can be sealed by the plug
81.
[0042] The diaphragm 83 is formed of a thin plate material on which
a plurality of corrugated shapes of concentric circles are formed,
and it has an outer diameter that is approximately the same as an
outer diameter of the flange portion 82b.
[0043] The stopper member 84 includes a fitting hole 84a formed at
a center of a lower end thereof.
[0044] The receiver member 86 includes a flange portion 86a having
an outer diameter that is approximately the same as the outer
diameter of the flange portion 82b of the upper lid member 82, a
stepped portion 86c having an annular support surface 86b that is
substantially orthogonal to the axis L, and a hollow cylindrical
portion 86b. A male screw is formed on an outer circumference of
the hollow cylindrical portion 86b.
[0045] A process for assembling the power element 8 will be
described. The upper lid member 82, the diaphragm 83, the stopper
member 84 and the receiver member 86 are arranged so that they are
in a positional relationship as illustrated in FIG. 1.
[0046] Further, in a state where the outer circumference portions
of the flange portion 82b of the upper lid member 82, the diaphragm
83 and the flange portion 86a of the receiver member 86 are
superposed, the outer circumference portions are subjected to girth
welding by TIG welding, laser welding or plasma welding, for
example, and integrated.
[0047] Next, after filling a space (pressure operation chamber PO)
surrounded by the upper lid member 82 and the diaphragm 83 with
operative gas through the opening 82c formed on the upper lid
member 82, the opening 82c is sealed by the plug 81, and
thereafter, the plug 81 is fixed to the upper lid member 82 by
projection welding, for example.
[0048] In this state, the diaphragm 83 receives pressure from the
operative gas filled in the pressure operation chamber PO in a
direction pressing the diaphragm 83 toward the receiver member 86,
so that the diaphragm 83 abuts against and is supported by an upper
surface of the stopper member 84 arranged in a space (pressure
detection chamber PD) surrounded by the diaphragm 83 and the
receiver member 86.
[0049] During assembly of the power element 8, in a state where an
upper end of the actuation rod 5 is fit to the fitting hole 84a of
the stopper member 84, the male screw on the hollow cylindrical
portion 86b of the receiver member 86 is screwed to the female
screw on the recessed portion 2a of the valve main body 2 that is
communicated with the return flow channel 23, and the power element
8 is thereby fixed to the valve main body 2.
[0050] In this state, a packing PK is interposed between the power
element 8 and the valve main body 2 so as to prevent leakage of the
refrigerant from the recessed portion 2a when the power element 8
is attached to the valve main body 2. In this state, the pressure
detection chamber PD of the power element 8 is communicated with
the return flow channel 23.
[0051] The ring spring 6 is a vibration absorption member that
suppresses the vibration of the actuation rod 5. The ring spring 6
is arranged in an annular portion 26 adjacent to the actuation rod
inserting hole 28 of the valve main body 2 and applies a
predetermined elastic force to an outer circumference surface of
the actuation rod 5 by a claw portion protruded to an inner
circumference direction.
[0052] The urging device 4 includes a coil spring 41 formed by
winding a round wire helically, and a spring holding member 43. The
spring holding member 43 has a function to seal the opening of the
valve chamber VS of the valve main body 2 and also has a function
to support a lower end of the coil spring 41. An O-ring 44 is
arranged between the spring holding member 43 and the inner wall of
the valve chamber VS to prevent leakage of the refrigerant.
[0053] The valve body 3 illustrated in FIG. 3 is retained by having
an upper end of the coil spring 41 abut against a lower side of the
flange portion 33 and also having the end portion 34 fit to an
inner side of the upper end of the coil spring 41
(Operation of Expansion Valve)
[0054] An operation example of the expansion valve 10 will be
described with reference to FIG. 1. The refrigerant pressurized by
the compressor 101 is liquefied in the capacitor 102 and sent to
the expansion valve 10. Further, the refrigerant subjected to
adiabatic expansion in the expansion valve 10 is sent to the
evaporator 104, and in the evaporator 104, the refrigerant is
subjected to heat exchange with the air flowing in a circumference
of the evaporator. The refrigerant returning from the evaporator
104 is returned through the expansion valve 10 (more specifically,
the return flow channel 23) toward the compressor 101.
[0055] A high-pressure refrigerant is supplied to the expansion
valve 10 from the capacitor 102. More specifically, the
high-pressure refrigerant from the capacitor 102 is supplied via
the first flow channel 21 to the valve chamber VS.
[0056] In a state where the contact portion 31 of the valve body 3
is seated on the valve seat 20 (in other words, when the expansion
valve 10 is in the closed state), the first flow channel 21
upstream of the valve chamber VS and the second flow channel 22
downstream of the valve chamber VS are in a non-communicated state.
Meanwhile, in a state where the contact portion 31 of the valve
body 3 is separated from the valve seat 20 (in other words, when
the expansion valve 10 is in the opened state), the refrigerant
supplied to the valve chamber VS is sent through the orifice
portion 27 and the second flow channel 22 toward the evaporator
104.
[0057] According to the present embodiment, in a state where the
contact portion 31 of the valve body 3 is separated from the valve
seat 20, the refrigerant containing bubbles in the valve chamber VS
is guided along the axial length of the body portion 32 through a
relatively narrow gap between the plane surfaces 32a of the body
portion 32 of the valve body 3 and the inner wall 24, during which
time the bubbles are gradually collapsed. Therefore, the bubbles
will not collapse simultaneously when the refrigerant passes
through the valve seat 20, so that the energy generated by the
bursting of the bubbles is reduced and the noise generated during
passage of the refrigerant is cut down. Further, by having the
refrigerant flow along the plane surfaces 32a along the axial
length of the body portion 32, a flow straightening effect of the
refrigerant is achieved.
[0058] Switching of the closed state and the opened state of the
expansion valve 10 is carried out by the actuation rod 5 connected
to the power element 8. In this state, the connecting surfaces 32b
of the body portion 32 sliding against the inner wall 24 has a long
length corresponding to the axial length of the body portion 32, so
that tilting that may be caused when the contact portion 31 of the
valve body 3 separates from the valve seat 20 can be suppressed.
Thus, further to the upper surface 31a being relatively
displaceable with respect to the actuation rod 5, smooth movement
of the valve body 3 can be ensured.
[0059] In FIG. 1, the pressure operation chamber PO and the
pressure detection chamber PD that are separated by the diaphragm
83 are provided inside the power element 8. Therefore, when the
operative gas within the pressure operation chamber PO is
liquefied, the actuation rod 5 moves to the upper direction, and
when the liquefied operative gas is gasified, the actuation rod 5
moves to the lower direction. Thus, the switching between the
valve-opened state and the valve-closed state of the expansion
valve 10 is carried out.
[0060] Further, the pressure detection chamber PD of the power
element 8 is communicated with the return flow channel 23.
Therefore, the pressure of the refrigerant flowing through the
return flow channel 23 is transmitted via the stopper member 84 and
the diaphragm 83 to the operative gas inside the pressure operation
chamber PO. Thereby, the volume of the operative gas inside the
pressure operation chamber PO is changed, and the actuation rod 5
is driven. In other words, according to the expansion valve 10
illustrated in FIG. 1, the amount of the refrigerant supplied from
the expansion valve 10 to the evaporator 104 is automatically
adjusted according to the pressure of the refrigerant returning
from the evaporator 104 to the expansion valve 10.
Second Embodiment
[0061] Next, an expansion valve according to a second embodiment
will be described. FIG. 4 is a cross-sectional view illustrating a
vicinity of a valve body of an expansion valve 10A in enlarged
view. FIG. 5 is a top view of a cross section taken at line B-B of
FIG. 4. FIG. 6 is a perspective view of the valve body 3A.
[0062] In FIG. 6, the valve body 3A is formed by consecutively
connecting a conical contact portion 31A, a body portion 32A having
a hexagonal tubular shape, and an end portion 34A having a
cylindrical shape.
[0063] A tapered surface 31Ab of the contact portion 31A is abutted
against the valve seat 20. Further, an upper surface 31Aa of the
contact portion 31A is a plane surface that is orthogonal to the
axis L. An outer circumference of the body portion 32A is composed
of six plane surfaces 32Aa and connecting surfaces 32Ab that are
formed between adjacent plane surfaces 32a. Each connecting surface
32b can either be a plane surface or a curved surface. The
peripheral length of the body portion 32A is preferably the same
size as a diameter of an inner wall 24A of the valve chamber VS (or
a maximum diagonal length of the body portion 32) or greater. The
connecting surfaces 32Ab constitute a sliding contact portion, and
the plane surfaces 32Aa constitute a flow channel portion.
[0064] An inner wall 24A of the valve chamber VS is formed greater
than an outer diameter of the coil spring 41. The other
configurations are similar to the above-described embodiment, so
the similar components are denoted with the same reference numbers
and detailed descriptions thereof are omitted.
[0065] According to the present embodiment, in a state where the
contact portion 31A of the valve body 3A is separated from the
valve seat 20, the refrigerant containing bubbles in the valve
chamber VS is guided along the axial length of the body portion 32A
through a relatively narrow gap between the plane surfaces 32Aa of
the body portion 32A of the valve body 3A and the inner wall 24A,
during which time the bubbles are gradually collapsed. Therefore,
the bubbles will not collapse simultaneously when the refrigerant
passes through the valve seat 20, so that the energy generated by
the bursting of the bubbles is reduced and the noise generated
during passage of the refrigerant is cut down. Further, by having
the refrigerant flow along the plane surfaces 32Aa along the axial
length of the body portion 32A, a flow straightening effect of the
refrigerant is achieved.
[0066] Since the connecting surfaces 32Ab of the body portion 32A
that abut against the inner wall 24A during opening and closing of
the valve have a long length corresponding to the axial length of
the body portion 32A, tilting caused when the contact portion 31A
of the valve body 3A separates from the valve seat 20 can be
suppressed. Thus, further to the upper surface 31Aa being
relatively displaceable with respect to the actuation rod 5, smooth
movement of the valve body 3 can be ensured.
[0067] Especially since the position in which the connecting
surfaces 32Ab abut against the inner wall 24A is relatively distant
from the axis L, tilting of the valve body 3A can be suppressed
effectively.
Third Embodiment
[0068] Next, an expansion valve according to a third embodiment
will be described. FIG. 7 is a cross-sectional view illustrating a
vicinity of a valve body of an expansion valve 10B in enlarged
view. FIG. 8 is a top view of the cross section taken at line C-C
of FIG. 7. FIG. 9 is a perspective view of a valve body 3B.
[0069] In FIG. 9, the valve body 3B is formed by consecutively
connecting a conical contact portion 31B, a body portion 32B having
a cylindrical shape, a flange portion 33B having a disk shape, and
an end portion 34B having a cylindrical shape.
[0070] A tapered surface 31Bb of the contact portion 31B is abutted
against the valve seat 20. Further, an upper surface 31Ba of the
contact portion 31B is a plane surface that is orthogonal to the
axis L. The length of the body portion 32B should preferably be the
same as a maximum diagonal length of an inner wall 24B of the valve
chamber VS (or a diameter of the body portion 32B) or greater.
[0071] As illustrated in FIG. 8, the inner wall 24B of the valve
chamber VS has a hexagonal tubular shape formed of six plane
surfaces 24Bb. The outer circumference of the body portion 32B of
the valve body 3B is in contact with the plane surfaces 24Bb at any
of the six contact points CP illustrated in FIG. 8. Therefore, the
contact point CP at the outer circumference surface of the body
portion 32B constitutes a sliding contact portion, and the outer
circumference surface between adjacent contact points CP
constitutes a flow channel portion. The other configurations are
similar to the embodiment described above, so they are denoted with
the same reference numbers and detailed descriptions thereof are
omitted.
[0072] According to the present embodiment, in a state where the
contact portion 31B of the valve body 3B is separated from the
valve seat 20, the refrigerant containing bubbles in the valve
chamber VS is guided along the axial length of the body portion 32B
through a relatively narrow gap between the outer circumference
surface of the body portion 32B of the valve body 3B and the inner
wall 24B, during which time the bubbles are gradually collapsed.
Therefore, the bubbles will not collapse simultaneously when the
refrigerant passes through the valve seat 20, so that the energy
generated by the bursting of the bubbles is reduced and the noise
generated during passage of the refrigerant is cut down. Further,
by having the refrigerant flow along the plane surfaces 24Bb along
the axial length of the body portion 32B, a flow straightening
effect of the refrigerant is achieved.
[0073] Since the plane surfaces 24Bb that abut against the body
portion 32B have a long length corresponding to the axial direction
of the valve body 3B, tilting caused when the contact portion 31B
of the valve body 3B separates from the valve seat 20 can be
suppressed. Thus, further to the upper surface 31Ba being
relatively displaceable with respect to the actuation rod 5, smooth
movement of the valve body 3B can be ensured.
Modified Example
[0074] FIG. 10 is a view similar to FIG. 2 illustrating a cross
section of a valve body and an inner wall of a valve chamber
according to a modified example. In the present modified example,
an inner wall 24D of a valve chamber at a valve main body 2D is a
cylindrical surface, whereas a body portion 32D of the valve body
has a non-round cross section. Specifically, the body portion 32D
is formed of a partially cylindrical surface 32Da and a plane
surface 32Db. The width of the plane surface 32Db is shorter than a
diameter of the partially cylindrical surface 32Da. A
cross-sectional shape of the body portion 32D is the same
throughout the whole length of the body portion 32D. The partially
cylindrical surface 32Da constitutes the sliding contact portion,
and the plane surface 32Db constitutes the flow channel portion.
The other configurations are similar to the embodiments described
earlier, so they are denoted with the same reference numbers, and
detailed descriptions thereof are omitted.
[0075] According to the present modified example, in a state where
the valve body is separated from the valve seat, the refrigerant
containing bubbles in the valve chamber is guided along the axial
length of the body portion 32D through a relatively narrow gap
between the plane surface 32Db of the body portion 32D of the valve
body and the inner wall 24D, during which time the bubbles are
gradually collapsed. Therefore, the bubbles will not collapse
simultaneously when the refrigerant passes through the valve seat,
so that the energy generated by the bursting of the bubbles is
reduced and the noise generated during passage of the refrigerant
is cut down. Further, by having the refrigerant flow along the
plane surface 32Db along the axial length of the body portion 32D,
a flow straightening effect of the refrigerant is achieved.
[0076] The present invention is not limited to the above-described
embodiments. Arbitrary components of the above-described
embodiments can be modified within the scope of the present
invention. Further, arbitrary components can be added to or omitted
from the above-described embodiments. For example, the flow channel
portion is not limited to being a plane surface, and it can be a
protruded curved surface or a recessed curved surface.
REFERENCE SIGNS LIST
[0077] 10, 10A, 10B: expansion valve [0078] 2, 2A, 2B 2D: valve
main body [0079] 3, 3A, 3B: valve body [0080] 4: urging device
[0081] 5: actuation rod [0082] 6: ring spring [0083] 8: power
element [0084] 20: valve seat [0085] 21: first flow channel [0086]
22: second flow channel [0087] 23: return flow channel [0088] 26:
annular portion [0089] 27: orifice portion [0090] 41: coil spring
[0091] 42: valve body support [0092] 43: spring holding member
[0093] 100: refrigerant cycle system [0094] 101: compressor [0095]
102: capacitor [0096] 104: evaporator [0097] VS: valve chamber
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