U.S. patent application number 12/516621 was filed with the patent office on 2010-03-18 for control valve for variable displacement compressor.
This patent application is currently assigned to Calsonic Kansei Corporation. Invention is credited to Takashi Kobayashi, Koichi Shimada.
Application Number | 20100068074 12/516621 |
Document ID | / |
Family ID | 39467921 |
Filed Date | 2010-03-18 |
United States Patent
Application |
20100068074 |
Kind Code |
A1 |
Shimada; Koichi ; et
al. |
March 18, 2010 |
CONTROL VALVE FOR VARIABLE DISPLACEMENT COMPRESSOR
Abstract
A control valve is configured such that as a position of a high
pressure-side valve body positioned by a solenoid is closer to one
side, a degree of opening for communication of a high pressure
valve portion is more widened and a pressure on the side of a
discharge flow path acting on the high pressure-side valve body is
weakened. Further, the control valve is configured such that as a
position of a low pressure-side valve body positioned by the
solenoid is closer to the other side, a degree of opening for
communication of a low pressure valve portion is more widened. When
the high pressure-side valve body and the low pressure-side valve
body are integrally positioned on the one side by the solenoid and
the low pressure-side valve body is positioned on the other side by
the solenoid, the high pressure-side valve body and the low
pressure-side valve body are separated from each other.
Inventors: |
Shimada; Koichi; (Munich,
DE) ; Kobayashi; Takashi; (Tokyo, JP) |
Correspondence
Address: |
FOLEY AND LARDNER LLP;SUITE 500
3000 K STREET NW
WASHINGTON
DC
20007
US
|
Assignee: |
Calsonic Kansei Corporation
|
Family ID: |
39467921 |
Appl. No.: |
12/516621 |
Filed: |
November 29, 2007 |
PCT Filed: |
November 29, 2007 |
PCT NO: |
PCT/JP2007/073104 |
371 Date: |
May 28, 2009 |
Current U.S.
Class: |
417/222.1 |
Current CPC
Class: |
F04B 2027/1854 20130101;
F04B 2027/1827 20130101; F04B 27/1804 20130101; F04B 2027/1831
20130101 |
Class at
Publication: |
417/222.1 |
International
Class: |
F04B 49/22 20060101
F04B049/22 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 30, 2006 |
JP |
2006-323428 |
Claims
1. A control valve for a variable displacement compressor
comprising a high pressure valve portion provided in an
introducing-side communication passage which brings a discharge
flow path and a control pressure chamber of the variable
displacement compressor into communication with each other, and a
low pressure valve portion provided in a discharging-side
communication passage which brings an intake flow path and the
control pressure chamber into communication with each other, in
which degree of opening for communication of the high pressure
valve portion and the low pressure valve portion are variably
controlled, thereby varying a pressure in the control pressure
chamber to change an angle of a swash plate, wherein the control
valve further comprises a position control unit which controls
advancing/retracting positions of a high pressure-side valve body
of the high pressure valve portion and a low pressure-side valve
body of the low pressure valve portion, as a position of the high
pressure-side valve body positioned by the position control unit is
closer to one side, a degree of opening for communication of the
high pressure valve portion is more widened, a pressure on the side
of a discharge flow path acting on the high pressure-side valve
body is weakened, as a position of the low pressure-side valve body
positioned by the position control unit is closer to the other
side, a degree of opening for communication of the low pressure
valve portion is more widened, and when the high pressure-side
valve body and the low pressure-side valve body are integrally
positioned on the one side by the position control unit and the low
pressure-side valve body is positioned on the other side by the
position control unit, the high pressure-side valve body and the
low pressure-side valve body are separated from each other.
2. The control valve for a variable displacement compressor
according to claim 1, wherein when the high pressure-side valve
body and the low pressure-side valve body are positioned on the one
side by the position control unit, the low pressure valve portion
is fully closed.
3. The control valve for a variable displacement compressor
according to claim 1, further comprising an urging unit which
urges, of the high pressure-side valve body and the low
pressure-side valve body, only the low pressure-side valve body
toward the other side.
Description
TECHNICAL FIELD
[0001] The present invention relates to a control valve for a
variable displacement compressor.
BACKGROUND ART
[0002] As a conventional control valve for a variable displacement
compressor used for a refrigeration cycle of an automotive air
conditioning system, there has been known a control valve including
a high pressure valve portion provided in an introducing-side
communication passage which brings a discharge flow path and a
control pressure chamber of the variable displacement compressor
into communication with each other, and a low pressure valve
portion provided in a discharging-side communication passage which
brings an intake flow path and the control pressure chamber, in
which a degree of opening for communication between the high
pressure valve portion and the low pressure valve portion is
variably controlled, thereby changing a pressure in the control
pressure chamber to change an angle of a swash plate.
[0003] According to such a configuration, a case chamber (crank
chamber) is used as the control pressure chamber in many cases. In
such a case, if a control pressure (pressure in the control
pressure chamber) is increased, the angle of the swash plate is
reduced and the discharge capacity is reduced, and if the control
pressure is reduced, the angle of the swash plate is increased and
the discharge capacity is increased (patent document 1, for
example).
[0004] In the control valve disclosed in the patent document 1,
however, in a ball valve as the high pressure valve portion, a
discharge pressure is applied in a direction closing a valve body.
Therefore, when control is performed to reduce the angle of the
swash plate to reduce the discharge capacity, there is concern that
the high pressure valve portion is closed unintentionally by the
discharge pressure, the control pressure is reduced, the angle of
the swash plate is increased and the discharge capacity is
increased.
[0005] In addition to the high pressure valve portion having the
ball valve, there is also a conventional high pressure valve
portion in which a valve body of the low pressure valve portion is
integrally formed on a spool valve as the high pressure valve
portion. In such a case, there is a problem that since a pressure
leaks from a clearance generated between a sleeve and a spool in
the high pressure valve portion, the actuation of the air
conditioning system delays when the cooling operation is
started.
[0006] Therefore, it is an object of the present invention to
obtain a control valve for a variable displacement compressor
capable of preventing a high pressure valve portion from being
unintentionally closed by increase of a discharge pressure, capable
of preventing an angle of a swash plate from increasing, and
capable of enhancing the actuating performance. Patent document 1:
International Publication WO2004/065789
DISCLOSURE OF INVENTION
[0007] According to the present invention, a control valve for a
variable displacement compressor comprises a high pressure valve
portion provided in an introducing-side communication passage which
brings a discharge flow path and a control pressure chamber of the
variable displacement compressor into communication with each
other, and a low pressure valve portion provided in a
discharging-side communication passage which brings an intake flow
path and the control pressure chamber into communication with each
other, in which degree of opening for communication of the high
pressure valve portion and the low pressure valve portion are
variably controlled, thereby varying a pressure in the control
pressure chamber to change an angle of a swash plate, wherein the
control valve further comprises a position control unit which
controls advancing/retracting positions of a high pressure-side
valve body of the high pressure valve portion and a low
pressure-side valve body of the low pressure valve portion, as a
position of the high pressure-side valve body positioned by the
position control unit is closer to one side, a degree of opening
for communication of the high pressure valve portion is more
widened, a pressure on the side of a discharge flow path acting on
the high pressure-side valve body is weakened, as a position of the
low pressure-side valve body positioned by the position control
unit is closer to the other side, a degree of opening for
communication of the low pressure valve portion is more widened,
and when the high pressure-side valve body and the low
pressure-side valve body are integrally positioned on the one side
by the position control unit and the low pressure-side valve body
is positioned on the other side by the position control unit, the
high pressure-side valve body and the low pressure-side valve body
are separated from each other.
[0008] According to the present invention, when the high
pressure-side valve body and the low pressure-side valve body are
positioned on the one side by the position control unit, the low
pressure valve portion is fully closed.
[0009] According to the present invention, there is provided an
urging unit which urges, of the high pressure-side valve body and
the low pressure-side valve body, only the low pressure-side valve
body toward the other side.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic diagram of apparatus configurations of
a variable displacement compressor and a control valve according to
an embodiment of the present invention.
[0011] FIG. 2 is a vertical sectional view of the control valve for
the variable displacement compressor according to the embodiment of
the present invention, and shows that a high pressure valve portion
is closed and a low pressure valve portion is opened.
[0012] FIG. 3 is an enlarged view of a portion A in FIG. 2.
[0013] FIG. 4 is an enlarged view of a portion B in FIG. 2.
[0014] FIG. 5 is a vertical sectional view of the control valve for
the variable displacement compressor according to the embodiment of
the present invention, and shows that the high pressure valve
portion is opened and the low pressure valve portion is closed.
[0015] FIG. 6 is a graph showing a correlation between a position
of a movable portion of the control valve for the variable
displacement compressor and opening areas of the high pressure
valve portion and the low pressure valve portion according to the
embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0016] An embodiment of the present invention will be explained
below in detail with reference to the accompanying drawings. FIG. 1
is a schematic diagram of apparatus configurations of a variable
displacement compressor and a control valve according to the
embodiment, FIG. 2 is a vertical sectional view of the control
valve, and shows that a high pressure valve portion is closed and a
low pressure valve portion is opened, FIG. 3 is an enlarged view of
a portion A in FIG. 2, FIG. 4 is an enlarged view of a portion B in
FIG. 2, FIG. 5 is a vertical sectional view of the control valve,
and shows that the high pressure valve portion is opened and the
low pressure valve portion is closed, and FIG. 6 is a graph showing
a correlation between a position of a movable portion of the
control valve and opening areas of the high pressure valve portion
and the low pressure valve portion.
[0017] As shown in FIG. 1, a control valve 1 according to the
present embodiment controls a control pressure Pc which changes an
inclination angle of a swash plate 2a to change a discharge
capacity of a variable displacement compressor 2, and the control
valve 1 controls a pressure (control pressure) Pc in a case chamber
3 as a control pressure chamber for example. In this case, the
lower the pressure Pc in the case chamber 3 is, the greater a
pressure difference applied to a piston in the variable
displacement compressor 2 becomes and the discharge capacity is
increased. On the contrary, the higher the pressure in the case
chamber 3 is, the lower the discharge capacity becomes.
[0018] The control pressure Pc is produced as an intermediate
pressure between a pressure of refrigerant (discharge pressure) Pd
in a discharge flow path 4 (e.g., discharge port) and a pressure of
refrigerant (intake pressure) Ps in an intake flow path 5 (e.g.,
intake port). For this purpose, the control valve 1 includes a high
pressure valve portion 7 and a low pressure valve portion 9. The
high pressure valve portion 7 is provided in an introducing-side
communication passage 6 which brings the discharge flow path 4 and
the case chamber 3 into communication with each other. The high
pressure valve portion 7 variably controls a degree of opening for
communication of the introducing-side communication passage 6. The
low pressure valve portion 9 is provided in a discharging-side
communication passage 8 which brings the intake flow path 5 and the
case chamber 3 into communication with each other. The low pressure
valve portion 9 variably controls a degree of opening for
communication of the discharging-side communication passage 8. By
adjusting these degrees of opening for communication, the control
pressure Pc is produced. In the case of such a configuration, as
the degree of opening for communication of the high pressure valve
portion 7 is larger, the control pressure Pc becomes closer to the
discharge pressure Pd and becomes higher, and as the degree of
opening for communication of the low pressure valve portion 9 is
larger, the control pressure Pc becomes closer to the intake
pressure Ps and becomes lower. By controlling the degree of opening
for communication of the high pressure valve portion 7 and the
degree of opening for communication of the low pressure valve
portion 9, it is possible to produce the control pressure Pc while
suppressing the refrigerant from flowing out from the discharge
flow path 4 toward the intake flow path 5 and while reducing the
energy loss.
[0019] In the present embodiment, the flow path (including the
introducing-side communication passage 6 and the discharging-side
communication passage 8) of refrigerant used for producing the
control pressure Pc is also used as a refrigerant circulating path
in the case chamber 3, and the flow path is used for lubricating
and cooling a sliding portion. For this reason, an opening 6a of
the introducing-side communication passage 6 facing the case
chamber 3 and an opening 8a of the discharging-side communication
passage 8 facing the case chamber 3 are appropriately separated
from each other, and a refrigerant path extending from the high
pressure valve portion 7 to the low pressure valve portion 9 is
long for some distance. Therefore, a pressure Pa in the high
pressure valve portion 7 on the side of the case chamber 3 is
slightly higher than a pressure Pc2 in the low pressure valve
portion 9 on the side of the case chamber 3.
[0020] As shown in FIG. 2, the control valve 1 includes a solenoid
10 in which a solenoid as a position control unit is incorporated,
and a valve portion 11 in which the high pressure valve portion 7
and the low pressure valve portion 9 are incorporated.
[0021] In the valve portion 11, a valve body (high pressure-side
valve body 7a) of the high pressure valve portion 7 and a valve
body (low pressure-side valve body 9a) of the low pressure valve
portion 9 are positioned and abutted against each other in tandem
in an advancing/retracting direction of a movable portion 10a of
the solenoid, and the valve bodies are pushed against the movable
portion 10a by coil springs 14 and 16 as an urging unit. By making
the advancing/retracting position of the movable portion 10a
variable, positions of the high pressure-side valve body 7a and the
low pressure-side valve body 9a are made variable, and the degree
of opening for communication of the high pressure valve portion 7
and the low pressure valve portion 9 can be controlled. In the
present embodiment, the low pressure-side valve body 9a is
positioned on the side closer to the movable portion 10a, and the
high pressure-side valve body 7a is positioned on the side further
from the movable portion 10a. In the following description, the
direction of the arrow X in FIGS. 2 to 5 is called a leading end
side, and the opposite direction is called a base end side for
convenience sake. The movable portion 10a, the low pressure-side
valve body 9a and the high pressure-side valve body 7a advance and
retract along the X direction. The X direction extends along axial
directions of a sleeve 12, a spool 13 and the movable portion 10a
of the solenoid.
[0022] The valve portion 11 includes a substantially cylindrical
sleeve 12 formed with a through hole 12a in its longitudinal
direction. The through hole 12a has a circular cross section. The
spool 13 is inserted into the through hole 12a with an appropriate
clearance, and the spool 13 can advance and retract in the through
hole 12a along its longitudinal direction.
[0023] The high pressure valve portion 7 is formed on the leading
end side of the valve portion 11. A concrete configuration of the
high pressure valve portion 7 will be explained with reference to
FIGS. 2 and 3.
[0024] A bottomed cylindrical recess 12b is formed on the leading
end side of the through hole 12a of the sleeve 12. The recess 12b
has a diameter greater than that of the through hole 12a. A side of
an opening 12e of the recess 12b is closed with a lid 12d.
[0025] An umbrella-like poppet 13a is formed on a leading end of
the spool 13. The poppet 13a projects slightly radially outward of
the through hole 12a. The poppet 13a is accommodated in the recess
12b. In a state shown in FIGS. 2 and 3, a bottom surface 13b of the
poppet 13a and a bottom surface 12c of the recess 12b are abutted
against each other. In the present embodiment, the poppet 13a
corresponds to the high pressure-side valve body 7a of the high
pressure valve portion 7, and the bottom surface 12c of the recess
12b corresponds to its sealing surface (sitting surface).
[0026] The coil spring 14 as an urging unit is interposed between
the lid 12d and the poppet 13a. The poppet 13a is urged toward the
base end side in the X direction, in the closing direction of the
high pressure-side valve body 7a by the coil spring 14.
[0027] A lateral hole port 12f intersecting with the through hole
12a is formed in the sleeve 12 at a location separating away from
the opening 12e on the leading end side of the through hole 12a
toward the base end side in the X direction by a predetermined
distance. A diameter-reduced portion 13c which is narrowed is
formed in the spool 13 from the bottom surface 13b of the poppet
13a to a location opposed to the lateral hole port 12f. The
diameter-reduced portion 13c has a substantially constant circular
cross section.
[0028] A side of the introducing-side communication passage 6 on
the side of the case chamber 3 which is not shown in FIGS. 2 or 3
is in communication with the recess 12b through a through hole 12g
formed in the lid 12d, and a side of the introducing-side
communication passage 6 on the side of the discharge flow path 4 is
in communication with the lateral hole port 12f. A pressure in the
recess 12b, i.e., a back pressure of the poppet 13a becomes a
control pressure (Pa), and a pressure in a gap 12h corresponding to
the lateral hole port 12f and the diameter-reduced portion 13c of
the spool 13 becomes the discharge pressure Pd.
[0029] The discharge pressure Pd is applied to an end surface of
the diameter-reduced portion 13c of the spool 13 on the side of the
leading end in the X direction toward the leading end side of the X
direction, and the discharge pressure Pd is applied to an end
surface of the diameter-reduced portion 13c of the spool 13 on the
side of the base end in the X direction toward the leading end side
in the X direction. Therefore, the discharge pressure Pd applied to
the spool 13 is weakened (offset) in the axial direction of the
spool 13.
[0030] In the configuration described above, if the spool 13 moves
toward the leading end side in the X direction and the poppet 13a
as the high pressure-side valve body 7a is separated away from the
bottom surface 12c as the sitting surface, the high pressure valve
portion 7 is opened and the introducing-side communication passage
6 is brought into communication. The degree of opening for
communication of the high pressure valve portion 7 becomes larger
in accordance with a distance of the poppet 13a separated away from
the bottom surface 12c. A state where the spool 13 is located at
the nearest position of the base end side in the X direction and
the poppet 13a sits on the bottom surface 12c corresponds to a
state where the high pressure valve portion 7 closes. In this
state, the introducing-side communication passage 6 is shut.
According to this configuration, the poppet 13a is pushed against
the bottom surface 12c such that the poppet 13a conforms to the
bottom surface 12c, thereby enhancing the sealing performance of
the high pressure valve portion 7. The position of the poppet 13a
in the X direction, i.e., the degree of opening for communication
of the high pressure valve portion 7 is controlled by a solenoid as
a later-described position control unit.
[0031] The low pressure valve portion 9 is formed on the valve
portion 11 on the side of the base end. A concrete configuration of
the low pressure valve portion 9 will be explained with reference
to FIGS. 2, 4, and 5.
[0032] Another lateral hole port 12i intersecting with the through
hole 12a is formed in the sleeve 12 at a location separating away
from the lateral hole port 12f by a predetermined distance toward
the base end side in the X direction. A diameter-reduced portion
13d which is narrowed from a location opposed to the lateral hole
port 12i to an end on the base end side is formed on the spool 13.
The diameter-reduced portion 13d has a substantially constant
circular cross section.
[0033] A clearance between the through hole 12a and a section of
the spool 13 (general portion 13e) existing between the lateral
hole port 12f and the lateral hole port 12i is narrowed so that
leakage of refrigerant between the lateral hole ports 12f and 12i
is reduced.
[0034] A bottomed cylindrical recess 12j is formed in the sleeve 12
on the base end side from the through hole 12a. The recess 12j has
a diameter greater than that of the through hole 12a. A leading end
of a sidewall 12k of the recess 12j is press-fitted into a recess
groove 10b formed in the leading end of the solenoid 10. With this
configuration, the valve portion 11 and the solenoid 10 are coupled
to each other.
[0035] A poppet 15 as the low pressure-side valve body 9a is
positioned in the recess 12j. A substantially cylindrical recess
15a is formed in the poppet 15. The diameter-reduced portion 13d of
the spool 13 is loosely inserted into the recess 15a.
[0036] An annular projection 15b is provided on the poppet 15 on
the leading end side in the X direction. As shown in FIG. 5, in a
state where the poppet 15 is located at the furthest position of
the leading end side in the X direction, the projection 15b is
inserted into the through hole 12a from its opening 12m on the base
end side of the through hole 12a, and a top surface 15c around the
projection 15b and a bottom surface 12n of the recess 12j abut
against each other. As described above, in the present embodiment,
the poppet 15 corresponds to the low pressure-side valve body 9a of
the low pressure valve portion 9, and the bottom surface 12n of the
recess 12j corresponds to its sealing surface (sitting
surface).
[0037] A coil spring 16 as an urging unit is interposed between the
bottom surface 12n and the poppet 15. The poppet 15 is urged toward
the base end side in the X direction, in the opening direction of
the low pressure-side valve body 9a by the coil spring 16.
[0038] A side of the discharging-side communication passage 8 (not
shown in FIGS. 2, 4, and 5) closer to the case chamber 3 is in
communication with the lateral hole port 12i, and a side of the
discharging-side communication passage 8 closer to the intake flow
path 5 is in communication with the recess 12j through a through
hole 12o formed in the sidewall 12k. With this configuration, a
pressure in the recess 12j, i.e., a back pressure of the poppet 15
is the intake pressure Ps, and a pressure in the lateral hole port
12i is the control pressure (Pc2).
[0039] That is, in the present embodiment, if the spool 13 moves
toward the base end side in the X direction and the poppet 15 as
the low pressure-side valve body 9a separates from the bottom
surface 12n as the sitting surface, the low pressure valve portion
9 opens and the discharging-side communication passage 8 is brought
into communication. The degree of opening for communication of the
low pressure valve portion 9 becomes larger in accordance with a
distance of the poppet 15 separated away from the bottom surface
12n. A state where the spool 13 is located at the furthest position
of the leading end side in the X direction and the poppet 15 sits
on the bottom surface 12n corresponds to a state where the low
pressure valve portion 9 is closed. In this state, the
discharging-side communication passage 8 is blocked.
[0040] According to this configuration, the poppet 15 is pushed
against the bottom surface 12n such that the poppet 15 conforms to
the bottom surface 12n, thereby enhancing the sealing performance
of the low pressure valve portion 9. The position of the poppet 15
in the X direction, i.e., the degree of opening for communication
of the low pressure valve portion 9 is controlled by a solenoid as
a later-described position control unit.
[0041] The movable portion 10a of the solenoid 10 is positioned on
the base end side of the poppet 15 as the low pressure-side valve
body 9a.
[0042] In the present embodiment, the movable portion 10a has such
a shape that a first member 10c located on the leading end side in
the X direction and a second member 10d located on the base end
side are arranged in the X direction and are integrally coupled to
each other. A recess 10e is formed in the first member 10c. A
leading end side of the recess 10e is widened in a conical shape
and a base end of the recess 10e is of a cylindrical shape. The
poppet 15 is loosely inserted into the recess 10e. At that time, a
bottom surface 15d of the poppet 15 abuts against a bottom surface
10f of the recess 10e, and the poppet 15 is pushed against the
first member 10c by the coil spring 16. An axial deviation between
the poppet 15 and the movable portion 10a can be absorbed by a
clearance between an inner wall of the recess 10e and an outer wall
of the poppet 15.
[0043] A flange 10g is formed on a leading end of the first member
10c. The flange 10g is latched together with an opening edge of a
recess 10i formed in leading end side of the casing 10h of the
solenoid 10, thereby limiting the movement of the movable portion
10a toward the base end side.
[0044] A coil spring 17 as an urging unit is interposed between a
back surface 10j of the flange 10g and a step 10k formed on a
sidewall of the recess 10i. The movable portion 10a is urged toward
the leading end side in the X direction by the coil spring 17.
[0045] The recess 10i is isolated by an annular plate-like
diaphragm 18. A peripheral edge of the diaphragm 18 is attached to
the casing 10h in a sealed manner, and a central portion of the
diaphragm 18 is nipped between the first member 10c and the second
member 10d in a sealed manner.
[0046] The recess 10i is in communication with the recess 12j
through a passage 10m which penetrates front and back surfaces of
the flange 10g. Therefore, a pressure in the recess 10i, i.e., a
pressure acting on a surface (front surface) of the diaphragm 18 on
the side of the leading end is the intake pressure Ps. A pressure
acting on a surface (back surface) of the diaphragm 18 on the side
of the base end is the atmospheric pressure. Therefore, if the
intake pressure Ps exceeds a predetermined value, the movable
portion 10a is moved toward the base end side by a pressure
difference acting on the diaphragm 18.
[0047] A shaft 19 is coupled to the movable portion 10a. The shaft
19 is urged toward the leading end side by a coil spring 20 as an
urging unit positioned on the base end side.
[0048] In the above configuration, if a coil 21 is energized, a
suction force acting toward the base end side is applied to the
movable portion 10a (second member 10d). By adjusting the suction
force by controlling current flowing to the coil 21, positions, in
the X direction, of the movable portion 10a, the poppet 15 as the
low pressure-side valve body 9a which abuts against the movable
portion 10a, and the poppet 13a as the high pressure-side valve
body 7a provided on the spool 13 which abuts against the poppet 15
are determined by balance between the suction force and the urging
forces of the coil springs 14, 16, 17, and 20 as the urging
unit.
[0049] If the movable portion 10a is moved toward the base end side
by controlling the current supplied to the coil 21 or by increasing
the intake pressure Ps acting on the diaphragm 18, the poppet 15 as
the low pressure-side valve body 9a is also moved toward the base
end side in association with the movable portion 10a by the spring
force of the coil spring 16 as the urging unit, and the poppet 13a
as the high pressure-side valve body 7a provided on the spool 13 is
also moved toward the base end side in association with the movable
portion 10a by the spring force of the coil spring 14 as the urging
unit.
[0050] According to the present embodiment, however, since poppet
15 and the spool 13 provided with the poppet 13a are not coupled to
each other and they can separate from each other, after the poppet
13a as the high pressure-side valve body 7a sits on the bottom
surface 12c as the sitting surface, the poppet 15 separates from
the spool 13 as shown in FIG. 2, and the degree of opening for
communication of only the low pressure valve portion 9 becomes
larger.
[0051] FIG. 6 shows the degree of opening for communications of the
high pressure valve portion 7 and the low pressure valve portion 9
with respect to the position, in the X direction, of the movable
portion 10a in the control valve 1 having the configuration
described above. In FIG. 6, the lateral axis shows a position of
the movable portion 10a in the X direction, the right side is the
base end side, and the left side is the leading side. The vertical
axis shows the degree of opening for communication (an area of
opening).
[0052] The degree of opening for communication of the high pressure
valve portion 7 is linearly varied depending upon the position of
the movable portion 10a, i.e., the position of the poppet 13a. That
is, in a state where the movable portion 10a is located at the
furthest position of the leading end side (FIG. 5), the degree of
opening for communication of the high pressure valve portion 7
becomes the maximum, the degree of opening for communication of the
high pressure valve portion 7 is linearly reduced as the position
of the movable portion 10a is varied toward the base end side. When
the poppet 13a as the high pressure-side valve body 7a abuts
against the bottom surface 12c as the sitting surface, the high
pressure valve portion 7 closes and its degree of opening for
communication becomes 0. If the high pressure valve portion 7
closes, the supply of refrigerant into the case chamber 3 through
the introducing-side communication passage 6 is stopped, but
refrigerant can be supplied into the case chamber 3 due to leakage
from the clearance between the piston and the cylinder.
[0053] The degree of opening for communication of the low pressure
valve portion 9 is also varied in accordance with the position of
the movable portion 10a, but the manner of variation of the degree
of opening for communication differs depending upon the position of
the movable portion 10a. That is, when the movable portion 10a is
located at the furthest position of the leading end side direction,
the poppet 15 as the low pressure-side valve body 9a abuts against
the bottom surface 12n as the sitting surface and the low pressure
valve portion 9 is closed.
[0054] If the position of the movable portion 10a is varied to the
base end side, the poppet 15 separates from the bottom surface 12n.
While the poppet 15 is not separated from the bottom surface 12n so
much, the degree of opening for communication is varied linearly
(region 1). Thereafter, even if the distance between the poppet 15
and the bottom surface 12n is increased, if the projection 15b is
still inserted into the through hole 12a, the clearance between the
projection 15b and the through hole 12a occupies the most of the
degree of opening for communication of the low pressure valve
portion 9, and this degree of opening for communication is
equivalent to a fixed orifice. Therefore, in this section, the
degree of opening for communication is varied substantially
constantly (region 2). Thereafter, if the projection 15b is pulled
out from the through hole 12a, the degree of opening for
communication of the low pressure valve portion 9 is linearly
increased in accordance with the distance between the poppet 15 and
the bottom surface 12n (region 3). In this region 3, the poppet 15,
i.e., the low pressure-side valve body 9a separates from the poppet
13a, i.e., the spool 13 having the high pressure-side valve body 7a
(gap G). Therefore, the high pressure valve portion 7 is closed and
the movement of the high pressure-side valve body 7a toward the
base end side is limited, but irrespective of this, the degree of
opening for communication of the low pressure valve portion 9 can
swiftly be larger.
[0055] According to the present embodiment, as described above, the
discharge pressure Pd acting to the poppet 13a as the high
pressure-side valve body 7a acts on both the base end side and the
leading end side of the spool 13 in the X direction and the
discharge pressure Pd is weakened. Therefore, unlike the
conventional technique, it is possible to avoid a case where when
the high pressure valve portion is opened, the high pressure valve
portion is closed by the discharge flow path side pressure Pd
acting on the high pressure-side valve body and a pressure in the
case chamber is reduced. Thus, it is possible to avoid a case where
in a state in which the angle of the swash plate 2a of the variable
displacement compressor 2 is small, the degree of opening for
communication of the high pressure valve portion 7 is reduced or
closed, a pressure in the case chamber 3 is reduced and the angle
of the swash plate 2a is increased.
[0056] That is, according to the present embodiment, it is possible
to keep the angle of the swash plate 2a small and to reliably
obtain a state where there is almost no discharge capacity.
Therefore, this is suitably applied to a variable displacement
compressor for a so-called clutch-less system. In this case, as
compared with a system which stops rotation of a compressor using a
clutch, there is a merit that the number of parts is reduced, the
apparatus configuration can be simplified and its weight can be
reduced.
[0057] According to the present embodiment, when the poppet 15 as
the low pressure-side valve body 9a is positioned on the side of
the base end by the solenoid 10 as the position control unit, the
poppet 13a as the high pressure-side valve body 7a and the poppet
15 as the low pressure-side valve body 9a are separated from each
other. Therefore, the degree of opening for communication of the
low pressure valve portion 9 can be widened and the poppet 15 is
not subjected to any constraints by the poppet 13a. Therefore, when
the variable displacement compressor 2 is started, the degree of
opening for communication of the low pressure valve portion 9 can
be larger more swiftly, the control pressure Pc in the case chamber
3 can be reduced, the angle of the swash plate 2a can be increased,
and a necessary discharge capacity can be secured more swiftly.
[0058] Further, since the high pressure-side valve body 7a and the
low pressure-side valve body 9a can be separated from each other,
even if a discharge pressure Pd acts on the high pressure-side
valve body 7a toward the leading end side in the X direction, the
movement of the low pressure-side valve body 9a toward the base end
side in the X direction is not hindered.
[0059] According to the present embodiment, the low pressure valve
portion 9 is fully closed when the poppet 13a as the high
pressure-side valve body 7a and the poppet 15 as the low
pressure-side valve body 9a are positioned on the side of the
leading end by the solenoid 10 as the position control unit.
Therefore, it becomes easy to keep the control pressure Pc in the
case chamber 3 high, the leaking flow in the low pressure valve
portion 9 can be reduced and the energy loss can be reduced
correspondingly.
[0060] Since the low pressure valve portion 9 is configured such
that it closes, the degree of opening for communication when the
low pressure valve portion 9 is closed is naturally small as
compared with a case where the low pressure valve portion 9 is
configured such that it does not close. However, according to the
present embodiment, since the high pressure-side valve body 7a and
the low pressure-side valve body 9a can be separated from each
other, the degree of opening for communication of the low pressure
valve portion 9 can be larger more swiftly as compared with a case
where the high pressure-side valve body 7a and the low
pressure-side valve body 9a are integrally formed as one piece, and
a state where the low pressure valve portion 9 is closed, i.e., a
state where the control pressure Pc in the case chamber 3 is high
can be switched, more swiftly, to a state where the low pressure
valve portion 9 is opened, i.e., a state where the control pressure
Pc in the case chamber 3 is low, and the control response can be
enhanced.
[0061] Furthermore, according to the present embodiment, the poppet
13a and the poppet 15 can be separated more swiftly by the coil
spring 17 which does not urge the poppet 13a and which urges only
the poppet 15 toward the base end side. Therefore, the degree of
opening for communication of the low pressure valve portion 9 can
be larger more swiftly, and the control response can be
enhanced.
[0062] While a preferred embodiment of the present invention has
been described above, the invention is not limited to the
embodiment and can be variously modified. For example, the poppet
valve can be changed to a ball valve or a needle valve. The
direction of the suction force cause by the solenoid, the
configuration to generate the suction force, the configuration of
the valve portion, the configuration of the urging unit and the
like are not limited to those of the embodiment.
INDUSTRIAL APPLICABILITY
[0063] The present invention can be utilized as a control valve for
a variable displacement compressor.
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