FIELD OF THE INVENTION
The present invention relates to an expansion valve for
controlling the flow of refrigerant supplied to an evaporator according to the temperature
of the refrigerant that is equipped to an air conditioning device for automobiles
and the like.
DESCRIPTION OF THE RELATED ART
EP-A-0 691 517
discloses a unit type expansion valve according to the preamble of claim
1. Similar constructions are shown in
EP-A-0 959 310
EP-A-0 781 970 A1
A further example of a conventional expansion valve is
Japanese Patent Laid-Open Publication No. 2000-304381
The conventional expansion valve requires a large number
of components such as a valve receiving member, spring, adjusting screw and the
like, thereby making it difficult to reduce the size and the weight of the expansion
Also, there was a possibility that disadvantage such as
leaking of refrigerant from a valve chamber through the control screw area may arise.
SUMMARY OF THE INVENTION
In response to the request for reducing size and weight
of the air conditioners in automobiles, the present invention aims to provide an
expansion valve with simplified structure and reduced assembly process.
In order to overcome the problems mentioned above, the
invention provides an expansion valve according to claim 1.
The expansion valve of the present invention is basically
equipped with a valve body; a first path formed inside the valve body through which
high-pressure refrigerant flows; a valve chamber with a bottom formed inside the
first path; a second path formed inside the valve body parallel to the first path,
through which refrigerant flowing toward an evaporator flows; an orifice member
including a throttle passage that communicates the valve chamber with the second
path, the orifice member being press-fitted into the valve body; a valve member
disposed facing the orifice member; a third path through which refrigerant exiting
the evaporator flows; an actuating rod for operating the valve member; an actuating
device for driving the actuating rod; an opening formed to the valve body that communicates
the third path with the actuating device; and a guide member for slidably guiding
the actuating rod, the guide member being press-fitted into an opening communicating
the second path with the third path of the valve body; a vibration insulating member.
Also, the inner diameter size of the opening formed to
the valve body and communicating the third path with the actuating device is larger
than the inner diameter size of the opening into which the guide member is press-fitted,
and the inner diameter size of the opening into which the guide member is press-fitted
is larger than the inner diameter size of the opening into which the orifice member
Moreover, the valve member is fixed to a valve supporting
member, and is further equipped with a spring provided between the valve supporting
member and the bottom of the valve chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
- FIG. 1 is a cross-sectional view of the expansion valve of the present invention;
- FIG. 2 is a right side view of FIG. 1; and
- FIG. 3 is a perspective view of the vibration insulating member.
FIG. 1 is a cross-sectional view of the expansion valve
of the present invention, and FIG. 2 is a right side view of the same.
The expansion valve denoted as a whole by reference 1 includes
a square rod-shaped valve body 10 made of aluminum alloy and the like, and a first
path 20 for guiding the high-pressure refrigerant provided to the valve body 10.
The first path 20 is connected to a valve chamber 22 having a bottom wall, and an
orifice member 40 is press-fitted and fixed to the opening of the valve chamber
A spherical valve member 30 is fixed to the supporting
member 32 by welding, and is disposed inside the valve chamber 22. The supportingmember
32 forces the valve member 30 toward the orifice member 40 at all times with a spring
The orifice member 40 includes an opening 42 at the central
portion thereof, and forms a flow path of the refrigerant between the valve member
30. A vibration insulating member 50 is fitted to the inner diameter portion of
the orifice member 40 so as to prevent vibration of the valve member.
The refrigerant passing through the orifice member 40 is
sent toward the evaporator through a second path 24. The refrigerant returning from
the evaporator is sent towards the compressor side through a third path 26.
The end portion of the valve body 10 opposite to the valve
chamber 22 is equipped with a valve member driving device (hereinafter referred
to as power element) 70. Thepowerelement 70 includes a can member 72 formed by welding
an upper lid 72a and a lower lid 72b together. A diaphragm 80 is interposed between
the upper lid 72a and the lower lid 72b. The can body 72 is fixed to the valve body
10 via a screw portion 74, and is sealed by a sealingmember 76. A pressure chamber
82 is formed between the diaphragm 80 and the upper lid 72a. The pressure chamber
82 is filled with actuating fluid, and is sealed by a plug member 84.
A stopper member 90 is provided to the other side of the
diaphragm from the pressure chamber 82. The refrigerant in the third path is lead
to the rear surface of the stopper member via an opening 12. The stopper member
90 slides to follow the displacement of the diaphragm 80. The stopper member 90
grips an actuating rod 60. The other end of the actuating rod is in contact with
the valve member 30. The displacement of the diaphragm 80 drives the valve member
30 through the actuating rod 60, and controls the cross-sectional area of the flow
path between the valve member and the orifice member 40.
A guide member 100 press-fitted to the valve body 10 includes
a step portion 110, and is fixed to the valve body 10 with its position strictly
determined. A ring-shaped sealing member 120 is inserted to the inner diameter portion
of the guide member 100, and is fixed by a stopper 130 such as a push nut and the
like. The sealing member 120 blocks the flow of refrigerant between the second path
24 and the third path 26.
FIG. 3 is a perspective view indicating the structure of
the vibration insulating member 50.
The vibration insulating member 50 includes a ring portion
52 formed by bending a metal plate having high elasticity into a circular shape,
and a retaining portion 54 formed by providing a slit to the ring portion and bending
the metal to the inner direction of the ring portion.
Both end portions 52a and 52b of the ring portion 52 are
formed so as to overlap one another. The ring portion 52 is inserted to the inner
diameter portion of the orifice member 40 in the state in which the diameter of
the ring portion 52 is reduced. By utilizing the elastic force of the ring portion
restoring its original diameter, the vibration insulating member 50 is positioned
inside the orifice member 40.
The retaining portion 54 contacts the outer periphery of
the spherical valve member 30, and restrains the vibration of the valve member 30.
In the present embodiment, three retaining portions 54
are provided. However, it is also possible to provide four retaining portions 54.
Next, the assembly procedure of the present expansion valve
will be explained.
First, the supporting member 32 with the spring 34 and
the valve member 30 welded thereto is inserted inside the valve chamber 22 with
a bottom via the opening 12 on the side of the valve body 10 for fitting the power
Next, the assembled orifice member 40 fitted with the vibration
insulating member 50 is inserted via the opening 12, and is press-fitted into the
opening 16 of the valve chamber 22.
The orifice member 40 is press-fitted by using a proper
press-fitting tool, and is further fixed by caulking when necessary.
Then, the guide member 100 having the actuating rod 60
inserted thereto is inserted from the opening 12, and is press-fitted to the stepped
hole 14 of the valve body 10. The axial position of the guide member 100 is determined
by the stepped portion 110. The guide member is further fixed by caulking, if necessary.
Finally, the assembled power element 70 is screwed onto
the valve body 10 at the screw portion 74, thereby completing assembly of the expansion
The expansion valve of the present invention is formed
so as to have openings where the inner diameter of the opening is decreased sequentially
from the opening side to which the power element is attached, and to have the hole
with a bottom at the far end thereof. The present invention forms the valve chamber
by mounting the valve member and the assembled orifice member to this opening, and
press-fitting the assembled guide member that guides the actuating rod, so as to
form the paths for the high-pressure-side refrigerant and the low-pressure-side
With the structure mentioned above, the number of overall
components of the expansion valve can be reduced, and the required assembling time
can also be reduced.