Refrigeration – Refrigeration producer – Compressor-condenser-evaporator circuit
Reexamination Certificate
2001-11-09
2004-03-09
Jones, Melvin (Department: 3744)
Refrigeration
Refrigeration producer
Compressor-condenser-evaporator circuit
C062S528000
Reexamination Certificate
active
06701744
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an electrically operated needle valve used for controlling the amount of flow of a refrigerant in a refrigerating circuit and to a refrigerating system provided with such an electrically operated needle valve.
BACKGROUND ART
Referring to
FIG. 14
, there is shown a construction of an electrically operated expansion valve Z
0
which is used for controlling the amount of flow of a refrigerant in a refrigerating circuit. A concrete description of the construction of the prior art electrically operated expansion valve Z
0
will be made below for providing a description of the present invention which will be set forth later.
In
FIG. 14
, the electrically operated expansion valve Z
0
has a valve main body
1
, a needle
2
, and a casing
3
. The valve main body
1
is formed into a different diameter body including a flow path formation portion
1
a
of larger diameter which is positioned on the side of one axial end of the valve main body
1
, a screw thread formation portion
1
c
of smaller diameter which is positioned on the side of the other axial end of the valve main body
1
, and a shoulder portion
1
b
of medium diameter which is positioned between the flow path formation portion
1
a
and the screw thread formation portion
1
c
. The shoulder portion
1
b
and the screw thread formation portion
1
c
are inserted into an internal space
30
of the casing
3
through an opening
33
formed in one end face of the casing
3
. And, the valve main body
1
is made integral with the casing
3
with the shoulder portion
1
b
and the screw thread formation portion
1
c
inserted in the casing
3
.
The flow path formation portion
1
a
of the valve main body
1
is provided with a refrigerant flow path
9
. The refrigerant flow path
9
is composed of a refrigerant introduction portion
11
and a refrigerant withdrawal portion
12
, these portions
11
and
12
being approximately orthogonal to each other. Formed at an opening edge of the refrigerant introduction portion
11
is a valve seat portion
15
. A refrigerant introduction pipe
13
is connected to the refrigerant introduction portion
11
, whereas a refrigerant withdrawal pipe
14
is connected to the refrigerant withdrawal portion
12
.
A needle fit/insert aperture
16
having a given diameter is formed in the valve main body
1
. The needle fit/insert aperture
16
is so formed as to extend from the refrigerant flow path
9
of the flow path formation portion
1
a
to an end of the screw thread formation portion
1
c
. And, one end of the needle fit/insert aperture
16
opens to the refrigerant flow path
9
, whereas the other end of the needle fit/insert aperture
16
opens to an end face of the screw thread formation portion
1
c.
The needle
2
is slidably inserted into the needle fit/insert aperture
16
. Formed at one end of the needle
2
is a valve head portion
20
. The needle
2
travels back and forth along its axial direction, thereby increasing and decreasing the area of a passage between the valve head portion
20
and the valve seat portion
15
. Because of such increase and decrease in path area, the amount of flow of a refrigerant flowing from the refrigerant introduction pipe
13
to the refrigerant withdrawal pipe
14
is controlled. Further, when the valve head portion
20
seats against the valve seat portion
15
, the refrigerant flow path
9
is placed in the fully closed state. As a result, the circulation of the refrigerant is stopped.
The needle
2
is composed of a stepped shaft body including a sliding shaft portion
2
a
of larger diameter which is positioned on the side of the valve head portion
20
and a supporting shaft portion
2
b
of smaller diameter. And, the sliding shaft portion
2
a
is slidably supported by the valve main body
1
and the axial center position of the needle
2
is held. An extremely narrow needle fit/insertion clearance
17
is defined between the inner peripheral surface of the needle fit/insert aperture
16
and the sliding shaft portion
2
a
of the needle
2
. Further, defined between the inner peripheral surface of the needle fit/insert aperture
16
and the supporting shaft portion
2
b
is an inner peripheral clearance
22
which is of larger clearance size than that of the needle fit/insert clearance
17
.
On the other hand, a pressure equalization aperture
18
having a given diameter is formed in the shoulder portion
1
b
of the valve main body
1
so that the needle fit/insert aperture
16
passing through the axial center portion of the shoulder portion
1
b
and the lower end of the internal space
30
of the casing
3
communicate to each other. That is, by virtue of the formation of the pressure equalization aperture
18
of given diameter, the needle fit/insert clearance
17
and a first space portion
31
(which will be described later) communicate with each other.
Further, formed on the outer peripheral surface of the screw thread formation portion
1
c
of the valve main body
1
is an external thread. A rotor portion
10
constituting a part of an electrically operated means X is disposed on the diameterwise outside of the screw thread formation portion
1
c
. The electrically operated means X axially drives the needle
2
and is composed of a so-called stepping motor. The electrically operated means X has the rotor portion
10
and an electromagnet
5
disposed on the outer peripheral side of the casing
3
.
The rotor portion
10
has a screw thread formation member
7
and a spacer
6
. The screw thread formation member
7
is formed into a bottomed tubular-like shape. Formed on the inner peripheral surface of a peripheral wall portion
7
a
of the screw thread formation member
7
is an internal thread which meshes with the external thread of the screw thread formation portion
1
c
of the valve main body
1
. The spacer
6
is formed into a tubular-like shape having collars at both ends thereof. A permanent magnet
4
is positioned on the outer peripheral side of the spacer
6
. On the other hand, the peripheral wall portion
7
a
of the screw thread formation member
7
is force-fit in the inner peripheral side of the spacer
6
and fixed there rigidly.
The rotor portion
10
is inserted from above the screw thread formation portion
1
c
of the valve main body
1
with the screw thread formation member
7
engaging with the screw thread formation portion
1
c
so that the rotor portion
10
is attached to the valve main body
1
. Accordingly, the rotor portion
10
rotates in correspondence to the amount of energization (pulse value) of the electromagnetic
5
and makes a relative movement in the axial direction of the screw thread formation portion
1
c
with respect to the screw thread formation portion
1
c
of the valve main body
1
.
The needle
2
is connected to the rotor portion
10
so that the needle
2
is placed in the opened or closed state by the axial movement of the rotor
10
. That is, the upper end of the needle
2
passes through an end face portion
7
b
of the screw thread formation member
7
and projects therefrom upwardly. The projecting end of the needle
2
is provided with a retaining member
34
. The retaining member
34
prevents the needle
2
from slipping downwardly from the screw thread formation member
7
. Further, a compression spring
35
is positioned between a step portion between the sliding shaft portion
2
a
and supporting shaft portion
2
b
of the needle
2
and the lower surface of the end face portion
7
b
of the screw thread formation member
7
. The spring
35
constantly applies pressing force to the needle
2
and to the screw thread formation member
7
in the direction in which the retaining member
34
abuts against the end face portion
7
b
of the screw thread formation member
7
.
Accordingly, in the range up to the time that the valve head portion
20
seats against the valve seat portion
15
, the needle
2
travels with the axial movement of the rotor portion
10
for the increase or decrease in passage area. On the other h
Domyo Nobuo
Esumi Hajime
Taira Shigeharu
Yajima Ryuzaburo
Daikin Industries Ltd.
Jones Melvin
Nixon & Peabody LLP
Studebaker Donald R.
LandOfFree
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