JP3786518B2 - Expansion valve with solenoid valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an expansion valve with an electromagnetic valve for controlling the flow rate of refrigerant sent to an evaporator in a refrigeration cycle used for an air conditioner for automobiles and the like.
[0002]
[Prior art]
In general, the expansion valve controls the flow rate of the refrigerant fed into the evaporator by driving the valve with a power element that operates by sensing the temperature change of the low-pressure refrigerant delivered from the outlet of the evaporator.
[0003]
However, in a refrigeration cycle with a plurality of evaporators, it is a waste of energy if the refrigerant is allowed to flow to an evaporator that does not need to be used, so that each expansion valve can be forcibly closed by a solenoid. It has become.
[0004]
[Problems to be solved by the invention]
However, in order to forcibly close the valve body of the expansion valve, the valve body must be pushed against the opening force of the power element, so that the solenoid becomes large, with a large space and large power consumption. There were disadvantages.
[0005]
Accordingly, the present invention provides an expansion valve with a solenoid valve that can be switched between a flow control state corresponding to the temperature of the low-pressure refrigerant delivered from the evaporator and a fully closed state with a small solenoid that consumes less power. With the goal.
[0006]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the expansion valve with a solenoid valve of the present invention is disposed so as to face the valve seat formed in the middle of the high-pressure refrigerant flow path through which the high-pressure refrigerant toward the inlet of the evaporator passes from the upstream side. A valve body, a pressure regulating chamber formed to communicate with the high-pressure refrigerant flow path downstream from the valve seat via a leak path, and one end side passing through the valve seat so as to move together with the valve body A piston-like member that is connected to the valve body and is disposed facing the pressure regulating chamber so that the other end receives the pressure in the pressure regulating chamber, and has a channel cross-sectional area larger than the leak path. A pilot hole penetrating through the piston-like member and having one end opened on the back side of the valve body and the other end opened in the pressure regulating chamber, and the temperature of the low-pressure refrigerant sent out from the outlet of the evaporator Powered by a power element that operates by sensing pressure changes A first pilot hole opening / closing valve that opens and closes the pilot hole, and a second pilot hole opening / closing valve that is driven by a solenoid to open and close the opening of the pilot hole on the valve body rear side. .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an expansion valve used in, for example, a refrigeration cycle of an automotive air conditioner (car air conditioner). In the main body block 1 of the expansion valve, a high-pressure refrigerant flow path 2 through which a high-pressure refrigerant directed to the inlet of the evaporator (not shown) and a low-pressure refrigerant flow path 3 through which the low-pressure refrigerant sent from the evaporator pass are formed in parallel. Has been.
[0008]
The high-pressure refrigerant flow path 2 is formed to be bent in a crank shape on the way. A valve seat 4 having a narrow pipe diameter is formed in the inner peripheral portion of the high-pressure refrigerant flow path 2 at that portion, and a conical valve body 5 for controlling the flow rate of the high-pressure refrigerant is provided in the valve seat 4. Are arranged opposite to each other from the upstream side.
[0009]
Therefore, when the valve body 5 is in contact with the valve seat 4, the flow of the refrigerant to the evaporator is stopped, the flow rate of the refrigerant increases as the valve body 5 retreats from the valve seat 4, and the refrigerant is insulated. It is sent to the evaporator while expanding.
[0010]
On the extension of the central axis of the valve seat 4, a through hole 7 having a diameter larger than that of the valve seat 4 is formed perpendicular to the low pressure refrigerant flow path 3, and the power element 10 is formed at the outer end of the through hole 7. Is attached.
[0011]
The power element 10 is formed with a temperature-sensitive greenhouse 12 that is partitioned by a diaphragm 11 from the refrigerant in the low-pressure refrigerant flow path 3. A gas having the same or similar characteristics as the refrigerant is sealed in the temperature-sensitive greenhouse 12, and the temperature of the refrigerant in the low-pressure refrigerant flow path 3 is sensed through the diaphragm 11, thereby the pressure in the temperature-sensitive greenhouse 12. Changes.
[0012]
A diaphragm receiving plate 13 urged by a compression coil spring 16 supported by a support cylinder 15 is in contact with the back surface of the diaphragm 11 (the surface outside the temperature-sensitive greenhouse 12). The diaphragm receiving plate 13 is stopped at a position where the pressure difference between the pressure and the biasing force of the compression coil spring 16 is balanced.
[0013]
The support cylinder 15 is fixed to the main body block 1 so as to cross the low-pressure refrigerant flow path 3 with the through hole 7 and the axis aligned, and the fixed end side of the compression coil spring 16 is supported by the support cylinder 15. Reference numeral 17 denotes a spring receiving nut that is screwed onto the support tube 15 so that the urging force of the compression coil spring 16 can be adjusted during assembly.
[0014]
A piston-like member 20 is loosely fitted in the through-hole 7 so as to be slidable in the axial direction, and the inside of the through-hole 7 serves as a pressure regulating chamber 21 for pilot-operating the valve body 5. The shaped member 20 receives the pressure in the pressure regulating chamber 21 at one end side.
[0015]
Although the space between the pressure regulating chamber 21 and the low pressure refrigerant flow path 3 is completely closed, the inside of the high pressure refrigerant flow path 2 and the pressure regulating chamber 21 located downstream of the valve seat 4 is a piston-like member. 20 and a through-hole 7 are connected with a narrow cross-sectional area through a fitting portion (leak path) 22.
[0016]
The piston-like member 20 is integrally connected to the valve body 5 via a connecting cylinder 24 arranged so as to pass through the valve seat 4, and a pilot hole 25 penetrating them in the axial direction is formed. Yes.
[0017]
The pilot hole 25 has a flow path cross-sectional area larger than that of the leak path 22, and one end of the pilot hole 25 is a high pressure upstream of the valve seat 4 in the back surface portion (the back side portion when viewed from the valve seat 4 side). The refrigerant channel 2 opens and the other end opens in the pressure regulating chamber 21.
[0018]
A first pilot valve body 27 formed in a spherical shape is arranged facing a valve seat 26 formed in the vicinity of the pressure regulation chamber side opening of the pilot hole 25 from the inside of the pilot hole 25, and is a piston-like member. It is urged in the closing direction by a weak compression coil spring 28 arranged in 20.
[0019]
Between the first pilot valve body 27 and the diaphragm receiving plate 13 of the power element 10, both ends of a rod 29 that is inserted in the support cylinder 15 so as to be capable of moving back and forth in the axial direction are in contact. Accordingly, the first pilot valve body 27 moves through the rod 29 according to the displacement of the diaphragm 11, and the space between the pilot hole 25 and the pressure regulating chamber 21 is opened and closed.
[0020]
A second pilot valve body 30 is disposed so as to face the opening on the back side of the valve body of the pilot hole 25. The second pilot valve body 30 is attached to the distal end portion of the movable iron core 41 of the solenoid 40 that is integrally attached to the main body block 1 by screwing.
[0021]
When the electromagnetic coil 42 is not energized, as shown in FIG. 1, the second pilot valve element 30 is a compression coil that is disposed between the movable iron core 41 and the fixed iron core 43. The pilot hole 25 is blocked by being pressed against the back surface of the valve body 5 by the urging force of the spring 44.
[0022]
Therefore, since the pilot hole 25 is always closed regardless of the state of the first pilot valve body 27, the inside of the pressure regulating chamber 21 is connected to the high-pressure refrigerant flow path 2 downstream from the valve seat 4 communicating via the leak path 22. The pressure is the same. As a result, the valve body 5 is pressed against the valve seat 4 by the urging force of the compression coil spring 31, and the high-pressure refrigerant flow path 2 is maintained in a completely closed state.
[0023]
When the electromagnetic coil 42 is energized, as shown in FIG. 2, the movable iron core 41 is attracted to the fixed iron core 43, and the second pilot valve body 30 is retracted from the back surface of the valve body 5, and the pilot hole 25 valve body back side opening will be in the open state.
[0024]
Since the force required at this time is only to compress the compression coil spring 44 interposed between the movable iron core 41 and the fixed iron core 43, the current value required for the electromagnetic coil 42 can be very small.
[0025]
When the second pilot valve body 30 is retracted from the back surface of the valve body 5, the pilot hole 25 is opened and closed by the first pilot valve body 27 driven by the power element 10.
[0026]
FIG. 3 shows that the power element 10 is operated by changes in the temperature and pressure of the low-pressure refrigerant flowing through the low-pressure refrigerant flow path 3, thereby pushing the first pilot valve body 27 away from the valve seat 26 via the rod 29. It shows the state that was done.
[0027]
In this state, the pilot hole 25 is opened and the inside of the pressure regulating chamber 21 communicates with the inside of the high-pressure refrigerant flow path 2 on the upstream side of the valve seat 4 so that the pressure becomes high. , The gap between the valve body 5 and the valve seat 4 is widened, and the flow rate of the refrigerant fed into the evaporator is increased.
[0028]
If there is a temperature drop (pressure rise) of the low-pressure refrigerant flowing through the low-pressure refrigerant flow path 3, the rod 29 is retracted from the first pilot valve body 27 and moved by the operation of the power element 10 as shown in FIG. One pilot valve element 27 is pressed against the valve seat 26.
[0029]
In this state, the pilot hole 25 is closed, and the pressure regulating chamber 21 communicates with the inside of the high-pressure refrigerant flow path 2 on the downstream side of the valve seat 4 via the leak path 22. The coil spring 31 is pressed against the valve seat 4 so that the refrigerant is not sent to the evaporator.
[0030]
Thus, while the solenoid 40 is in the ON state, the opening degree of the first pilot valve element 27 is controlled by the power element 10 that operates by sensing changes in the temperature and pressure of the low-pressure refrigerant sent from the outlet of the evaporator. And the flow rate of the refrigerant fed into the evaporator is controlled.
[0031]
【The invention's effect】
According to the present invention, switching between the flow rate control state corresponding to the temperature of the low-pressure refrigerant sent from the evaporator and the fully closed state can be performed with a small solenoid, which is very advantageous in terms of space and power consumption.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a forced valve closing state of an expansion valve with a solenoid valve according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view showing a state in which the forced valve closing state of the expansion valve with electromagnetic valve according to the embodiment of the present invention is released.
FIG. 3 is a partially enlarged cross-sectional view of a valve opening state in a state where a forced valve closing state of the expansion valve with electromagnetic valve according to the embodiment of the present invention is released.
FIG. 4 is a partially enlarged cross-sectional view of the valve closing state in a state where the forced valve closing state of the expansion valve with electromagnetic valve according to the embodiment of the present invention is released.
[Explanation of symbols]
2 High-pressure refrigerant flow path 3 Low-pressure refrigerant flow path 4 Valve seat 5 Valve element 10 Power element 20 Piston-like member 21 Pressure regulating chamber 22 Leakage path 25 Pilot hole 26 Valve seat 27 First pilot valve element 30 Second pilot valve element 31 Compression coil spring 40 Solenoid 41 Movable iron core 44 Compression coil spring

Claims (1)

A valve element disposed opposite to the valve seat formed in the middle of the high-pressure refrigerant flow path through which the high-pressure refrigerant toward the inlet of the evaporator passes,
A pressure regulating chamber formed so as to communicate with the high-pressure refrigerant flow path downstream from the valve seat via a leak path;
One end side passes through the valve seat so as to move together with the valve body and is connected to the valve body, and the other end side is arranged facing the pressure regulating chamber so as to receive the pressure in the pressure regulating chamber. A piston-like member;
A pilot hole having a flow passage cross-sectional area larger than the leak passage, penetrating through the piston-like member and having one end opened on the back side of the valve body and the other end opened in the pressure regulating chamber;
A first pilot hole opening / closing valve that opens and closes the pilot hole driven by a power element that operates by sensing changes in temperature and pressure of the low-pressure refrigerant delivered from the outlet of the evaporator;
An expansion valve with a solenoid valve, characterized in that a second pilot hole on-off valve that is driven by a solenoid to open and close the opening of the pilot hole on the valve element rear side is provided.

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