JP3782896B2 - Supercooling control type expansion valve - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a supercooling degree control type expansion valve used during a refrigeration cycle.
[0002]
[Prior art]
As an expansion valve used in the refrigeration cycle, a so-called temperature-type expansion valve that controls the flow rate of the refrigerant entering the evaporator in accordance with the temperature and pressure of the low-pressure refrigerant discharged from the evaporator is widely used.
[0003]
On the other hand, the supercooling degree control type expansion valve that detects the degree of supercooling of the high-pressure refrigerant before it is sent to the evaporator and controls the flow rate of the refrigerant entering the evaporator, handles all at the inlet side of the evaporator. Therefore, there is an advantage that the apparatus can be configured very compactly.
[0004]
FIG. 6 shows such a conventional supercooling degree control type expansion valve, and a throttle portion formed in the main body block 1 by narrowing the middle of the refrigerant flow paths 2 and 3 through which the refrigerant sent to the evaporator passes. The valve body 5 is arranged so as to be capable of moving forward and backward from the upstream side.
[0005]
Then, the position of the valve body 5 is controlled by a diaphragm 11 that detects and displaces the degree of supercooling of the refrigerant upstream from the throttle unit 4, and the high-pressure refrigerant is adiabatically expanded in a state where the degree of supercooling is constant, thereby evaporating the evaporator. It sends out toward the.
[0006]
The diaphragm 11 constitutes a wall surface of the power element 10 in which condensable gas is sealed, and the outer wall surface of the power element 10 is surrounded by a heat insulating material 20 so as to be thermally shielded from outside air.
[0007]
At the head of the valve body 5, there is disposed a diaphragm receiving plate 6 that abuts against the back surface of the diaphragm 11, and the valve body 5 is biased by a compression coil spring 8 through a small diameter rod 9 from the opposite side. Has been.
[0008]
[Problems to be solved by the invention]
The valve body 5 includes a pressure in the power element 10 that fluctuates depending on the temperature of the high-pressure refrigerant in the refrigerant flow path 2 upstream from the throttle portion 4, a refrigerant pressure in the refrigerant flow path 2, and a biasing force of the compression coil spring 8. However, it is necessary to fit the valve body receiver 7 formed in the main body block 1 without backlash so as not to vibrate due to the refrigerant flow.
[0009]
Therefore, the amount of high-pressure refrigerant passing through the narrow fitting portion between the valve body 5 and the valve body receiver 7 is extremely small, and the refrigerant temperature in the refrigerant flow path 2 is mainly reduced by the heat conduction through the valve body 5 as a diaphragm. 11 is transmitted. As a result, there has been a drawback that the displacement of the valve body 5 is delayed with respect to the temperature change of the high-pressure refrigerant.
[0010]
Accordingly, an object of the present invention is to provide a supercooling degree control type expansion valve that has good responsiveness to temperature changes of a high-pressure refrigerant.
[0011]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the supercooling degree control type expansion valve of the present invention is opposed to the throttle portion formed by narrowing the middle of the high-pressure refrigerant flow path through which the refrigerant sent to the evaporator passes, and on the upstream side thereof. The valve body is disposed so as to be freely movable back and forth, and the position of the valve body is controlled by a diaphragm that detects and displaces the supercooling degree of the refrigerant on the upstream side of the throttling portion, so that the supercooling degree of the high-pressure refrigerant is kept constant. In the supercooling degree control type expansion valve which is adiabatically expanded in a state to be sent out toward the evaporator, the valve body is formed with a backlash fitting in which the valve body fits in the forward / backward direction, and the valve A refrigerant passage is formed in the fitting outer peripheral surface of the body with the valve body receiver so that the high-pressure refrigerant on the upstream side of the throttle portion is guided to the vicinity of the diaphragm surface.
[0012]
In addition, the said valve body receptacle may be provided adjacent to the said throttle part, and the high pressure refrigerant | coolant which passed the said diaphragm surface vicinity may be guide | induced to the said throttle part through the said refrigerant passage.
[0013]
Moreover, the outer periphery of the part which protruded from the said valve body receptacle of the said valve body to the upstream may be formed in the shape narrowly bound.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a supercooling degree control type expansion valve according to a first embodiment of the present invention, and a refrigerant flow path formed in a main body block 1 so as to pass a refrigerant fed into an evaporator (not shown). A narrowed portion 4 is formed by narrowing the middle of 2 and 3. Reference numeral 2 is a pipe line on the upstream side of the throttle portion 4, and 3 is a pipe line on the downstream side.
[0015]
A valve body 5 is disposed so as to face the throttle portion 4 from the upstream side and to be movable back and forth in the same direction as the axis of the throttle portion 4. The valve body 5 is fitted to a valve body receiver 7 formed in the main body block 1 adjacent to the upstream side of the throttle portion 4 so that there is no backlash, and the tip portion facing the throttle portion 4 has a tapered surface. Is formed.
[0016]
However, as shown in FIG. 2 showing an AA cross section, a plurality of refrigerant passages 5a having a cross-sectional shape recessed in a groove shape are formed on the fitting outer peripheral surface of the valve body 5 with the valve body receiver 7. The high-pressure refrigerant that is formed in the parallel direction and upstream from the throttle unit 4 is guided to the throttle unit 4 through the refrigerant passage 5a.
[0017]
Returning to FIG. 1, the diaphragm receiving plate 6 with which the other end of the valve body 5 abuts is formed in a thin and wide shape with a metal material having good thermal conductivity, and the opposite surface of the diaphragm receiving plate 6 is the power. It is in contact with the back surface of the diaphragm 11 of the element 10.
[0018]
The power element 10 is formed by a diaphragm 11 having a wall surface in contact with the diaphragm receiving plate 6 made of a flexible thin film, and other portions are surrounded by a metal housing 12 in a sealed state.
[0019]
In the pressure chamber 13 of the power element 10, a condensable gas and inert nitrogen gas having characteristics similar to those of the refrigerant flowing in the refrigerant flow paths 2 and 3 are sealed, and the outer surface of the housing 12 is It is surrounded by a heat insulating material 20 so as to be thermally shielded from outside air.
[0020]
The valve body 5 is urged toward the diaphragm 11 side by a compression coil spring 8 disposed on the downstream side of the throttle portion 4 via a small diameter rod 9 passed through the throttle portion 4. At a position where the pressure in the pressure chamber 13 received from the refrigerant, the refrigerant pressure in the refrigerant flow path 2 upstream of the throttle portion 4, and the biasing force received from the compression coil spring 8 are balanced.
[0021]
The urging force of the compression coil spring 8 can be adjusted by changing the tightening amount of the screwed specimen 19 provided by being screwed to the main body block 1 while receiving the other end side of the compression coil spring 8.
[0022]
The attachment screwing portion of the housing 12 of the power element 10 to the main body block 1 is formed to have a thickness that allows a sufficient gap between the outer peripheral surface of the valve body 5. As a result, a part of the high-pressure refrigerant in the refrigerant flow path 2 on the upstream side of the throttle unit 4 reaches the throttle unit 4 after directly contacting the diaphragm receiving plate 6 and passing through the refrigerant passage 5a.
[0023]
Therefore, the pressure in the space on the back surface of the diaphragm 11 is always the same as the pressure of the high-pressure refrigerant in the refrigerant flow path 2. Further, the temperature of the refrigerant in the refrigerant flow path 2 is transmitted to the back surface of the diaphragm 11 through the diaphragm receiving plate 6 in a very short time, and the pressure in the pressure chamber 13 changes correspondingly. As a result, the diaphragm 11 is displaced corresponding to the degree of supercooling of the refrigerant upstream of the throttle 4, thereby controlling the position of the valve body 5.
[0024]
In this way, the flow rate of the refrigerant is controlled promptly without delaying the reaction with respect to the temperature change of the high-pressure refrigerant sent into the refrigerant flow path 2, and the high-pressure in the refrigerant flow path 2 upstream from the throttle portion 4. In a state where the degree of supercooling of the refrigerant is kept constant, the refrigerant is sent to the evaporator while adiabatically expanding on the downstream side of the throttle unit 4.
[0025]
In addition, this invention is not limited to the said embodiment, For example, as FIG. 3 which shows the AA cross section, the refrigerant | coolant passage 5a makes the valve body 5 polygonal cross-sectional shape etc. Can also be formed.
[0026]
In addition, as shown in FIG. 4, if the outer periphery of the intermediate portion of the valve body 5 (the portion in the refrigerant flow path 2 protruding upstream from the valve body receiver 7) is formed in a narrow and narrow shape, the refrigerant The flow of the refrigerant toward the refrigerant passage 5a and the flow of the refrigerant toward the diaphragm receiving plate 6 in the flow path 2 can be made smoother.
[0027]
Further, as shown in FIG. 5, even when the valve body receiver 7 is formed between the refrigerant flow path 2 and the power element 10 as in the conventional case, the outer peripheral fitting surface of the valve body 5 is formed. By forming the refrigerant passage 5a, the high-pressure refrigerant in the refrigerant flow path 2 directly touches the back surface of the diaphragm receiving plate 6, so that the reaction delay of the valve operation can be eliminated to some extent.
[0028]
【The invention's effect】
According to the present invention, the refrigerant passage is formed in the fitting surface between the valve body receiver and the valve body in which the valve body is fitted without looseness, and the high-pressure refrigerant upstream from the throttle portion is guided to the vicinity of the diaphragm surface. By doing so, the diaphragm can be quickly displaced in response to the temperature change of the high-pressure refrigerant, and the flow rate control in a state where the degree of supercooling of the high-pressure refrigerant is made constant can be performed with quick responsiveness.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a supercooling degree control type expansion valve according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA of the first embodiment of the present invention.
FIG. 3 is an AA sectional view of a second embodiment of the present invention.
FIG. 4 is a longitudinal sectional view of a supercooling degree control type expansion valve according to a third embodiment of the present invention.
FIG. 5 is a longitudinal sectional view of a supercooling degree control type expansion valve according to a fourth embodiment of the present invention.
FIG. 6 is a longitudinal sectional view of a conventional supercooling degree control type expansion valve.
[Explanation of symbols]
2, 3 Refrigerant flow path 4 Throttle part 5 Valve body 5a Refrigerant passage 6 Diaphragm receiving plate 7 Valve body receiver 10 Power element 11 Diaphragm 13 Pressure chamber

Claims (3)

A valve element is arranged on the upstream side of the throttle portion formed by narrowing the middle of the high-pressure refrigerant flow path through which the refrigerant sent to the evaporator passes, and the upstream side of the throttle portion. A supercooling degree in which the position of the valve body is controlled by a diaphragm that detects and displaces the cooling degree, and the high-pressure refrigerant is adiabatically expanded in a state where the supercooling degree is constant and is sent out toward the evaporator. In the control type expansion valve,
The valve body forms a valve body receiver that fits in the forward / backward direction without backlash, forms a refrigerant passage on the outer peripheral surface of the valve body and the valve body receiver, and is upstream of the throttle portion. The supercooling degree control type expansion valve, wherein the high-pressure refrigerant is guided to the vicinity of the diaphragm surface. 2. The supercooling degree control according to claim 1, wherein the valve body receiver is provided adjacent to the throttle portion, and the high-pressure refrigerant that has passed near the diaphragm surface is guided to the throttle portion through the refrigerant passage. Expansion valve. The supercooling degree control type expansion valve according to claim 2, wherein an outer periphery of a portion of the valve body that protrudes upstream from the valve body receiver is formed in a narrowed shape.

Images