JPH09222268A - Expansion valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a stable operation of an expansion valve to be kept even if a pressure of high pressure refrigerant at an upstream side is varied and increased by a method wherein a biasing means for biasing a rod in a direction of right angle or an approximate right angle direction in respect to its axis is abutted against a side surface of the rod. SOLUTION: A rod 23 inserted into and passed through a through-pass hole 14 is slidably arranged in an axial direction. A push member 38 made of plastic material having a low thermal conductivity is fixed to an immovable section between a low pressure refrigerant flow passage 12 and a thermo-sensitive chamber 30 and a running-around of the low pressure refrigerant is restricted at a side of the thermo-sensitive chamber 30. Provided that the push member 38 is provided with an aeration groove 40 passed and punched for communicating between the low pressure refrigerant flow passage 12 and the thermo- sensitive chamber 30. Then, a compression spring 45 biasing the rod 23 in a direction extending in a direction which is substantially at a right angle in respect to an axial direction is arranged within the aeration groove 40 while being abutted against a side surface of the rod.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an expansion valve for adiabatically expanding a refrigerant while controlling the flow rate of the refrigerant sent to an evaporator in a refrigeration cycle.

[0002]

2. Description of the Related Art There are various types of expansion valves, but they are arranged so as to oppose to a valve seat hole formed by narrowing the high pressure refrigerant passage through which high pressure refrigerant sent to an evaporator is narrowed from the upstream side. There is widely used an expansion valve in which a valve element is arranged in the valve, and the valve element is opened / closed according to the temperature of the low-pressure refrigerant sent from the evaporator.

[0003]

The high-pressure refrigerant sent to the expansion valve may have a pressure fluctuation on the upstream side for some reason. The pressure fluctuation is transmitted to the expansion valve using the high-pressure refrigerant liquid as a medium. You.

Then, in the conventional expansion valve as described above, when the refrigerant pressure on the upstream side of the valve body rises due to pressure fluctuation, it acts in the direction of closing the valve body, so the refrigerant on the upstream side of the valve body. There is a case where the pressure further rises, the pressure fluctuation becomes larger, and the operation of the expansion valve becomes very unstable.

Accordingly, an object of the present invention is to provide an expansion valve capable of maintaining stable operation even if the pressure of the high-pressure refrigerant on the upstream side fluctuates and rises.

[0006]

In order to achieve the above object, the expansion valve of the present invention has a valve seat hole formed by narrowing the middle of a high pressure refrigerant passage through which the high pressure refrigerant sent to the evaporator passes. On the other hand, the valve body is arranged so as to oppose from the upstream side, and the temperature sensing portion that operates in response to the temperature of the low-pressure refrigerant sent from the evaporator and the valve body are loosely inserted into the valve seat. In the expansion valve in which the valve element is opened and closed by connecting with a biasing means for biasing the rod in a direction orthogonal to the axial line or an angular direction close to the axis, the side face of the rod is abutted. It is characterized by being provided.

A fulcrum portion which serves as a fulcrum for tilting the rod may be provided by supporting the rod in a position between the valve seat and the urging means in a state of being able to advance and retract in the axial direction.

In the expansion valve of the present invention, the valve body is arranged so as to oppose from the upstream side to the valve seat hole formed by narrowing the middle of the high pressure refrigerant passage through which the high pressure refrigerant sent to the evaporator passes. The valve body is arranged to connect the temperature sensing portion, which operates according to the temperature of the low-pressure refrigerant sent from the evaporator, with the valve body by a rod that is loosely inserted into the valve seat to open and close the valve body. In the expansion valve described above, the valve body is formed in a shape in which a change in the cross-sectional area of the refrigerant flow path is small as compared with the movement amount of the valve body when the valve is on the verge of being completely closed. .

[0009]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. In the figure, 1 is an evaporator, 2 is a compressor, 3 is a condenser,
Reference numeral 4 denotes a liquid receiver which is connected to the outlet side of the condenser 3 and contains a high-pressure liquid refrigerant, and 10 denotes an expansion valve, which forms a refrigeration cycle. ).

In the main body block 11 of the expansion valve 10, a low-pressure refrigerant passage 12 for passing a low-temperature low-pressure refrigerant gas sent from the evaporator 1 to the compressor 2 and a high-temperature high-pressure refrigerant liquid sent to the evaporator 1 are provided. And a high-pressure refrigerant channel 13 for adiabatically expanding the same.

The low-pressure refrigerant flow path 12 has an inlet end connected to the outlet of the evaporator 1 and an outlet connected to the inlet of the compressor 2. The high-pressure refrigerant flow path 13 has an inlet-side end connected to the outlet of the liquid receiver 4, and an outlet connected to the inlet of the evaporator 1.

The low-pressure refrigerant flow path 12 and the high-pressure refrigerant flow path 13 are formed in parallel with each other, and a through hole 14 perpendicular to this is formed.
Penetrates between the low-pressure refrigerant channel 12 and the high-pressure refrigerant channel 13. In addition, a greenhouse 30 is attached to the opening formed in the same direction as the through hole 14 so as to escape to the outside from the low-pressure refrigerant channel 12.

A valve seat hole 15 having a circular cross section is formed in the middle of the high pressure refrigerant flow path 13 in the middle of the flow path area. A spherical valve element 16 having a diameter larger than the diameter of the valve seat hole 15 is arranged facing each other from the side.

Then, the narrowest part of the gap between the valve body 16 and the inlet of the valve seat hole 15 becomes the narrowed portion of the high pressure refrigerant flow path 13, and the downstream conduit from there to the evaporator 1. Inside, the high-pressure refrigerant adiabatically expands.

The valve body 16 is biased by a compression coil spring 17 in a direction approaching the valve seat hole 15 (that is, a closing direction). Reference numeral 18 denotes an adjustment nut screwed to the main body block 11 to adjust the urging force of the compression coil spring 17, and reference numeral 19 denotes an O-ring for sealing between the high-pressure refrigerant flow path 13 and the outside.

The rod 23 inserted in the through hole 14 is
It is slidably provided in the axial direction, the upper end of which reaches the temperature sensing chamber 30, the middle part vertically passes through the low-pressure refrigerant flow path 12, passes through the through-hole 14, and the lower end is at the head of the valve body 16 Welded.

However, as in the second embodiment, a hole may be formed in the valve body 16 and the end portion of the rod 23 may be fitted therein. Note that the rod 23 is formed to be thinner than the valve seat hole 15 so that the refrigerant can pass between the wall surface of the valve seat hole 15 and the wall.

Therefore, if the valve body 16 is pushed by the rod 23 against the biasing force of the compression coil spring 17 and moves away from the valve seat hole 15, the flow passage area of the high pressure refrigerant flow passage 13 becomes large. As described above, the flow path area of the high-pressure refrigerant flow path 13 changes in accordance with the amount of movement of the rod 23, thereby changing the amount of the high-pressure refrigerant supplied to the evaporator 1.

The inner diameter of the through hole 14 is considerably thicker than the outer diameter of the rod 23, so that the rod 23 can be tilted in the through hole 14. However, the through hole 1
Only the fulcrum portion 21 formed at a very short length in the middle of 4 has a dimension in which the rod 23 can freely advance and retreat in the axial direction but hardly rattles in the radial direction. Therefore, when the rod 23 is inclined, the rod 23 is inclined with the fulcrum 21 as a fulcrum.

Reference numeral 24 is an O-ring for sealing between the high-pressure refrigerant flow path 13 and the low-pressure refrigerant flow path 12, and is arranged adjacent to the fulcrum portion 21 and in close contact with the outer peripheral surface of the rod 23. There is.

The greenhouse 30 includes a housing 31 made of a thick metal plate and a flexible thin metal plate (for example, a thickness of 0.1 mm).
It is airtightly surrounded by a diaphragm 32 made of a stainless steel plate).

A large dish-shaped diaphragm receiving plate 3 facing the central portion of the lower surface of the diaphragm 32.
3 is arranged, and the top part of the rod 23 is in contact with the central part of the lower surface thereof.

In the greenhouse 30, the coolant flow passages 12,
A gas in a saturated vapor state, which has the same or similar properties as the refrigerant flowing in the 13, is sealed therein, and the injection hole for gas filling is closed by a stopper 34. 36 is an O-ring for sealing.

A bush 38 made of a plastic material having a low thermal conductivity is fixed to a stationary portion between the low-pressure refrigerant passage 12 and the greenhouse 30 to prevent the low-pressure refrigerant from flowing into the greenhouse 30 side. It is regulated.

However, the bush 38 has a low-pressure refrigerant flow path 12
Since the ventilation groove 40 for communicating between the low pressure refrigerant and the temperature sensing chamber 30 penetrates and penetrates, the low pressure refrigerant flowing through the low pressure refrigerant flow path 12 circulates a small amount to the temperature sensing chamber 30 side through the ventilation groove 40. . As a result, the temperature of the refrigerant flowing in the low-pressure refrigerant channel 12 is transmitted to the temperature-sensitive chamber 30 slowly.

The portion extending downward from the bush 38 in the form of a mushroom stem serves as a rod guide 42 for guiding the rod 23, and the end thereof reaches close to the O-ring 24 adjacent to the fulcrum portion 21. There is.

The rod 2 is attached to the axial portion of the rod guide 42.
Although the guide hole 43 through which the through hole 3 passes is formed, the inner diameter of the guide hole 43 is substantially the same as the inner diameter of the through hole 14 so that the rod 23 can be inclined inside. I have.

In the ventilation groove 40, a compression coil spring 45 for urging the rod 23 in the vicinity of the diaphragm receiving plate 33 so as to push the rod 23 in a direction substantially perpendicular to the axial direction.
Is arranged in contact with the side surface of the rod.

As a result, as shown in FIG.
Is separated from the valve seat hole 15, the rod 23 is pressed by the compression coil spring 45 and pressed against the wall surface of the guide hole 43 at that position, so that the frictional resistance against the movement of the rod 23 in the axial direction is increased. While acting, the rod 23 is in a tilted state with the fulcrum portion 21 as a fulcrum.

In the expansion valve configured as described above,
When the temperature of the low-pressure refrigerant flowing in the low-pressure refrigerant passage 12 decreases, the temperature of the diaphragm 32 decreases, and the saturated vapor gas in the temperature-sensitive chamber 30 condenses on the inner surface of the diaphragm 32.

Then, the pressure in the greenhouse 30 is lowered and the diaphragm 32 is displaced, so that the rod 23 is pushed and moved by the compression coil spring 17, and as a result, the valve body 1 is moved.
Since 6 moves to the valve seat hole 15 side and the flow passage area of the high pressure refrigerant is narrowed, the flow rate of the refrigerant sent to the evaporator 1 is reduced.

When the temperature of the low-pressure refrigerant flowing in the low-pressure refrigerant passage 12 rises, the valve body 16 is pushed by the rod 23 and separated from the valve seat hole 15 by the operation opposite to the above, and the passage area of the high-pressure refrigerant widens. Therefore, the flow rate of the high-pressure refrigerant sent to the evaporator 1 increases.

In such an operation, in the range from the state of FIG. 1 where the valve body 16 is separated from the valve seat hole 15 to the state of FIG. 2 where the valve body 16 just touches the valve seat hole 15, the rod 23 is It moves back and forth in the axial direction while it is tilted.

Therefore, a frictional resistance based on the urging force of the compression coil spring 45 acts on the forward / backward movement of the rod 23, and the valve body 21 is not completely closed by the instantaneous pressure increase in the high pressure refrigerant flow passage 13.

As shown in FIG. 2, when the rod 23 is tilted, the valve element 16 welded to the rod 23 is not located at the center of the valve seat hole 15, so the valve is open without being closed. Therefore, in order to close the valve completely, the valve body 16
Needs to be brought to the central position of the valve seat hole 15.

Therefore, from the state shown in FIG.
6 is in close contact with the entire circumference of the valve seat hole 15 to close the valve.
In the range of shifting to the state of, the rod 23 tilts from the tilted state to the straight state around the fulcrum portion 21, so that the biasing force of the compression coil spring 45 is further increased as shown in the operating characteristics of FIG. An extra force for compressing the compression coil spring 45 against the force is required.

Therefore, when the refrigerant pressure in the high-pressure refrigerant flow path 13 rises due to the pressure fluctuation on the upstream side, it rises.
6 acts to close the valve 6, but as described above, a large force against the biasing force of the compression coil spring 45 is required to completely close the valve element 16, so that the valve element 16 closes when the pressure rises for a short time. It does not develop into a large pressure fluctuation.

FIG. 5 shows an expansion valve according to a second embodiment of the present invention, in which the valve element 16 is compared with the amount of movement of the valve element 16 when the valve is on the verge of being completely closed. It is formed in a shape that reduces the change in cross-sectional area of the flow path.

In this embodiment, the through hole 14 is formed so as to fit with the rod 23 so that the rod 23 does not incline, and the compression coil spring 45 and the elongated rod which bias the rod 23 from the side. There is no guide, etc. Reference numeral 51 is a compression coil spring for pressing the O-ring 24 for sealing.

The valve body 16 is formed in a conical shape, and the end portion of the rod 23 is fitted into the hole formed at the top of the valve body 16. The conical inclined surface of the valve element 16 is formed at an angle that is steeper than the angle of the tapered surface formed at the inlet opening of the valve seat hole 15.

At the top of the valve body 16, as shown in an enlarged view in FIG. 6, a step 5 having an outer diameter slightly smaller than the inner diameter of the valve seat hole 15 is formed.
2 is formed, and the side wall surface of the step 52 is formed in a direction parallel to the axis of the rod 23, like the inner peripheral surface of the valve seat hole 15. Further, in the range closer to the top than the step 52, the conical slope is formed at a gentler angle than the lower part.

By forming the valve element 16 in the above-described shape, in the range from the state where the valve is wide open to the state where the step 52 begins to enter the valve seat hole 15,
The amount of movement of the valve element 16 and the change in the cross-sectional area of the refrigerant channel are linear.

However, as shown in the characteristic diagram of FIG. 7, in comparison with the amount of movement of the valve body 16 in the range where the step 52 begins to enter the valve seat hole 15 and the side where the valve is closed further. As a result, the change in the cross-sectional area of the refrigerant flow path becomes very small. And in the range close to the state of being fully closed,
Further, the relationship between the amount of movement of the valve element 16 and the change in the cross-sectional area of the refrigerant channel is restored.

Therefore, even if the valve body 16 moves in the closing direction due to pressure fluctuations in the high-pressure refrigerant passage 13, the cross-sectional area of the refrigerant passage does not change much at the stage before the valve body 16 is completely closed. When the pressure rises over time, the valve does not close and does not develop into a large pressure fluctuation.

The present invention is not limited to the above-mentioned respective embodiments. For example, the shape of the valve body is not necessarily spherical in the first embodiment, and the second embodiment is not necessary. The shape does not necessarily have to be conical.

[0046]

According to the present invention, the urging means for urging the rod connected to the valve body in the direction perpendicular to the axis of the rod or in the angular direction close to the axis is provided in contact with the side surface of the rod. In addition, the rod is tilted about the position between the valve seat and the biasing means as a fulcrum, so that in order to close the valve, the frictional force and the biasing force itself exerted by the biasing means are counteracted. Therefore, even if the pressure in the high-pressure refrigerant flow path rises for a short time due to the pressure fluctuation of the refrigerant, the valve does not close and the pressure does not greatly fluctuate. Therefore, the pressure fluctuation in the refrigerant channel is immediately stabilized, and the expansion valve can maintain a stable operation.

Further, the connecting portion between the valve body and the rod is formed in a shape in which the change in the cross-sectional area of the refrigerant passage is smaller than the moving amount of the valve body when the valve is almost closed. , Even if the valve body moves in the closing direction due to pressure fluctuations in the high-pressure refrigerant flow path, the cross-sectional area of the flow path does not change so much. Does not close and does not develop into large pressure fluctuations.
Therefore, the pressure fluctuation in the refrigerant channel is immediately stabilized, and the expansion valve can maintain a stable operation.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an expansion valve according to a first embodiment of the present invention in a state where a valve is largely opened.

FIG. 2 is a vertical cross-sectional view of the expansion valve according to the first embodiment of the present invention with the valve being slightly open.

FIG. 3 is a vertical sectional view of the expansion valve according to the first embodiment of the present invention in a state where the valve is completely closed.

FIG. 4 is a characteristic diagram of the expansion valve according to the first embodiment of the present invention.

FIG. 5 is a vertical sectional view of an expansion valve according to a second embodiment of the present invention.

FIG. 6 is a partial enlarged cross-sectional view showing a moving state of the expansion valve according to the second embodiment of the present invention.

FIG. 7 is a characteristic diagram of an expansion valve according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Evaporator 10 Expansion Valve 12 Low Pressure Refrigerant Flow Path 13 High Pressure Refrigerant Flow Path 15 Valve Seat Hole 16 Valve Body 21 Support Point 23 Rod 30 Greenhouse 45 Compression Coil Spring 52 Step

Claims (3)

[Claims] 1. A valve body is arranged so as to oppose from a upstream side to a valve seat hole formed by narrowing the middle of a high-pressure refrigerant passage through which high-pressure refrigerant sent to an evaporator passes, and the evaporator is provided. In an expansion valve configured to open and close the valve body by connecting the temperature sensing portion that operates in response to the temperature of the low-pressure refrigerant sent out and the valve body with a rod that is loosely inserted into the valve seat, An expansion valve, characterized in that a biasing means for biasing the rod in a direction at right angles to the axis thereof or in an angular direction close to the right angle is provided in contact with the side surface of the rod. 2. A fulcrum portion serving as a fulcrum for supporting the rod in a position between the valve seat and the urging means so as to be axially movable back and forth, and serving as a fulcrum for tilting the rod. Expansion valve described. 3. A valve body is arranged so as to oppose from a upstream side to a valve seat hole formed by narrowing a high-pressure refrigerant passage through which a high-pressure refrigerant sent to an evaporator passes, and a valve body is arranged from the evaporator. In an expansion valve configured to open and close the valve body by connecting a temperature-sensing portion that operates in response to the temperature of the low-pressure refrigerant sent out and the valve body with a rod that is loosely inserted into the valve seat, An expansion valve, wherein the valve body is formed in a shape in which a change in cross-sectional area of the refrigerant flow path is smaller than a movement amount of the valve body when the valve is in a state of being almost closed.