JPH02254270A - Temperature actuating type expansion valve - Google Patents

Abstract

PURPOSE:To enable an external equalizing type flow rate control with accuracy regardless of any factors, such as a diaphragm or an equivalent valve diameter by making a first seal section equivalent to a second sealing section in diameter and reducing the diameter of a rod compared with a valve disk. CONSTITUTION:The diameter of a second seal section 19 is almost identical to that of a first seal section 16. An area covered with the second seal section 19 is identical to that covered with the first seal section 16. A long and narrow rod 35 is installed between a wear plate 34 and a valve disk 15 in an axial direction so that it may move forward and backward freely. The diameter of this rod 35 is smaller than an effective diameter of a diaphragm 23 and far smaller than the diameter of the valve disk 15. It is, therefore, possible to carry out a perfect external equalizing type flow rate control, thereby controlling the flow rate of refrigerant accurately even if attempts are made to reduce the size of the diaphragm which is used as a drive means and make compact the size of a device and increase the diameter of the valve disk 15 and a refrigerating capacity.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a temperature-operated system that automatically adjusts the amount of high-pressure refrigerant when it is expanded and sent to an evaporator in refrigeration equipment, air-conditioning equipment, etc. Regarding expansion valves.

The amount of refrigerant sent from the expansion valve to the evaporator must always match the amount of refrigerant evaporated in the evaporator. In other words, the flow rate of the refrigerant in *excellence is immediately equal to the state of the refrigerant at the exit side of the evaporator. There are two types of temperature-activated expansion valves used for such control: external pressure equalization type and internal pressure equalization type.

The externally pressure-equalized, temperature-activated expansion valve precisely controls the flow rate of refrigerant within the expansion valve based on the pressure of the refrigerant exiting the evaporator and its temperature. In contrast, an internally equalized temperature-activated expansion valve controls the flow rate of refrigerant based on the pressure of refrigerant entering the evaporator and the temperature of refrigerant exiting the evaporator. In the internal pressure equalization type, the pressure on the outlet side of the evaporator is estimated from the pressure on the inlet side of the evaporator to control the flow rate.

Therefore, the internal pressure equalization type expansion valve has the disadvantage that the control of the flow rate of the refrigerant becomes inaccurate due to changes in the state of the evaporator, etc., and is therefore used in refrigeration equipment and the like where the operating state does not fluctuate much. On the other hand, since air conditioners for automobiles and the like have large fluctuations in operating conditions, accurate control cannot be performed using an internal pressure equalization type expansion valve, and it is necessary to use an external pressure equalization type expansion valve.

In such a temperature-activated expansion valve, the temperature change of the refrigerant exiting the evaporator is usually converted into a pressure change, and the pressure change drives a diaphragm, which in turn drives a valve for regulating the flow rate of the refrigerant. ing. In the past, diaphragms were used that had a very large diameter relative to the effective diameter of the valve.

However, such expansion valves have progressively reduced the diameter of the diaphragm because the diaphragm takes up too much space. And on the contrary.

In order to improve the cooling capacity, it is necessary to increase the flow rate of refrigerant, so the effective diameter of the valve has been gradually increased. However, as the effective diameter of the diaphragm becomes smaller compared to the effective diameter of the valve, the pressure of the refrigerant within the expansion valve has a greater influence on the control of the operation of the valve. Therefore, in order to accurately control the refrigerant flow rate, it is necessary to create a structure in which the refrigerant pressure within the expansion valve does not act on the valve as much as possible.

[Prior Art] FIG. 10 shows a conventional external pressure-equalizing temperature-operated expansion valve 10.
It shows 0. 200 is an evaporator. Low pressure chamber 10 of diaphragm chamber 102 partitioned by diaphragm 101
3 communicates with the outlet side of the evaporator 200, and the high pressure chamber 10
4 is a temperature sensing section 105 provided on the outlet side of the evaporator 200;
The capillary tube 10B is connected to the capillary tube 10B, and a refrigerant is sealed inside the capillary tube 10B. 107 is a flow path on the inlet side for high-pressure refrigerant, 108 is a flow path on the outlet side for expanded and low-pressure refrigerant, and valve 1 opens and closes between the two flow paths 107 and 108.
09 is driven forward and backward in the axial direction by the diaphragm 101 via the rod 110.

Then, the effective diameter d1 of the valve 109 and the diameter d of the rod 110
The size is set to be the same as that of 2. Therefore, the pressure p1 of the high-pressure refrigerant acts equally in the opening direction and the closing direction of the valve 109, and the forces in both directions cancel each other out.
1 does not affect the opening/closing operation of the valve 109.

[Problem II to be Solved by the Invention] However, in the expansion valve 100 shown in FIG. from the low pressure chamber 103 side. Therefore, if the pressure p2 in the outlet side flow path 108 is the pressure p2 in the low pressure chamber 103,
If equal to o, the diaphragm 101 operates correctly. That is, the pressure within the expansion valve has no effect on flow control.

However, as described above, the pressure po in the low pressure chamber 103 is the same as the pressure of the refrigerant on the outlet side of the evaporator 200, whereas the pressure p2 in the outlet side flow path 108 is the same as the pressure of the refrigerant on the outlet side of the evaporator 200.
It is almost the same as the refrigerant pressure on the inlet side. In other words, although the low pressure chamber 103 of the diaphragm chamber 102 adopts an external pressure equalization type and communicates with the outlet side of the evaporator 200, the diaphragm lO1 has a cross-sectional area of the rod 110 on the inlet side of the evaporator 200. In response to the pressure p2, the internal pressure is equalized.

In this way, with conventional temperature-activated expansion valves, when trying to downsize the diaphragm and obtain a large flow rate, the structure that originally had an external pressure equalization type changed to an internal pressure equalization type, making it suitable for use in automobiles with large fluctuations in operating conditions. Air conditioners and the like have the disadvantage that the flow rate of refrigerant cannot be accurately controlled.

This invention eliminates such drawbacks of the prior art.

It is an object of the present invention to provide a temperature-activated expansion valve that can perform external pressure-equalizing accurate flow rate control regardless of the effective diameter of the diaphragm or valve.

[Means for Solving the Problems] In order to achieve the above object, the temperature-operated expansion valve of the present invention has a flow rate adjustment chamber formed in a casing to adjust the flow rate of the refrigerant, and a flow rate adjustment chamber for allowing the refrigerant to pass through. A through hole is bored in the axial direction, and the valve body is arranged in the flow rate adjustment chamber so as to be able to move back and forth in the axial direction, and the valve body is opened toward the side surface of the valve body at one end side of the valve body. A first refrigerant flow path that is connected to the flow rate adjustment chamber, a second refrigerant flow path that communicates with the through hole on the other end side of the valve body, and a second refrigerant flow path that communicates with the through hole on the other end side of the valve body; a first seal portion for sealing between the refrigerant flow path and the second refrigerant flow path; and a first seal portion for sealing between the refrigerant flow path and the second refrigerant flow path; a second seal part formed to have approximately the same diameter as the first seal part, and a second seal part formed thinner than the valve body to drive the valve body in its axial direction; A drive that operates based on the pressure of the refrigerant gas exiting the evaporator and the temperature of the refrigerant gas to drive the rod in the axial direction. It is characterized by having a means.

Further, a flow rate adjustment chamber is formed in the casing to adjust the flow rate of the refrigerant, and a through hole for passing the refrigerant is bored in the axial direction, and the flow rate adjustment chamber is arranged so as to be movable forward and backward in the axial direction. a first refrigerant flow path connected to the flow rate adjustment chamber so as to open toward a side surface of the valve body at one end side of the valve body; a second refrigerant flow path communicating with the flow rate adjustment chamber and the through hole; and a first seal for sealing between the flow rate adjustment chamber and the second refrigerant flow path on the other end side of the valve body. and a second seal portion formed to have approximately the same diameter as the first seal portion in order to seal between the through hole and the first refrigerant flow path at the edge of the one end side of the valve body. The seal part of
An elongated rod that is thinner than the valve body and is provided to move forward and backward along the axial direction of the valve body in order to drive the valve body in the axial direction, and the pressure of the refrigerant gas exiting the evaporator and the refrigerant. a driving means that operates based on the temperature of the gas to drive the rod in the axial direction, and the driving means drives the valve body forward and backward in the axial direction via the rod, It is characterized in that both the first and wS2 seal parts can be opened and closed.

[Effect]

Since the first seal part and the second seal part are formed to have approximately the same diameter, the pressure difference in the first refrigerant flow path and the pressure in the second refrigerant flow path is small relative to the valve body. It acts equally in directions opposite to the axial direction. Therefore, the valve body is not affected by the pressure difference between the refrigerants in the first and second refrigerant flow paths.

In addition, the pressure in the second refrigerant flow path affects the operation of the drive means through the rod, but the degree of influence is proportional to the square of the diameter of the rod, and the rod is formed thinner than the valve body. Therefore, the degree of impact is very small compared to the past.

In this way, the influence of the pressure in the first and second refrigerant flow paths is reduced, and the operation of the valve body, that is, the opening and closing operation of the expansion valve, is controlled by the pressure of the refrigerant gas exiting the evaporator and the temperature of the refrigerant gas. controlled by drive means which actuate in accordance with the

[Example] Examples will be described with reference to the drawings.

FIG. 1 shows a first embodiment of the invention.

In the figure, ■ is an evaporator, 2 is a compressor, 3 is a condenser, 4 is a liquid container containing high-pressure liquid refrigerant, and 10 is an expansion valve.

The casing 11 of the expansion valve 10 includes a high-pressure refrigerant flow path 12 (first refrigerant flow path) connected to the outlet of the liquid container 4 and a low-pressure refrigerant flow path 13 (first refrigerant flow path) connected to the inlet of the evaporator 1. A second refrigerant flow path) is formed. 14 is a flow rate adjustment chamber formed in the casing 11 in order to adjust the flow rate of the refrigerant flowing from the high pressure side refrigerant flow path 12 to the low pressure side refrigerant flow path 13; room 14
The low pressure side refrigerant flow path 13 is connected to the lower end side of the flow rate adjustment chamber 14 .

A substantially cylindrical valve body 15 is disposed within the flow rate adjustment chamber 14 so as to be movable forward and backward in its axial direction, that is, in the vertical direction. The valve body 15 is fitted into a sill-shaped part at the lower part of the flow rate adjustment chamber 14 with a very small clearance, and the fitting part 16 extends from the high-pressure side refrigerant flow path 12 to the low-pressure side along the outer periphery of the valve body 15. It serves as a first seal portion that seals the refrigerant flow path 13 to prevent the refrigerant from flowing.

Note that in this embodiment, the casing 11 and the valve body 15
Both are made of metal. However, casing 11 and valve body 1
5 and 5 may be made of synthetic resin. In that case, it is preferable to use a synthetic resin material with the same coefficient of thermal expansion. If so, even if there is a temperature change in the expansion valve lO, the gap between the fitting part 16 will be reduced. does not change.

Furthermore, if the surface of the valve body 15 is coated with fluororesin, the surface frictional resistance will be reduced, so the valve body 15 will be able to slide smoothly in the axial direction even when there is almost no clearance in the fitting part 16. can.

The inside of the cylindrical valve body 15 is a through hole 17 through which the refrigerant passes. Further, the upper end peripheral edge of the valve body 15 is in close contact with the bottom surface of the plug body 8 screwed into the casing 11 from above, and forms a second seal that seals between the high pressure side refrigerant flow path 12 and the through hole 17. It is part 19. Note that the plug body 18 may be fixed to the casing 11 by press fitting or other means. The diameter of the seal portion 19 is approximately the same as the diameter of the first seal portion 16,
The area of the portion of W42 surrounded by the seal portion 19 is approximately the same as the area of the portion surrounded by the first seal portion 16. 40 is the 0 ring.

Further, a pair of spring receivers 20, 21, one of which is fixed to the lower end of the valve body 15, and the other of which is screwed and fixed to the lower part of the casing 11. And both spring receivers 20.2
A coil spring 22 is compressed and installed between the valves 1 and 1, and its spring force pushes the valve body 15 upward to close the second seal portion 19.

On the other hand, the high-pressure side refrigerant flow path 12 opens toward the side surface of the valve body 15 at the upper end side of the valve body 15, and the low-pressure side refrigerant flow path 13
is in constant communication with the through hole 17 at the lower end side of the valve body 15. Therefore, in the state shown in FIG.
moves downward, the second seal portion 19 opens and the refrigerant flows from the high-pressure side refrigerant flow path 12 through the through hole 17 and into the low-pressure side refrigerant flow path 13.

A diaphragm chamber partitioned by a diaphragm 23 into an upper high pressure chamber 24 and a lower low pressure chamber 25 is formed at the upper end of the stopper 18 . The effective diameter of the diaphragm 23 is, for example, about 1.5 to 3 times the diameter of the valve body 15.

The diaphragm 23 is a thin membrane plate that is freely displaceable in its surface direction (that is, in the vertical direction), and its peripheral edge is airtightly clamped and fixed between the stopper 18 and the housing 27. The high pressure chamber 24 side is connected by a capillary tube 29 to a known temperature sensing section 28 provided on the outlet side of the evaporator l. A refrigerant is sealed inside the capillary tube 29.

On the other hand, the low pressure chamber 25 communicates with the outlet side of the evaporator l via a communication path 32. Therefore, inside the low pressure chamber 25,
The pressure is always equal to the pressure on the outlet side of the evaporator L. As a result, no pressure difference occurs between the high pressure chamber 24 and the low pressure chamber 25 until the refrigerant gas at the outlet of the evaporator 1 reaches saturated vapor, and when the refrigerant gas at the outlet of the evaporator 1 becomes superheated vapor, the pressure increases. The pressure in the chamber 24 becomes higher than the pressure in the low pressure chamber 25, and the diaphragm 23 is pushed down toward the low pressure chamber 25 (ie, downward).

A plate 34 is provided in contact with the lower surface of the diaphragm 23, and an elongated rod 35 is provided between the plate 34 and the valve body 15 so as to be movable in the axial direction. The diameter of this rod 35 is thinner than the effective diameter of the diaphragm 23 and is sufficiently thinner than the diameter of the valve body 15.
In this embodiment, the diameter of the rod 35 is 3 minutes smaller than the diameter of the valve body 15, and the cross-sectional area of the rod 35 is compared to the inner area (i.e., pressure receiving area) of the diameter of the valve body 15. It is about 1/10th of that.

The lower end of the rod 35 is in contact with a stay 20a formed inward from the spring receiver 20, as shown in Figure PI42. The rod 35 passes through a hole formed in the plug body 18 with its axis aligned with the valve body 15, and the upper end of the rod 35 is in contact with the plate 34.

Therefore, when the diaphragm 23 is pushed down due to the pressure difference between the high pressure chamber 24 and the low pressure chamber 25, the valve body 15 is pushed down via the rod 35, and the second seal portion 19 is opened, as shown in FIG. Then, the refrigerant flows from the high-pressure side refrigerant flow path 12 into the through hole 17 and is sent into the low-pressure side refrigerant flow path 13. Then, the valve body 15 comes to rest at a position where the coil spring 22 is compressed and the pressure difference between the high pressure chamber 24 and the low pressure chamber 25 balances the repulsive force of the coil spring 22.

In the embodiment configured in this way, the pressure of the high-pressure refrigerant in the high-pressure side refrigerant flow path 12 is set to PI, and the pressure of the high-pressure refrigerant in the low-pressure side refrigerant flow path 13 is set to PI.
The pressure of the low-pressure refrigerant inside is P2, the area of the part surrounded by the first seal part 16 is 51, and the area of the part surrounded by the second seal part 19 is P2.
If the inner area of the part surrounded by is S2, then the force F acting on the valve body 15 in the axial direction due to Pl and P2 is F
-(P+-P2)X (S+-52).

And S L! Since f S 2, it is F'40.

Both P and P2 hardly act on the valve body 15, and since the lower end of the rod 35 is inside the second seal portion 19, the diaphragm 23 has no effect on the diaphragm 23.

The pressure PI of the high-pressure refrigerant in the high-pressure side refrigerant flow path 12 has no effect at all.However, the pressure P2 of the low-pressure refrigerant in the low-pressure side refrigerant flow path 13 is increased by the cross-sectional area of the rod 35 on the diaphragm 2.
It acts on 3. However, the diameter of the rod 35 is sufficiently thin compared to the effective diameter of the diaphragm 23 and the diameter of the valve body 15, and the influence of P2 on the diaphragm 23 is proportional to the cross-sectional area of the rod 35 (i.e., 2 (proportional to the second power), so its influence is extremely small.

In this embodiment, the cross-sectional area of the rod 35 is set to about 1/10 of the pressure-receiving area of the valve body 15, but as long as the strength allows, the thinner the rod 35 is, the more the diaphragm 23
By making the diameter of the rod 35 one-fifth of the diameter of the valve body 15, the influence of P2 on P2 can be reduced.
The impact will be 1/25th. However, for example, rod 35
Even if the diameter of the rod is reduced to half the diameter of the valve body 15, the influence of P2 on the diaphragm 23 can be reduced to one-fourth of that in the past when the rod and the valve body had the same diameter, resulting in a clear effect. can be obtained.

[Second Embodiment] FIG. 4 shows a second embodiment of the present invention, in which a packing 16a is attached to the first seal portion 16.

Thereby, the sealing performance of the first seal portion 16 becomes perfect. In addition, the upper end of the valve body 55 is formed slightly thicker so that the diameter of the second seal portion 19 is equal to that of the first seal portion 16.
perfectly matches the diameter of As a result, the influence of the pressure of the refrigerant within the expansion valve on the movement of the valve body 55 is further reduced. The other parts are the same as the embodiment shown in FIG. However, the valve body 55 and the casing 11 are made of the same synthetic resin material. Of course, it may be made of metal.

[Embodiment of :53] FIG. 5 shows a third embodiment of the present invention, in which the rod 3
A stay 55a that comes into contact with the lower end of the valve body 55 is formed on the upper part of the valve body 55. In this way, the force transmission portion between the rod 35 and the valve body 55 may be provided anywhere.

[Fourth Embodiment] FIG. 6 shows a fourth embodiment of the present invention, in which the refrigerant flow path is arranged in the opposite manner to the embodiments shown in FIGS. 1 to 5. That is, 61 is the casing, 62 is the evaporator 1
A low-pressure side refrigerant flow path (first refrigerant flow path) connected to the inlet of
. 63 is a high-pressure side refrigerant flow path (piS2 refrigerant flow path) connected to a high-pressure refrigerant liquid container.In this way, in the temperature-operated expansion valve of the present invention, the high-pressure side refrigerant wave path and the low-pressure side refrigerant There is no problem even if the flow path is connected in reverse.

In this embodiment, the pressure PI of the high-pressure refrigerant acts on the gap between the rod 35 and the stopper 68.

A packing 68a is attached around the rod 35. 6
8b is a donut-shaped presser plate that presses the gasket 138a. In addition, the diameter of the second seal portion 69 is made slightly larger than the diameter of the first seal portion 66 so that the high pressure side pressure P1 does not affect the upper diaphragm (not shown) via the rod 35. be. That is, the inner area surrounded by the second seal part 69 is the same as the area obtained by adding the cross-sectional area of the rod 35 to the inner area surrounded by the first seal part 66.

Further, the gasket 86a of the first seal portion 66 is attached to the valve body 65.
It is attached to the side and can be easily assembled. 66b is a donut-shaped presser plate that presses the gasket 66a. In FIG. 6, 61 is a casing, 64 is a flow rate adjustment chamber, 67 is a through hole, and other parts are the same as the embodiment shown in FIG.

[Fifth example] FIG. 7 shows a fifth embodiment of the invention.

In the figure, 1 is an evaporator, 2 is a compressor, 3 is a condenser, 4 is a liquid container containing high-pressure liquid refrigerant, and 70 is an expansion valve.

In this embodiment, the expansion valve 70 is housed within a block 90 in which a refrigerant flow path is formed. 72 is a low-pressure side refrigerant flow path (first refrigerant flow path) connected to the inlet of the evaporator 1, and 73 is a high-pressure side refrigerant flow path (second refrigerant flow path) connected to the outlet of the liquid container 4. 91 is a refrigerant flow path connecting the outlet of the evaporator l and the inlet of the pressure lit machine 2.

The casing 71 of the expansion valve 70 is housed within the block 9°. 74 is for adjusting the amount of cold tofu flowing from the high pressure side refrigerant flow path 73 to the low pressure side refrigerant flow path 72,
This is a flow rate adjustment chamber formed in the casing 71, and the low pressure side refrigerant flow path 72 is connected to the side of the fIt amount adjustment chamber 74, and the high pressure side refrigerant flow path 73 is connected to the lower m side of the flow rate adjustment chamber 74. It is connected.

ti, a valve body 75 is located in the amount adjustment chamber 74 in its axial direction,
That is, it is arranged so as to be able to move forward and backward in the vertical direction.

As shown in FIG. 8, the valve body 75 has an inner cylinder 75a having a flange-shaped portion projecting outward in a tapered shape on the lower end side.
and an outer cylinder 75b press-fitted to the outer periphery of the upper end thereof.
It is formed by.

A through hole 77 is formed through the inner cylinder 75a in the axial direction. Reference numeral 80 denotes a stay with which the lower end of the rod 95 comes into contact, and is formed integrally with the inner cylinder 75a at the upper end of the inner cylinder 75a.

Returning to FIG. 7, the inner cylinder 75a is urged from below by a compression coil spring 82, and the tapered surface of the inner cylinder 75a is in contact with a circular valve seat formed in the casing 71. Reference numeral 76 indicates a contact portion thereof, and this contact portion 76 serves as a first seal portion that prevents the refrigerant from flowing into the flow rate adjustment chamber 74 from the high-pressure side refrigerant flow path 73 .

The outer diameter of the outer cylinder 75b of the valve body 75 is equal to the seal portion 7 of 'PJl.
6 diameter and approximately concave diameter (strictly speaking, the first seal part 7
The diameter is slightly smaller than 6. Casing 7
1, a plug 78 is press-fitted from above in an airtight manner, and the upper end peripheral edge of the outer cylinder 75b is in contact with the tapered portion formed on the bottom surface of the plug 78. This ′J-j contact portion 79 serves as a second seal portion that seals between the through hole 77 and the low-pressure side cold slave flow path 72 .

Note that the first seal portion 76 and the second seal portion 79 must be closed at the same time.

Therefore, when press-fitting the inner cylinder 75a into the outer cylinder 75b, as shown in FIG.
(in other words, the second seal part 79 is closed), insert the inner ft, 75a from below into the first
Push up strongly until the seal portion 76 of the connector is closed.

With this, it is possible to easily form 41i so that the first seal portion 76 and the seal portion 79 of tJIJ2 are closed simultaneously.

A spring receiver 81 is screwed and fixed to the lower part of the casing 71 and receives the lower end of the compression coil spring 82. 90a is an O-ring for sealing.

The high-pressure side refrigerant flow path 73 is always in communication with the through hole 77 at the lower end of the valve body 75, and is closed with the flow rate adjustment chamber 74 by a first seal portion 76. Further, the low pressure side refrigerant flow path 72 is arranged so as to open toward the side surface of the valve body 75.
It is communicatively connected to the 2181 adjustment room 74. Therefore, in the state shown in FIG. 7, the first seal portion 76 and the second seal portion 79 create an interlayer between the high pressure side cold tofu flow path 73 and the low pressure side cold tofu flow path 72, and the spring of the compression coil spring 82 is When the valve body 75 moves downward against the force, both the first seal part 76 and the second seal part 79 open, and the refrigerant flows into the high pressure side refrigerant flow path, as shown in FIG. 73 and flows into the low pressure side refrigerant flow path 72.

A diaphragm chamber partitioned by a diaphragm 83 into an upper high pressure chamber 84 and a lower low pressure chamber 85 is formed at the upper end of the casing 71 . The diaphragm 83 is a thin membrane plate that is freely displaceable in its surface direction (that is, in the vertical direction), and its effective diameter is, for example, the same as that of the first or second seal portion 7.
It is about 1.5 to 3 times the diameter of 6.79.

87 is a housing for a temperature sensing part 88 disposed in the refrigerant flow path 91 on the outlet side of the evaporator 1, and is fixed to the upper end of the casing 71, sandwiching it between the high pressure chamber 84 of the Guiaflat chamber and the partition plate 93). ing.

Inside the housing 87, chilled tofu is sealed. 89 is
This is an injection pipe for injecting refrigerant into the housing 87, and its end is sealed. 93a is a communication hole that communicates the high pressure chamber 84 of the diaphragm chamber with the temperature sensing section 88.

On the other hand, the low pressure chamber 85 communicates with an outlet side refrigerant flow path 91 of the evaporator l via a communication path 92. Therefore, the pressure inside the low pressure chamber 85 is always equal to the pressure on the outlet side of the evaporator 1.

As a result, no pressure difference occurs between the high pressure chamber 84 and the low pressure chamber 85 until the refrigerant gas at the outlet of the evaporator 1 reaches saturated vapor, and when the cold gas at the outlet of the evaporator 1 becomes superheated vapor. The pressure in the high pressure chamber 84 becomes higher than the pressure in the low pressure chamber 85, and the diaphragm 83 is pushed down into the low pressure chamber 85 (l!l (i.e., downward).

A plate 94 is in contact with the lower surface of the diaphragm 83 and is sunk in.
An elongated rod 95 is provided so as to be movable forward and backward in the axial direction. The diameter of this rod 95 is smaller than the effective diameter of the diaphragm 83, and the diameter of the rod 95 is smaller than the effective diameter of the diaphragm 83.
In this embodiment, the diameter of the rod 95 is one-third or less of the diameter of the valve body 75, and the cross-sectional area of the rod 95 is smaller than the diameter of the first or second valve body 75. 10 compared to the inner surface a (i.e., pressure receiving area) of the seal portion 76.79.
It is about 1/10th of that.

The lower end of the rod 95 is in contact with a stay 80 formed on the E section inner cutter of the inner cylinder 75a of the valve body 75. The rod 95 passes through a hole formed in the stopper body 78 with its axis aligned with that of the valve body 75, and the upper end of the mouth and door 95 abuts against the plate 94. 96 is an O-ring for sealing. 9
7 is a donut-shaped holding plate for preventing the O-ring 96 from being pulled out.

Therefore, when the diaphragm 83 is pushed down due to the pressure difference between the high pressure chamber 84 and the low pressure chamber 85, the valve body 75 is pushed down via the rod 95, as shown in FIG. The two seals 79 open together, and the refrigerant flows from the high-pressure side refrigerant flow path 73 to the low-pressure side refrigerant flow path 7.
Sent to 2. Then, the valve body 75 comes to rest at a position where the coil spring 82 is compressed and the pressure difference between the high pressure chamber 84 and the low pressure chamber 85 balances the repulsive force of the coil spring 82.

In the embodiment configured in this way, the influence of the pressure of the refrigerant in the high-pressure side refrigerant flow path 73 and the low-pressure side refrigerant flow path 72 on the diaphragm 83 is greatly reduced, just like in each of the previously described embodiments. Moreover, since there is no need to provide a sealing material such as an O-ring or a gasket on the first seal portion 76, there is no resistance to the movement of the valve body 75, and the valve body 75 operates smoothly and accurately. be able to.

[Effects of the Invention j] According to the temperature-operated expansion valve of the present invention, the opening/closing operation of the valve is not affected by the pressure of the refrigerant in the expansion valve, but is affected only by the pressure of the refrigerant gas exiting the evaporator and the temperature of the refrigerant gas. Basically, since the driving means controls the opening and closing operations of the valve, 1. For example, the diaphragm used as the driving means is made smaller to make the device more compact.
In addition, even if the diameter of the valve is increased to increase the refrigerating capacity, complete external pressure equalization type flow control is performed, making it possible to maintain cold tofu! ft)
It has an excellent effect that can be precisely controlled.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a first embodiment of the invention. FIG. 2 is a perspective view of the vicinity of the lower portion of the rod of this embodiment. FIG. 3 is a longitudinal sectional view of the first embodiment with the valve in an open state. ff Figure 14 is a vertical cross-sectional view of the second embodiment of the present invention, and Figure 5 is a vertical cross-sectional view of the third embodiment of the present invention. FIG. 6 is a longitudinal sectional view of a fourth embodiment of the present invention. FIG. 7 is a longitudinal sectional view of a fifth embodiment of the present invention, FIG. 8 is a perspective view with a part of the valve body of the embodiment cut away, and FIG. 9 is a view of the valve of the fifth embodiment. FIG. 1O is a vertical cross-sectional view of the conventional example. DESCRIPTION OF SYMBOLS 1... Evaporator, 1O... Expansion valve, 11... Casing, 12... First refrigerant flow path, 13... Second refrigerant flow path, 14... Ruken gR arrangement Chamber, 5th... Valve body, 1
6... First seal portion, 17... Through hole, 19...
Second seal portion, 22... Coil spring, 23.
...diaplum? 4... High pressure chamber, 25... Low pressure chamber, 27... Housing, 28... Sensitive chamber, 32...
...Communication path, 35...Port, 55...Rod, 6
2... first refrigerant flow path, 63... second cold tofu flow path,
66... First seal part, 69... Second seal part, 72... First refrigerant channel, 73... Second chilled tofu channel, 74... Flow rate adjustment chamber, 75...valve body, 76...
・First seal portion, 79...Second seal portion, 82・
...Coil spring, 83...Diaphragm, 88
...Temperature sensing part, 95...rod. Agent Patent Attorney Kazuhiko Mitsui Figure 2 Figure j Figure 8 Figure 9

Claims (2)

[Claims] (1) A flow rate adjustment chamber formed in the casing to adjust the flow rate of the refrigerant, and a through hole for passing the refrigerant formed in the axial direction, and arranged within the flow rate adjustment chamber so as to be movable forward and backward in the axial direction. a first refrigerant flow path connected to the flow rate adjustment chamber so as to open toward a side surface of the valve body at one end side of the valve body; a second refrigerant flow path that communicates with the through hole; a first seal portion for sealing between the first refrigerant flow path and the second refrigerant flow path along the outer periphery of the valve body; , a second seal formed to have approximately the same diameter as the first seal portion in order to seal between the through hole and the first refrigerant flow path at the edge on the one end side of the valve body; a slender rod that is thinner than the valve body and is provided so as to be movable along the axial direction of the valve body in order to drive the valve body in the axial direction; and a pressure of refrigerant gas exiting the evaporator. and a driving means that operates based on the temperature of the refrigerant gas to drive the rod in the axial direction. (2) A flow rate adjustment chamber formed in the casing to adjust the flow rate of the refrigerant, and a through hole for passing the refrigerant formed in the axial direction, and arranged in the flow rate adjustment chamber so as to be movable forward and backward in the axial direction. a first refrigerant flow path connected to the flow rate adjustment chamber so as to open toward a side surface of the valve body at one end side of the valve body; a second refrigerant flow path communicating with the flow rate adjustment chamber and the through hole; and a first refrigerant flow path for sealing between the flow rate adjustment chamber and the second refrigerant flow path on the other end side of the valve body. a seal portion, and a first seal portion formed to have approximately the same diameter as the first seal portion in order to seal between the through hole and the first refrigerant flow path at the edge of the one end side of the valve body. 2, a long and thin rod that is thinner than the valve body and is movable along the axial direction of the valve body in order to drive the valve body in the axial direction; and a refrigerant exiting the evaporator. a driving means that operates based on the pressure of the gas and the temperature of the refrigerant gas to drive the rod in the axial direction, and the driving means drives the valve body in the axial direction via the rod. A temperature-operated expansion valve characterized in that the first and second seal portions are opened and closed by being driven forward and backward.